Merge remote-tracking branch 'nixpkgs/master' into master

83 files changed, 2262 insertions, 802 deletions

diff --git a/nixos/modules/services/computing/foldingathome/client.nix b/nixos/modules/services/computing/foldingathome/client.nix
new file mode 100644
index 00000000000..9f99af48c48
--- /dev/null
+++ b/nixos/modules/services/computing/foldingathome/client.nix
@@ -0,0 +1,81 @@
+{ config, lib, pkgs, ... }:
+with lib;
+let
+  cfg = config.services.foldingathome;
+
+  args =
+    ["--team" "${toString cfg.team}"]
+    ++ lib.optionals (cfg.user != null) ["--user" cfg.user]
+    ++ cfg.extraArgs
+    ;
+in
+{
+  imports = [
+    (mkRenamedOptionModule [ "services" "foldingAtHome" ] [ "services" "foldingathome" ])
+    (mkRenamedOptionModule [ "services" "foldingathome" "nickname" ] [ "services" "foldingathome" "user" ])
+    (mkRemovedOptionModule [ "services" "foldingathome" "config" ] ''
+      Use <literal>services.foldingathome.extraArgs instead<literal>
+    '')
+  ];
+  options.services.foldingathome = {
+    enable = mkEnableOption "Enable the Folding@home client";
+
+    package = mkOption {
+      type = types.package;
+      default = pkgs.fahclient;
+      defaultText = "pkgs.fahclient";
+      description = ''
+        Which Folding@home client to use.
+      '';
+    };
+
+    user = mkOption {
+      type = types.nullOr types.str;
+      default = null;
+      description = ''
+        The user associated with the reported computation results. This will
+        be used in the ranking statistics.
+      '';
+    };
+
+    team = mkOption {
+      type = types.int;
+      default = 236565;
+      description = ''
+        The team ID associated with the reported computation results. This
+        will be used in the ranking statistics.
+
+        By default, use the NixOS folding@home team ID is being used.
+      '';
+    };
+
+    extraArgs = mkOption {
+      type = types.listOf types.str;
+      default = [];
+      description = ''
+        Extra startup options for the FAHClient. Run
+        <literal>FAHClient --help</literal> to find all the available options.
+      '';
+    };
+  };
+
+  config = mkIf cfg.enable {
+    systemd.services.foldingathome = {
+      description = "Folding@home client";
+      after = [ "network.target" ];
+      wantedBy = [ "multi-user.target" ];
+      script = ''
+        exec ${cfg.package}/bin/FAHClient ${lib.escapeShellArgs args}
+      '';
+      serviceConfig = {
+        DynamicUser = true;
+        StateDirectory = "foldingathome";
+        WorkingDirectory = "%S/foldingathome";
+      };
+    };
+  };
+
+  meta = {
+    maintainers = with lib.maintainers; [ zimbatm ];
+  };
+}
diff --git a/nixos/modules/services/computing/slurm/slurm.nix b/nixos/modules/services/computing/slurm/slurm.nix
index c70d999ca96..050872e933f 100644
--- a/nixos/modules/services/computing/slurm/slurm.nix
+++ b/nixos/modules/services/computing/slurm/slurm.nix
@@ -355,6 +355,7 @@ in
         ExecStart = "${wrappedSlurm}/bin/slurmd";
         PIDFile = "/run/slurmd.pid";
         ExecReload = "${pkgs.coreutils}/bin/kill -HUP $MAINPID";
+        LimitMEMLOCK = "infinity";
       };
 
       preStart = ''
diff --git a/nixos/modules/services/continuous-integration/buildkite-agents.nix b/nixos/modules/services/continuous-integration/buildkite-agents.nix
index fbda2731bbf..c17d89c387a 100644
--- a/nixos/modules/services/continuous-integration/buildkite-agents.nix
+++ b/nixos/modules/services/continuous-integration/buildkite-agents.nix
@@ -258,7 +258,7 @@ in
   });
 
   config.assertions = mapAgents (name: cfg: [
-      { assertion = cfg.hooksPath == hooksDir || all (v: v == null) (attrValues cfg.hooks);
+      { assertion = cfg.hooksPath == (hooksDir cfg) || all (v: v == null) (attrValues cfg.hooks);
         message = ''
           Options `services.buildkite-agents.${name}.hooksPath' and
           `services.buildkite-agents.${name}.hooks.<name>' are mutually exclusive.
diff --git a/nixos/modules/services/databases/mysql.nix b/nixos/modules/services/databases/mysql.nix
index 8d520b82fb5..f9e657f5774 100644
--- a/nixos/modules/services/databases/mysql.nix
+++ b/nixos/modules/services/databases/mysql.nix
@@ -10,16 +10,13 @@ let
 
   isMariaDB = lib.getName mysql == lib.getName pkgs.mariadb;
 
-  isMysqlAtLeast57 =
-    (lib.getName mysql == lib.getName pkgs.mysql57)
-     && (builtins.compareVersions mysql.version "5.7" >= 0);
-
   mysqldOptions =
     "--user=${cfg.user} --datadir=${cfg.dataDir} --basedir=${mysql}";
-  # For MySQL 5.7+, --insecure creates the root user without password
-  # (earlier versions and MariaDB do this by default).
-  installOptions =
-    "${mysqldOptions} ${lib.optionalString isMysqlAtLeast57 "--insecure"}";
+
+  settingsFile = pkgs.writeText "my.cnf" (
+    generators.toINI { listsAsDuplicateKeys = true; } cfg.settings +
+    optionalString (cfg.extraOptions != null) "[mysqld]\n${cfg.extraOptions}"
+  );
 
 in
 
@@ -76,9 +73,64 @@ in
         description = "Location where MySQL stores its table files";
       };
 
+      configFile = mkOption {
+        type = types.path;
+        default = settingsFile;
+        defaultText = "settingsFile";
+        description = ''
+          Override the configuration file used by MySQL. By default,
+          NixOS generates one automatically from <option>services.mysql.settings</option>.
+        '';
+        example = literalExample ''
+          pkgs.writeText "my.cnf" '''
+            [mysqld]
+            datadir = /var/lib/mysql
+            bind-address = 127.0.0.1
+            port = 3336
+            plugin-load-add = auth_socket.so
+
+            !includedir /etc/mysql/conf.d/
+          ''';
+        '';
+      };
+
+      settings = mkOption {
+        type = with types; attrsOf (attrsOf (oneOf [ bool int str (listOf str) ]));
+        default = {};
+        description = ''
+          MySQL configuration. Refer to
+          <link xlink:href="https://dev.mysql.com/doc/refman/5.7/en/server-system-variables.html"/>,
+          <link xlink:href="https://dev.mysql.com/doc/refman/8.0/en/server-system-variables.html"/>,
+          and <link xlink:href="https://mariadb.com/kb/en/server-system-variables/"/>
+          for details on supported values.
+
+          <note>
+            <para>
+              MySQL configuration options such as <literal>--quick</literal> should be treated as
+              boolean options and provided values such as <literal>true</literal>, <literal>false</literal>,
+              <literal>1</literal>, or <literal>0</literal>. See the provided example below.
+            </para>
+          </note>
+        '';
+        example = literalExample ''
+          {
+            mysqld = {
+              key_buffer_size = "6G";
+              table_cache = 1600;
+              log-error = "/var/log/mysql_err.log";
+              plugin-load-add = [ "server_audit" "ed25519=auth_ed25519" ];
+            };
+            mysqldump = {
+              quick = true;
+              max_allowed_packet = "16M";
+            };
+          }
+        '';
+      };
+
       extraOptions = mkOption {
-        type = types.lines;
-        default = "";
+        type = with types; nullOr lines;
+        default = null;
         example = ''
           key_buffer_size = 6G
           table_cache = 1600
@@ -252,10 +304,27 @@ in
 
   config = mkIf config.services.mysql.enable {
 
+    warnings = optional (cfg.extraOptions != null) "services.mysql.`extraOptions` is deprecated, please use services.mysql.`settings`.";
+
     services.mysql.dataDir =
       mkDefault (if versionAtLeast config.system.stateVersion "17.09" then "/var/lib/mysql"
                  else "/var/mysql");
 
+    services.mysql.settings.mysqld = mkMerge [
+      {
+        datadir = cfg.dataDir;
+        bind-address = mkIf (cfg.bind != null) cfg.bind;
+        port = cfg.port;
+        plugin-load-add = optional (cfg.ensureUsers != []) "auth_socket.so";
+      }
+      (mkIf (cfg.replication.role == "master" || cfg.replication.role == "slave") {
+        log-bin = "mysql-bin-${toString cfg.replication.serverId}";
+        log-bin-index = "mysql-bin-${toString cfg.replication.serverId}.index";
+        relay-log = "mysql-relay-bin";
+        server-id = cfg.replication.serverId;
+      })
+    ];
+
     users.users.mysql = {
       description = "MySQL server user";
       group = "mysql";
@@ -266,25 +335,7 @@ in
 
     environment.systemPackages = [mysql];
 
-    environment.etc."my.cnf".text =
-    ''
-      [mysqld]
-      port = ${toString cfg.port}
-      datadir = ${cfg.dataDir}
-      ${optionalString (cfg.bind != null) "bind-address = ${cfg.bind}" }
-      ${optionalString (cfg.replication.role == "master" || cfg.replication.role == "slave")
-      ''
-        log-bin=mysql-bin-${toString cfg.replication.serverId}
-        log-bin-index=mysql-bin-${toString cfg.replication.serverId}.index
-        relay-log=mysql-relay-bin
-        server-id = ${toString cfg.replication.serverId}
-      ''}
-      ${optionalString (cfg.ensureUsers != [])
-      ''
-        plugin-load-add = auth_socket.so
-      ''}
-      ${cfg.extraOptions}
-    '';
+    environment.etc."my.cnf".source = cfg.configFile;
 
     systemd.tmpfiles.rules = [
       "d '${cfg.dataDir}' 0700 ${cfg.user} mysql -"
@@ -297,7 +348,7 @@ in
 
         after = [ "network.target" ];
         wantedBy = [ "multi-user.target" ];
-        restartTriggers = [ config.environment.etc."my.cnf".source ];
+        restartTriggers = [ cfg.configFile ];
 
         unitConfig.RequiresMountsFor = "${cfg.dataDir}";
 
@@ -307,9 +358,14 @@ in
           pkgs.nettools
         ];
 
-        preStart = ''
+        preStart = if isMariaDB then ''
+          if ! test -e ${cfg.dataDir}/mysql; then
+            ${mysql}/bin/mysql_install_db --defaults-file=/etc/my.cnf ${mysqldOptions}
+            touch /tmp/mysql_init
+          fi
+        '' else ''
           if ! test -e ${cfg.dataDir}/mysql; then
-            ${mysql}/bin/mysql_install_db --defaults-file=/etc/my.cnf ${installOptions}
+            ${mysql}/bin/mysqld --defaults-file=/etc/my.cnf ${mysqldOptions} --initialize-insecure
             touch /tmp/mysql_init
           fi
         '';
diff --git a/nixos/modules/services/desktops/gnome3/rygel.nix b/nixos/modules/services/desktops/gnome3/rygel.nix
index 55d5e703aa1..b6c44590a2e 100644
--- a/nixos/modules/services/desktops/gnome3/rygel.nix
+++ b/nixos/modules/services/desktops/gnome3/rygel.nix
@@ -26,5 +26,7 @@ with lib;
     services.dbus.packages = [ pkgs.gnome3.rygel ];
 
     systemd.packages = [ pkgs.gnome3.rygel ];
+
+    environment.etc."rygel.conf" = "${pkgs.gnome3.rygel}/etc/rygel.conf";
   };
 }
diff --git a/nixos/modules/services/desktops/malcontent.nix b/nixos/modules/services/desktops/malcontent.nix
new file mode 100644
index 00000000000..416464cbe08
--- /dev/null
+++ b/nixos/modules/services/desktops/malcontent.nix
@@ -0,0 +1,32 @@
+# Malcontent daemon.
+
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+{
+
+  ###### interface
+
+  options = {
+
+    services.malcontent = {
+
+      enable = mkEnableOption "Malcontent";
+
+    };
+
+  };
+
+
+  ###### implementation
+
+  config = mkIf config.services.malcontent.enable {
+
+    environment.systemPackages = [ pkgs.malcontent ];
+
+    services.dbus.packages = [ pkgs.malcontent ];
+
+  };
+
+}
diff --git a/nixos/modules/services/hardware/tlp.nix b/nixos/modules/services/hardware/tlp.nix
index 955a6067799..3962d7b1598 100644
--- a/nixos/modules/services/hardware/tlp.nix
+++ b/nixos/modules/services/hardware/tlp.nix
@@ -1,39 +1,26 @@
 { config, lib, pkgs, ... }:
-
 with lib;
-
 let
-
-cfg = config.services.tlp;
-
-enableRDW = config.networking.networkmanager.enable;
-
-tlp = pkgs.tlp.override {
-  inherit enableRDW;
-};
-
-# XXX: We can't use writeTextFile + readFile here because it triggers
-# TLP build to get the .drv (even on --dry-run).
-confFile = pkgs.runCommand "tlp"
-  { config = cfg.extraConfig;
-    passAsFile = [ "config" ];
-    preferLocalBuild = true;
-  }
-  ''
-    cat ${tlp}/etc/default/tlp > $out
-    cat $configPath >> $out
-  '';
-
+  cfg = config.services.tlp;
+  enableRDW = config.networking.networkmanager.enable;
+  tlp = pkgs.tlp.override { inherit enableRDW; };
+  # TODO: Use this for having proper parameters in the future
+  mkTlpConfig = tlpConfig: generators.toKeyValue {
+    mkKeyValue = generators.mkKeyValueDefault {
+      mkValueString = val:
+        if isInt val then toString val
+        else if isString val then val
+        else if true == val then "1"
+        else if false == val then "0"
+        else if isList val then "\"" + (concatStringsSep " " val) + "\""
+        else err "invalid value provided to mkTlpConfig:" (toString val);
+    } "=";
+  } tlpConfig;
 in
-
 {
-
   ###### interface
-
   options = {
-
     services.tlp = {
-
       enable = mkOption {
         type = types.bool;
         default = false;
@@ -45,77 +32,64 @@ in
         default = "";
         description = "Additional configuration variables for TLP";
       };
-
     };
-
   };
 
-
   ###### implementation
-
   config = mkIf cfg.enable {
+    boot.kernelModules = [ "msr" ];
 
-    powerManagement.scsiLinkPolicy = null;
-    powerManagement.cpuFreqGovernor = null;
-    powerManagement.cpufreq.max = null;
-    powerManagement.cpufreq.min = null;
+    environment.etc = {
+      "tlp.conf".text = cfg.extraConfig;
+    } // optionalAttrs enableRDW {
+      "NetworkManager/dispatcher.d/99tlp-rdw-nm".source =
+        "${tlp}/etc/NetworkManager/dispatcher.d/99tlp-rdw-nm";
+    };
 
-    systemd.sockets.systemd-rfkill.enable = false;
+    environment.systemPackages = [ tlp ];
 
-    systemd.services = {
-      "systemd-rfkill@".enable = false;
-      systemd-rfkill.enable = false;
+    # FIXME: When the config is parametrized we need to move these into a
+    # conditional on the relevant options being enabled.
+    powerManagement = {
+      scsiLinkPolicy = null;
+      cpuFreqGovernor = null;
+      cpufreq.max = null;
+      cpufreq.min = null;
+    };
 
-      tlp = {
-        description = "TLP system startup/shutdown";
+    services.udev.packages = [ tlp ];
 
-        after = [ "multi-user.target" ];
+    systemd = {
+      packages = [ tlp ];
+      # XXX: These must always be disabled/masked according to [1].
+      #
+      # [1]: https://github.com/linrunner/TLP/blob/a9ada09e0821f275ce5f93dc80a4d81a7ff62ae4/tlp-stat.in#L319
+      sockets.systemd-rfkill.enable = false;
+      services.systemd-rfkill.enable = false;
+
+      services.tlp = {
+        # XXX: The service should reload whenever the configuration changes,
+        # otherwise newly set power options remain inactive until reboot (or
+        # manual unit restart.)
+        restartTriggers = [ config.environment.etc."tlp.conf".source ];
+        # XXX: When using systemd.packages (which we do above) the [Install]
+        # section of systemd units does not work (citation needed) so we manually
+        # enforce it here.
         wantedBy = [ "multi-user.target" ];
-        before = [ "shutdown.target" ];
-        restartTriggers = [ confFile ];
-
-        serviceConfig = {
-          Type = "oneshot";
-          RemainAfterExit = true;
-          ExecStart = "${tlp}/bin/tlp init start";
-          ExecStop = "${tlp}/bin/tlp init stop";
-        };
       };
 
-      tlp-sleep = {
-        description = "TLP suspend/resume";
-
-        wantedBy = [ "sleep.target" ];
+      services.tlp-sleep = {
+        # XXX: When using systemd.packages (which we do above) the [Install]
+        # section of systemd units does not work (citation needed) so we manually
+        # enforce it here.
         before = [ "sleep.target" ];
-
-        unitConfig = {
-          StopWhenUnneeded = true;
-        };
-
-        serviceConfig = {
-          Type = "oneshot";
-          RemainAfterExit = true;
-          ExecStart = "${tlp}/bin/tlp suspend";
-          ExecStop = "${tlp}/bin/tlp resume";
-        };
+        wantedBy = [ "sleep.target" ];
+        # XXX: `tlp suspend` requires /var/lib/tlp to exist in order to save
+        # some stuff in there. There is no way, that I know of, to do this in
+        # the package itself, so we do it here instead making sure the unit
+        # won't fail due to the save dir not existing.
+        serviceConfig.StateDirectory = "tlp";
       };
     };
-
-    services.udev.packages = [ tlp ];
-
-    environment.etc =
-      {
-        "default/tlp".source = confFile;
-      } // optionalAttrs enableRDW {
-        "NetworkManager/dispatcher.d/99tlp-rdw-nm" = {
-          source = "${tlp}/etc/NetworkManager/dispatcher.d/99tlp-rdw-nm";
-        };
-      };
-
-    environment.systemPackages = [ tlp ];
-
-    boot.kernelModules = [ "msr" ];
-
   };
-
 }
diff --git a/nixos/modules/services/mail/dovecot.nix b/nixos/modules/services/mail/dovecot.nix
index b5ed2c594f7..230a2ae3f82 100644
--- a/nixos/modules/services/mail/dovecot.nix
+++ b/nixos/modules/services/mail/dovecot.nix
@@ -14,18 +14,34 @@ let
       base_dir = ${baseDir}
       protocols = ${concatStringsSep " " cfg.protocols}
       sendmail_path = /run/wrappers/bin/sendmail
+      # defining mail_plugins must be done before the first protocol {} filter because of https://doc.dovecot.org/configuration_manual/config_file/config_file_syntax/#variable-expansion
+      mail_plugins = $mail_plugins ${concatStringsSep " " cfg.mailPlugins.globally.enable}
     ''
 
-    (if cfg.sslServerCert == null then ''
-      ssl = no
-      disable_plaintext_auth = no
-    '' else ''
-      ssl_cert = <${cfg.sslServerCert}
-      ssl_key = <${cfg.sslServerKey}
-      ${optionalString (cfg.sslCACert != null) ("ssl_ca = <" + cfg.sslCACert)}
-      ssl_dh = <${config.security.dhparams.params.dovecot2.path}
-      disable_plaintext_auth = yes
-    '')
+    (
+      concatStringsSep "\n" (
+        mapAttrsToList (
+          protocol: plugins: ''
+            protocol ${protocol} {
+              mail_plugins = $mail_plugins ${concatStringsSep " " plugins.enable}
+            }
+          ''
+        ) cfg.mailPlugins.perProtocol
+      )
+    )
+
+    (
+      if cfg.sslServerCert == null then ''
+        ssl = no
+        disable_plaintext_auth = no
+      '' else ''
+        ssl_cert = <${cfg.sslServerCert}
+        ssl_key = <${cfg.sslServerKey}
+        ${optionalString (cfg.sslCACert != null) ("ssl_ca = <" + cfg.sslCACert)}
+        ssl_dh = <${config.security.dhparams.params.dovecot2.path}
+        disable_plaintext_auth = yes
+      ''
+    )
 
     ''
       default_internal_user = ${cfg.user}
@@ -45,55 +61,58 @@ let
       }
     ''
 
-    (optionalString cfg.enablePAM ''
-      userdb {
-        driver = passwd
-      }
-
-      passdb {
-        driver = pam
-        args = ${optionalString cfg.showPAMFailure "failure_show_msg=yes"} dovecot2
-      }
-    '')
+    (
+      optionalString cfg.enablePAM ''
+        userdb {
+          driver = passwd
+        }
 
-    (optionalString (cfg.sieveScripts != {}) ''
-      plugin {
-        ${concatStringsSep "\n" (mapAttrsToList (to: from: "sieve_${to} = ${stateDir}/sieve/${to}") cfg.sieveScripts)}
-      }
-    '')
+        passdb {
+          driver = pam
+          args = ${optionalString cfg.showPAMFailure "failure_show_msg=yes"} dovecot2
+        }
+      ''
+    )
 
-    (optionalString (cfg.mailboxes != []) ''
-      protocol imap {
-        namespace inbox {
-          inbox=yes
-          ${concatStringsSep "\n" (map mailboxConfig cfg.mailboxes)}
+    (
+      optionalString (cfg.sieveScripts != {}) ''
+        plugin {
+          ${concatStringsSep "\n" (mapAttrsToList (to: from: "sieve_${to} = ${stateDir}/sieve/${to}") cfg.sieveScripts)}
         }
-      }
-    '')
-
-    (optionalString cfg.enableQuota ''
-      mail_plugins = $mail_plugins quota
-      service quota-status {
-        executable = ${dovecotPkg}/libexec/dovecot/quota-status -p postfix
-        inet_listener {
-          port = ${cfg.quotaPort}
+      ''
+    )
+
+    (
+      optionalString (cfg.mailboxes != []) ''
+        protocol imap {
+          namespace inbox {
+            inbox=yes
+            ${concatStringsSep "\n" (map mailboxConfig cfg.mailboxes)}
+          }
+        }
+      ''
+    )
+
+    (
+      optionalString cfg.enableQuota ''
+        service quota-status {
+          executable = ${dovecotPkg}/libexec/dovecot/quota-status -p postfix
+          inet_listener {
+            port = ${cfg.quotaPort}
+          }
+          client_limit = 1
         }
-        client_limit = 1
-      }
-
-      protocol imap {
-        mail_plugins = $mail_plugins imap_quota
-      }
 
-      plugin {
-        quota_rule = *:storage=${cfg.quotaGlobalPerUser}
-        quota = maildir:User quota # per virtual mail user quota # BUG/FIXME broken, we couldn't get this working
-        quota_status_success = DUNNO
-        quota_status_nouser = DUNNO
-        quota_status_overquota = "552 5.2.2 Mailbox is full"
-        quota_grace = 10%%
-      }
-    '')
+        plugin {
+          quota_rule = *:storage=${cfg.quotaGlobalPerUser}
+          quota = maildir:User quota # per virtual mail user quota # BUG/FIXME broken, we couldn't get this working
+          quota_status_success = DUNNO
+          quota_status_nouser = DUNNO
+          quota_status_overquota = "552 5.2.2 Mailbox is full"
+          quota_grace = 10%%
+        }
+      ''
+    )
 
     cfg.extraConfig
   ];
@@ -107,7 +126,7 @@ let
     mailbox "${mailbox.name}" {
       auto = ${toString mailbox.auto}
   '' + optionalString (mailbox.specialUse != null) ''
-      special_use = \${toString mailbox.specialUse}
+    special_use = \${toString mailbox.specialUse}
   '' + "}";
 
   mailboxes = { ... }: {
@@ -160,7 +179,7 @@ in
 
     protocols = mkOption {
       type = types.listOf types.str;
-      default = [ ];
+      default = [];
       description = "Additional listeners to start when Dovecot is enabled.";
     };
 
@@ -183,6 +202,43 @@ in
       description = "Additional entries to put verbatim into Dovecot's config file.";
     };
 
+    mailPlugins =
+      let
+        plugins = hint: types.submodule {
+          options = {
+            enable = mkOption {
+              type = types.listOf types.str;
+              default = [];
+              description = "mail plugins to enable as a list of strings to append to the ${hint} <literal>$mail_plugins</literal> configuration variable";
+            };
+          };
+        };
+      in
+        mkOption {
+          type = with types; submodule {
+            options = {
+              globally = mkOption {
+                description = "Additional entries to add to the mail_plugins variable for all protocols";
+                type = plugins "top-level";
+                example = { enable = [ "virtual" ]; };
+                default = { enable = []; };
+              };
+              perProtocol = mkOption {
+                description = "Additional entries to add to the mail_plugins variable, per protocol";
+                type = attrsOf (plugins "corresponding per-protocol");
+                default = {};
+                example = { imap = [ "imap_acl" ]; };
+              };
+            };
+          };
+          description = "Additional entries to add to the mail_plugins variable, globally and per protocol";
+          example = {
+            globally.enable = [ "acl" ];
+            perProtocol.imap.enable = [ "imap_acl" ];
+          };
+          default = { globally.enable = []; perProtocol = {}; };
+        };
+
     configFile = mkOption {
       type = types.nullOr types.path;
       default = null;
@@ -305,27 +361,33 @@ in
       enable = true;
       params.dovecot2 = {};
     };
-   services.dovecot2.protocols =
-     optional cfg.enableImap "imap"
-     ++ optional cfg.enablePop3 "pop3"
-     ++ optional cfg.enableLmtp "lmtp";
+    services.dovecot2.protocols =
+      optional cfg.enableImap "imap"
+      ++ optional cfg.enablePop3 "pop3"
+      ++ optional cfg.enableLmtp "lmtp";
+
+    services.dovecot2.mailPlugins = mkIf cfg.enableQuota {
+      globally.enable = [ "quota" ];
+      perProtocol.imap.enable = [ "imap_quota" ];
+    };
 
     users.users = {
       dovenull =
-        { uid = config.ids.uids.dovenull2;
+        {
+          uid = config.ids.uids.dovenull2;
           description = "Dovecot user for untrusted logins";
           group = "dovenull";
         };
     } // optionalAttrs (cfg.user == "dovecot2") {
       dovecot2 =
-         { uid = config.ids.uids.dovecot2;
-           description = "Dovecot user";
-           group = cfg.group;
-         };
+        {
+          uid = config.ids.uids.dovecot2;
+          description = "Dovecot user";
+          group = cfg.group;
+        };
     } // optionalAttrs (cfg.createMailUser && cfg.mailUser != null) {
       ${cfg.mailUser} =
-        { description = "Virtual Mail User"; } //
-        optionalAttrs (cfg.mailGroup != null)
+        { description = "Virtual Mail User"; } // optionalAttrs (cfg.mailGroup != null)
           { group = cfg.mailGroup; };
     };
 
@@ -334,7 +396,7 @@ in
     } // optionalAttrs (cfg.group == "dovecot2") {
       dovecot2.gid = config.ids.gids.dovecot2;
     } // optionalAttrs (cfg.createMailUser && cfg.mailGroup != null) {
-      ${cfg.mailGroup} = { };
+      ${cfg.mailGroup} = {};
     };
 
     environment.etc."dovecot/modules".source = modulesDir;
@@ -363,15 +425,19 @@ in
         rm -rf ${stateDir}/sieve
       '' + optionalString (cfg.sieveScripts != {}) ''
         mkdir -p ${stateDir}/sieve
-        ${concatStringsSep "\n" (mapAttrsToList (to: from: ''
-          if [ -d '${from}' ]; then
-            mkdir '${stateDir}/sieve/${to}'
-            cp -p "${from}/"*.sieve '${stateDir}/sieve/${to}'
-          else
-            cp -p '${from}' '${stateDir}/sieve/${to}'
-          fi
-          ${pkgs.dovecot_pigeonhole}/bin/sievec '${stateDir}/sieve/${to}'
-        '') cfg.sieveScripts)}
+        ${concatStringsSep "\n" (
+        mapAttrsToList (
+          to: from: ''
+            if [ -d '${from}' ]; then
+              mkdir '${stateDir}/sieve/${to}'
+              cp -p "${from}/"*.sieve '${stateDir}/sieve/${to}'
+            else
+              cp -p '${from}' '${stateDir}/sieve/${to}'
+            fi
+            ${pkgs.dovecot_pigeonhole}/bin/sievec '${stateDir}/sieve/${to}'
+          ''
+        ) cfg.sieveScripts
+      )}
         chown -R '${cfg.mailUser}:${cfg.mailGroup}' '${stateDir}/sieve'
       '';
     };
@@ -379,17 +445,21 @@ in
     environment.systemPackages = [ dovecotPkg ];
 
     assertions = [
-      { assertion = intersectLists cfg.protocols [ "pop3" "imap" ] != [];
+      {
+        assertion = intersectLists cfg.protocols [ "pop3" "imap" ] != [];
         message = "dovecot needs at least one of the IMAP or POP3 listeners enabled";
       }
-      { assertion = (cfg.sslServerCert == null) == (cfg.sslServerKey == null)
-          && (cfg.sslCACert != null -> !(cfg.sslServerCert == null || cfg.sslServerKey == null));
+      {
+        assertion = (cfg.sslServerCert == null) == (cfg.sslServerKey == null)
+        && (cfg.sslCACert != null -> !(cfg.sslServerCert == null || cfg.sslServerKey == null));
         message = "dovecot needs both sslServerCert and sslServerKey defined for working crypto";
       }
-      { assertion = cfg.showPAMFailure -> cfg.enablePAM;
+      {
+        assertion = cfg.showPAMFailure -> cfg.enablePAM;
         message = "dovecot is configured with showPAMFailure while enablePAM is disabled";
       }
-      { assertion = cfg.sieveScripts != {} -> (cfg.mailUser != null && cfg.mailGroup != null);
+      {
+        assertion = cfg.sieveScripts != {} -> (cfg.mailUser != null && cfg.mailGroup != null);
         message = "dovecot requires mailUser and mailGroup to be set when sieveScripts is set";
       }
     ];
diff --git a/nixos/modules/services/mail/mailman.nix b/nixos/modules/services/mail/mailman.nix
index 43dc185cdd7..f5e78b18293 100644
--- a/nixos/modules/services/mail/mailman.nix
+++ b/nixos/modules/services/mail/mailman.nix
@@ -265,6 +265,11 @@ in {
       '';
       serviceConfig = {
         Type = "oneshot";
+        # RemainAfterExit makes restartIfChanged work for this service, so
+        # downstream services will get updated automatically when things like
+        # services.mailman.hyperkitty.baseUrl change.  Otherwise users have to
+        # restart things manually, which is confusing.
+        RemainAfterExit = "yes";
       };
     };
 
@@ -282,6 +287,9 @@ in {
       serviceConfig = {
         User = cfg.webUser;
         Type = "oneshot";
+        # Similar to mailman-settings.service, this makes restartTriggers work
+        # properly for this service.
+        RemainAfterExit = "yes";
         WorkingDirectory = "/var/lib/mailman-web";
       };
     };
diff --git a/nixos/modules/services/misc/ankisyncd.nix b/nixos/modules/services/misc/ankisyncd.nix
new file mode 100644
index 00000000000..5fc19649d3d
--- /dev/null
+++ b/nixos/modules/services/misc/ankisyncd.nix
@@ -0,0 +1,79 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.ankisyncd;
+
+  name = "ankisyncd";
+
+  stateDir = "/var/lib/${name}";
+
+  authDbPath = "${stateDir}/auth.db";
+
+  sessionDbPath = "${stateDir}/session.db";
+
+  configFile = pkgs.writeText "ankisyncd.conf" (lib.generators.toINI {} {
+    sync_app = {
+      host = cfg.host;
+      port = cfg.port;
+      data_root = stateDir;
+      auth_db_path = authDbPath;
+      session_db_path = sessionDbPath;
+
+      base_url = "/sync/";
+      base_media_url = "/msync/";
+    };
+  });
+in
+  {
+    options.services.ankisyncd = {
+      enable = mkEnableOption "ankisyncd";
+
+      package = mkOption {
+        type = types.package;
+        default = pkgs.ankisyncd;
+        defaultText = literalExample "pkgs.ankisyncd";
+        description = "The package to use for the ankisyncd command.";
+      };
+
+      host = mkOption {
+        type = types.str;
+        default = "localhost";
+        description = "ankisyncd host";
+      };
+
+      port = mkOption {
+        type = types.int;
+        default = 27701;
+        description = "ankisyncd port";
+      };
+
+      openFirewall = mkOption {
+        default = false;
+        type = types.bool;
+        description = "Whether to open the firewall for the specified port.";
+      };
+    };
+
+    config = mkIf cfg.enable {
+      networking.firewall.allowedTCPPorts = mkIf cfg.openFirewall [ cfg.port ];
+
+      environment.etc."ankisyncd/ankisyncd.conf".source = configFile;
+
+      systemd.services.ankisyncd = {
+        description = "ankisyncd - Anki sync server";
+        after = [ "network.target" ];
+        wantedBy = [ "multi-user.target" ];
+        path = [ cfg.package ];
+
+        serviceConfig = {
+          Type = "simple";
+          DynamicUser = true;
+          StateDirectory = name;
+          ExecStart = "${cfg.package}/bin/ankisyncd";
+          Restart = "always";
+        };
+      };
+    };
+  }
diff --git a/nixos/modules/services/misc/autorandr.nix b/nixos/modules/services/misc/autorandr.nix
index 4708e16e2a6..cf7fb5f78d3 100644
--- a/nixos/modules/services/misc/autorandr.nix
+++ b/nixos/modules/services/misc/autorandr.nix
@@ -48,5 +48,5 @@ in {
 
   };
 
-  meta.maintainers = with maintainers; [ gnidorah ma27 ];
+  meta.maintainers = with maintainers; [ gnidorah ];
 }
diff --git a/nixos/modules/services/misc/disnix.nix b/nixos/modules/services/misc/disnix.nix
index c21cb2afc3c..b7b6eb7cd66 100644
--- a/nixos/modules/services/misc/disnix.nix
+++ b/nixos/modules/services/misc/disnix.nix
@@ -61,10 +61,7 @@ in
       ++ optional cfg.useWebServiceInterface "${pkgs.dbus_java}/share/java/dbus.jar";
     services.tomcat.webapps = optional cfg.useWebServiceInterface pkgs.DisnixWebService;
 
-    users.groups = singleton
-      { name = "disnix";
-        gid = config.ids.gids.disnix;
-      };
+    users.groups.disnix.gid = config.ids.gids.disnix;
 
     systemd.services = {
       disnix = mkIf cfg.enableMultiUser {
diff --git a/nixos/modules/services/misc/folding-at-home.nix b/nixos/modules/services/misc/folding-at-home.nix
deleted file mode 100644
index fd2ea3948f6..00000000000
--- a/nixos/modules/services/misc/folding-at-home.nix
+++ /dev/null
@@ -1,67 +0,0 @@
-{ config, lib, pkgs, ... }:
-with lib;
-let
-  stateDir = "/var/lib/foldingathome";
-  cfg = config.services.foldingAtHome;
-  fahUser = "foldingathome";
-in {
-
-  ###### interface
-
-  options = {
-
-    services.foldingAtHome = {
-
-      enable = mkOption {
-        default = false;
-        description = ''
-          Whether to enable the Folding@Home to use idle CPU time.
-        '';
-      };
-
-      nickname = mkOption {
-        default = "Anonymous";
-        description = ''
-          A unique handle for statistics.
-        '';
-      };
-
-      config = mkOption {
-        default = "";
-        description = ''
-          Extra configuration. Contents will be added verbatim to the
-          configuration file.
-        '';
-      };
-
-    };
-
-  };
-
-  ###### implementation
-
-  config = mkIf cfg.enable {
-
-    users.users.${fahUser} =
-      { uid = config.ids.uids.foldingathome;
-        description = "Folding@Home user";
-        home = stateDir;
-      };
-
-    systemd.services.foldingathome = {
-      after = [ "network.target" ];
-      wantedBy = [ "multi-user.target" ];
-      preStart = ''
-        mkdir -m 0755 -p ${stateDir}
-        chown ${fahUser} ${stateDir}
-        cp -f ${pkgs.writeText "client.cfg" cfg.config} ${stateDir}/client.cfg
-      '';
-      script = "${pkgs.su}/bin/su -s ${pkgs.runtimeShell} ${fahUser} -c 'cd ${stateDir}; ${pkgs.foldingathome}/bin/fah6'";
-    };
-
-    services.foldingAtHome.config = ''
-        [settings]
-        username=${cfg.nickname}
-    '';
-  };
-}
diff --git a/nixos/modules/services/misc/home-assistant.nix b/nixos/modules/services/misc/home-assistant.nix
index d63f38e93b8..86033d02bf3 100644
--- a/nixos/modules/services/misc/home-assistant.nix
+++ b/nixos/modules/services/misc/home-assistant.nix
@@ -96,7 +96,20 @@ in {
 
     config = mkOption {
       default = null;
-      type = with types; nullOr attrs;
+      # Migrate to new option types later: https://github.com/NixOS/nixpkgs/pull/75584
+      type =  with lib.types; let
+          valueType = nullOr (oneOf [
+            bool
+            int
+            float
+            str
+            (lazyAttrsOf valueType)
+            (listOf valueType)
+          ]) // {
+            description = "Yaml value";
+            emptyValue.value = {};
+          };
+        in valueType;
       example = literalExample ''
         {
           homeassistant = {
diff --git a/nixos/modules/services/misc/matrix-synapse.nix b/nixos/modules/services/misc/matrix-synapse.nix
index 750f4a292fb..d02fa13bb99 100644
--- a/nixos/modules/services/misc/matrix-synapse.nix
+++ b/nixos/modules/services/misc/matrix-synapse.nix
@@ -111,6 +111,9 @@ app_service_config_files: ${builtins.toJSON cfg.app_service_config_files}
 
 ${cfg.extraConfig}
 '';
+
+  hasLocalPostgresDB = let args = cfg.database_args; in
+    usePostgresql && (!(args ? host) || (elem args.host [ "localhost" "127.0.0.1" "::1" ]));
 in {
   options = {
     services.matrix-synapse = {
@@ -354,13 +357,6 @@ in {
           The database engine name. Can be sqlite or psycopg2.
         '';
       };
-      create_local_database = mkOption {
-        type = types.bool;
-        default = true;
-        description = ''
-          Whether to create a local database automatically.
-        '';
-      };
       database_name = mkOption {
         type = types.str;
         default = "matrix-synapse";
@@ -657,6 +653,25 @@ in {
   };
 
   config = mkIf cfg.enable {
+    assertions = [
+      { assertion = hasLocalPostgresDB -> config.services.postgresql.enable;
+        message = ''
+          Cannot deploy matrix-synapse with a configuration for a local postgresql database
+            and a missing postgresql service. Since 20.03 it's mandatory to manually configure the
+            database (please read the thread in https://github.com/NixOS/nixpkgs/pull/80447 for
+            further reference).
+
+            If you
+            - try to deploy a fresh synapse, you need to configure the database yourself. An example
+              for this can be found in <nixpkgs/nixos/tests/matrix-synapse.nix>
+            - update your existing matrix-synapse instance, you simply need to add `services.postgresql.enable = true`
+              to your configuration.
+
+          For further information about this update, please read the release-notes of 20.03 carefully.
+        '';
+      }
+    ];
+
     users.users.matrix-synapse = { 
         group = "matrix-synapse";
         home = cfg.dataDir;
@@ -669,18 +684,9 @@ in {
       gid = config.ids.gids.matrix-synapse;
     };
 
-    services.postgresql = mkIf (usePostgresql && cfg.create_local_database) {
-      enable = mkDefault true;
-      ensureDatabases = [ cfg.database_name ];
-      ensureUsers = [{
-        name = cfg.database_user;
-        ensurePermissions = { "DATABASE \"${cfg.database_name}\"" = "ALL PRIVILEGES"; };
-      }];
-    };
-
     systemd.services.matrix-synapse = {
       description = "Synapse Matrix homeserver";
-      after = [ "network.target" ] ++ lib.optional config.services.postgresql.enable "postgresql.service" ;
+      after = [ "network.target" ] ++ optional hasLocalPostgresDB "postgresql.service";
       wantedBy = [ "multi-user.target" ];
       preStart = ''
         ${cfg.package}/bin/homeserver \
@@ -709,6 +715,12 @@ in {
       The `trusted_third_party_id_servers` option as been removed in `matrix-synapse` v1.4.0
       as the behavior is now obsolete.
     '')
+    (mkRemovedOptionModule [ "services" "matrix-synapse" "create_local_database" ] ''
+      Database configuration must be done manually. An exemplary setup is demonstrated in
+      <nixpkgs/nixos/tests/matrix-synapse.nix>
+    '')
   ];
 
+  meta.doc = ./matrix-synapse.xml;
+
 }
diff --git a/nixos/modules/services/misc/matrix-synapse.xml b/nixos/modules/services/misc/matrix-synapse.xml
new file mode 100644
index 00000000000..053a3b2a563
--- /dev/null
+++ b/nixos/modules/services/misc/matrix-synapse.xml
@@ -0,0 +1,224 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         version="5.0"
+         xml:id="module-services-matrix">
+ <title>Matrix</title>
+ <para>
+  <link xlink:href="https://matrix.org/">Matrix</link> is an open standard for
+  interoperable, decentralised, real-time communication over IP. It can be used
+  to power Instant Messaging, VoIP/WebRTC signalling, Internet of Things
+  communication - or anywhere you need a standard HTTP API for publishing and
+  subscribing to data whilst tracking the conversation history.
+ </para>
+ <para>
+  This chapter will show you how to set up your own, self-hosted Matrix
+  homeserver using the Synapse reference homeserver, and how to serve your own
+  copy of the Riot web client. See the
+  <link xlink:href="https://matrix.org/docs/projects/try-matrix-now.html">Try
+  Matrix Now!</link> overview page for links to Riot Apps for Android and iOS,
+  desktop clients, as well as bridges to other networks and other projects
+  around Matrix.
+ </para>
+ <section xml:id="module-services-matrix-synapse">
+  <title>Synapse Homeserver</title>
+
+  <para>
+   <link xlink:href="https://github.com/matrix-org/synapse">Synapse</link> is
+   the reference homeserver implementation of Matrix from the core development
+   team at matrix.org. The following configuration example will set up a
+   synapse server for the <literal>example.org</literal> domain, served from
+   the host <literal>myhostname.example.org</literal>. For more information,
+   please refer to the
+   <link xlink:href="https://github.com/matrix-org/synapse#synapse-installation">
+   installation instructions of Synapse </link>.
+<programlisting>
+let
+  fqdn =
+    let
+      join = hostName: domain: hostName + optionalString (domain != null) ".${domain}";
+    in join config.networking.hostName config.networking.domain;
+in {
+  networking = {
+    <link linkend="opt-networking.hostName">hostName</link> = "myhostname";
+    <link linkend="opt-networking.domain">domain</link> = "example.org";
+  };
+  <link linkend="opt-networking.firewall.allowedTCPPorts">networking.firewall.allowedTCPPorts</link> = [ 80 443 ];
+
+  <link linkend="opt-services.postgresql.enable">services.postgresql.enable</link> = true;
+  <link linkend="opt-services.postgresql.initialScript">services.postgresql.initialScript</link> = ''
+    CREATE ROLE "matrix-synapse" WITH LOGIN PASSWORD 'synapse';
+    CREATE DATABASE "matrix-synapse" WITH OWNER "matrix-synapse"
+      TEMPLATE template0
+      LC_COLLATE = "C"
+      LC_CTYPE = "C";
+  '';
+
+  services.nginx = {
+    <link linkend="opt-services.nginx.enable">enable</link> = true;
+    # only recommendedProxySettings and recommendedGzipSettings are strictly required,
+    # but the rest make sense as well
+    <link linkend="opt-services.nginx.recommendedTlsSettings">recommendedTlsSettings</link> = true;
+    <link linkend="opt-services.nginx.recommendedOptimisation">recommendedOptimisation</link> = true;
+    <link linkend="opt-services.nginx.recommendedGzipSettings">recommendedGzipSettings</link> = true;
+    <link linkend="opt-services.nginx.recommendedProxySettings">recommendedProxySettings</link> = true;
+
+    <link linkend="opt-services.nginx.virtualHosts">virtualHosts</link> = {
+      # This host section can be placed on a different host than the rest,
+      # i.e. to delegate from the host being accessible as ${config.networking.domain}
+      # to another host actually running the Matrix homeserver.
+      "${config.networking.domain}" = {
+        <link linkend="opt-services.nginx.virtualHosts._name_.locations._name_.extraConfig">locations."= /.well-known/matrix/server".extraConfig</link> =
+          let
+            # use 443 instead of the default 8448 port to unite
+            # the client-server and server-server port for simplicity
+            server = { "m.server" = "${fqdn}:443"; };
+          in ''
+            add_header Content-Type application/json;
+            return 200 '${builtins.toJSON server}';
+          '';
+        <link linkend="opt-services.nginx.virtualHosts._name_.locations._name_.extraConfig">locations."= /.well-known/matrix/client".extraConfig</link> =
+          let
+            client = {
+              "m.homeserver" =  { "base_url" = "https://${fqdn}"; };
+              "m.identity_server" =  { "base_url" = "https://vector.im"; };
+            };
+          # ACAO required to allow riot-web on any URL to request this json file
+          in ''
+            add_header Content-Type application/json;
+            add_header Access-Control-Allow-Origin *;
+            return 200 '${builtins.toJSON client}';
+          '';
+      };
+
+      # Reverse proxy for Matrix client-server and server-server communication
+      ${fqdn} = {
+        <link linkend="opt-services.nginx.virtualHosts._name_.enableACME">enableACME</link> = true;
+        <link linkend="opt-services.nginx.virtualHosts._name_.forceSSL">forceSSL</link> = true;
+
+        # Or do a redirect instead of the 404, or whatever is appropriate for you.
+        # But do not put a Matrix Web client here! See the Riot Web section below.
+        <link linkend="opt-services.nginx.virtualHosts._name_.locations._name_.extraConfig">locations."/".extraConfig</link> = ''
+          return 404;
+        '';
+
+        # forward all Matrix API calls to the synapse Matrix homeserver
+        locations."/_matrix" = {
+          <link linkend="opt-services.nginx.virtualHosts._name_.locations._name_.proxyPass">proxyPass</link> = "http://[::1]:8008"; # without a trailing /
+        };
+      };
+    };
+  };
+  services.matrix-synapse = {
+    <link linkend="opt-services.matrix-synapse.enable">enable</link> = true;
+    <link linkend="opt-services.matrix-synapse.server_name">server_name</link> = config.networking.domain;
+    <link linkend="opt-services.matrix-synapse.listeners">listeners</link> = [
+      {
+        <link linkend="opt-services.matrix-synapse.listeners._.port">port</link> = 8008;
+        <link linkend="opt-services.matrix-synapse.listeners._.bind_address">bind_address</link> = "::1";
+        <link linkend="opt-services.matrix-synapse.listeners._.type">type</link> = "http";
+        <link linkend="opt-services.matrix-synapse.listeners._.tls">tls</link> = false;
+        <link linkend="opt-services.matrix-synapse.listeners._.x_forwarded">x_forwarded</link> = true;
+        <link linkend="opt-services.matrix-synapse.listeners._.resources">resources</link> = [
+          {
+            <link linkend="opt-services.matrix-synapse.listeners._.resources._.names">names</link> = [ "client" "federation" ];
+            <link linkend="opt-services.matrix-synapse.listeners._.resources._.compress">compress</link> = false;
+          }
+        ];
+      }
+    ];
+  };
+};
+</programlisting>
+  </para>
+
+  <para>
+   If the <code>A</code> and <code>AAAA</code> DNS records on
+   <literal>example.org</literal> do not point on the same host as the records
+   for <code>myhostname.example.org</code>, you can easily move the
+   <code>/.well-known</code> virtualHost section of the code to the host that
+   is serving <literal>example.org</literal>, while the rest stays on
+   <literal>myhostname.example.org</literal> with no other changes required.
+   This pattern also allows to seamlessly move the homeserver from
+   <literal>myhostname.example.org</literal> to
+   <literal>myotherhost.example.org</literal> by only changing the
+   <code>/.well-known</code> redirection target.
+  </para>
+
+  <para>
+   If you want to run a server with public registration by anybody, you can
+   then enable <literal><link linkend="opt-services.matrix-synapse.enable_registration">services.matrix-synapse.enable_registration</link> =
+   true;</literal>. Otherwise, or you can generate a registration secret with
+   <command>pwgen -s 64 1</command> and set it with
+   <option><link linkend="opt-services.matrix-synapse.registration_shared_secret">services.matrix-synapse.registration_shared_secret</link></option>. To
+   create a new user or admin, run the following after you have set the secret
+   and have rebuilt NixOS:
+<screen>
+<prompt>$ </prompt>nix run nixpkgs.matrix-synapse
+<prompt>$ </prompt>register_new_matrix_user -k <replaceable>your-registration-shared-secret</replaceable> http://localhost:8008
+<prompt>New user localpart: </prompt><replaceable>your-username</replaceable>
+<prompt>Password:</prompt>
+<prompt>Confirm password:</prompt>
+<prompt>Make admin [no]:</prompt>
+Success!
+</screen>
+   In the example, this would create a user with the Matrix Identifier
+   <literal>@your-username:example.org</literal>. Note that the registration
+   secret ends up in the nix store and therefore is world-readable by any user
+   on your machine, so it makes sense to only temporarily activate the
+   <link linkend="opt-services.matrix-synapse.registration_shared_secret">registration_shared_secret</link>
+   option until a better solution for NixOS is in place.
+  </para>
+ </section>
+ <section xml:id="module-services-matrix-riot-web">
+  <title>Riot Web Client</title>
+
+  <para>
+   <link xlink:href="https://github.com/vector-im/riot-web/">Riot Web</link> is
+   the reference web client for Matrix and developed by the core team at
+   matrix.org. The following snippet can be optionally added to the code before
+   to complete the synapse installation with a web client served at
+   <code>https://riot.myhostname.example.org</code> and
+   <code>https://riot.example.org</code>. Alternatively, you can use the hosted
+   copy at <link xlink:href="https://riot.im/app">https://riot.im/app</link>,
+   or use other web clients or native client applications. Due to the
+   <literal>/.well-known</literal> urls set up done above, many clients should
+   fill in the required connection details automatically when you enter your
+   Matrix Identifier. See
+   <link xlink:href="https://matrix.org/docs/projects/try-matrix-now.html">Try
+   Matrix Now!</link> for a list of existing clients and their supported
+   featureset.
+<programlisting>
+{
+  services.nginx.virtualHosts."riot.${fqdn}" = {
+    <link linkend="opt-services.nginx.virtualHosts._name_.enableACME">enableACME</link> = true;
+    <link linkend="opt-services.nginx.virtualHosts._name_.forceSSL">forceSSL</link> = true;
+    <link linkend="opt-services.nginx.virtualHosts._name_.serverAliases">serverAliases</link> = [
+      "riot.${config.networking.domain}"
+    ];
+
+    <link linkend="opt-services.nginx.virtualHosts._name_.root">root</link> = pkgs.riot-web.override {
+      conf = {
+        default_server_config."m.homeserver" = {
+          "base_url" = "${config.networking.domain}";
+          "server_name" = "${fqdn}";
+        };
+      };
+    };
+  };
+}
+</programlisting>
+  </para>
+
+  <para>
+   Note that the Riot developers do not recommend running Riot and your Matrix
+   homeserver on the same fully-qualified domain name for security reasons. In
+   the example, this means that you should not reuse the
+   <literal>myhostname.example.org</literal> virtualHost to also serve Riot,
+   but instead serve it on a different subdomain, like
+   <literal>riot.example.org</literal> in the example. See the
+   <link xlink:href="https://github.com/vector-im/riot-web#important-security-note">Riot
+   Important Security Notes</link> for more information on this subject.
+  </para>
+ </section>
+</chapter>
diff --git a/nixos/modules/services/misc/nixos-manual.nix b/nixos/modules/services/misc/nixos-manual.nix
deleted file mode 100644
index ab73f49d4be..00000000000
--- a/nixos/modules/services/misc/nixos-manual.nix
+++ /dev/null
@@ -1,73 +0,0 @@
-# This module optionally starts a browser that shows the NixOS manual
-# on one of the virtual consoles which is useful for the installation
-# CD.
-
-{ config, lib, pkgs, ... }:
-
-with lib;
-
-let
-  cfg = config.services.nixosManual;
-  cfgd = config.documentation;
-in
-
-{
-
-  options = {
-
-    # TODO(@oxij): rename this to `.enable` eventually.
-    services.nixosManual.showManual = mkOption {
-      type = types.bool;
-      default = false;
-      description = ''
-        Whether to show the NixOS manual on one of the virtual
-        consoles.
-      '';
-    };
-
-    services.nixosManual.ttyNumber = mkOption {
-      type = types.int;
-      default = 8;
-      description = ''
-        Virtual console on which to show the manual.
-      '';
-    };
-
-    services.nixosManual.browser = mkOption {
-      type = types.path;
-      default = "${pkgs.w3m-nographics}/bin/w3m";
-      description = ''
-        Browser used to show the manual.
-      '';
-    };
-
-  };
-
-
-  config = mkMerge [
-    (mkIf cfg.showManual {
-      assertions = singleton {
-        assertion = cfgd.enable && cfgd.nixos.enable;
-        message   = "Can't enable `services.nixosManual.showManual` without `documentation.nixos.enable`";
-      };
-    })
-    (mkIf (cfg.showManual && cfgd.enable && cfgd.nixos.enable) {
-      console.extraTTYs = [ "tty${toString cfg.ttyNumber}" ];
-
-      systemd.services.nixos-manual = {
-        description = "NixOS Manual";
-        wantedBy = [ "multi-user.target" ];
-        serviceConfig = {
-          ExecStart = "${cfg.browser} ${config.system.build.manual.manualHTMLIndex}";
-          StandardInput = "tty";
-          StandardOutput = "tty";
-          TTYPath = "/dev/tty${toString cfg.ttyNumber}";
-          TTYReset = true;
-          TTYVTDisallocate = true;
-          Restart = "always";
-        };
-      };
-    })
-  ];
-
-}
diff --git a/nixos/modules/services/misc/parsoid.nix b/nixos/modules/services/misc/parsoid.nix
index 61626e78f8b..09b7f977bfb 100644
--- a/nixos/modules/services/misc/parsoid.nix
+++ b/nixos/modules/services/misc/parsoid.nix
@@ -6,7 +6,7 @@ let
 
   cfg = config.services.parsoid;
 
-  parsoid = pkgs.nodePackages."parsoid-git://github.com/abbradar/parsoid#stable";
+  parsoid = pkgs.nodePackages.parsoid;
 
   confTree = {
     worker_heartbeat_timeout = 300000;
@@ -98,8 +98,29 @@ in
       wantedBy = [ "multi-user.target" ];
       after = [ "network.target" ];
       serviceConfig = {
-        User = "nobody";
         ExecStart = "${parsoid}/lib/node_modules/parsoid/bin/server.js -c ${confFile} -n ${toString cfg.workers}";
+
+        DynamicUser = true;
+        User = "parsoid";
+        Group = "parsoid";
+
+        CapabilityBoundingSet = "";
+        NoNewPrivileges = true;
+        ProtectSystem = "strict";
+        ProtectHome = true;
+        PrivateTmp = true;
+        PrivateDevices = true;
+        ProtectHostname = true;
+        ProtectKernelTunables = true;
+        ProtectKernelModules = true;
+        ProtectControlGroups = true;
+        RestrictAddressFamilies = [ "AF_INET" "AF_INET6" ];
+        RestrictNamespaces = true;
+        LockPersonality = true;
+        #MemoryDenyWriteExecute = true;
+        RestrictRealtime = true;
+        RestrictSUIDSGID = true;
+        RemoveIPC = true;
       };
     };
 
diff --git a/nixos/modules/services/misc/rogue.nix b/nixos/modules/services/misc/rogue.nix
deleted file mode 100644
index d56d103b5f3..00000000000
--- a/nixos/modules/services/misc/rogue.nix
+++ /dev/null
@@ -1,62 +0,0 @@
-# Execute the game `rogue' on tty 9.  Mostly used by the NixOS
-# installation CD.
-
-{ config, lib, pkgs, ... }:
-
-with lib;
-
-let
-
-  cfg = config.services.rogue;
-
-in
-
-{
-  ###### interface
-
-  options = {
-
-    services.rogue.enable = mkOption {
-      type = types.bool;
-      default = false;
-      description = ''
-        Whether to enable the Rogue game on one of the virtual
-        consoles.
-      '';
-    };
-
-    services.rogue.tty = mkOption {
-      type = types.str;
-      default = "tty9";
-      description = ''
-        Virtual console on which to run Rogue.
-      '';
-    };
-
-  };
-
-
-  ###### implementation
-
-  config = mkIf cfg.enable {
-
-    console.extraTTYs = [ cfg.tty ];
-
-    systemd.services.rogue =
-      { description = "Rogue dungeon crawling game";
-        wantedBy = [ "multi-user.target" ];
-        serviceConfig =
-          { ExecStart = "${pkgs.rogue}/bin/rogue";
-            StandardInput = "tty";
-            StandardOutput = "tty";
-            TTYPath = "/dev/${cfg.tty}";
-            TTYReset = true;
-            TTYVTDisallocate = true;
-            WorkingDirectory = "/tmp";
-            Restart = "always";
-          };
-      };
-
-  };
-
-}
diff --git a/nixos/modules/services/misc/sssd.nix b/nixos/modules/services/misc/sssd.nix
index 6b64045dde8..36008d25741 100644
--- a/nixos/modules/services/misc/sssd.nix
+++ b/nixos/modules/services/misc/sssd.nix
@@ -88,9 +88,7 @@ in {
         exec ${pkgs.sssd}/bin/sss_ssh_authorizedkeys "$@"
       '';
     };
-    services.openssh.extraConfig = ''
-      AuthorizedKeysCommand /etc/ssh/authorized_keys_command
-      AuthorizedKeysCommandUser nobody
-    '';
+    services.openssh.authorizedKeysCommand = "/etc/ssh/authorized_keys_command";
+    services.openssh.authorizedKeysCommandUser = "nobody";
   })];
 }
diff --git a/nixos/modules/services/misc/zoneminder.nix b/nixos/modules/services/misc/zoneminder.nix
index d7f7324580c..d5b3537068d 100644
--- a/nixos/modules/services/misc/zoneminder.nix
+++ b/nixos/modules/services/misc/zoneminder.nix
@@ -77,6 +77,8 @@ in {
         `config.services.zoneminder.database.createLocally` to true. Otherwise,
         when set to `false` (the default), you will have to create the database
         and database user as well as populate the database yourself.
+        Additionally, you will need to run `zmupdate.pl` yourself when
+        upgrading to a newer version.
       '';
 
       webserver = mkOption {
@@ -330,6 +332,8 @@ in {
             ${config.services.mysql.package}/bin/mysql < ${pkg}/share/zoneminder/db/zm_create.sql
             touch "/var/lib/${dirName}/db-created"
           fi
+
+          ${zoneminder}/bin/zmupdate.pl -nointeractive
         '';
         serviceConfig = {
           User = user;
diff --git a/nixos/modules/services/monitoring/cadvisor.nix b/nixos/modules/services/monitoring/cadvisor.nix
index 695a8c42e85..655a6934a26 100644
--- a/nixos/modules/services/monitoring/cadvisor.nix
+++ b/nixos/modules/services/monitoring/cadvisor.nix
@@ -135,7 +135,6 @@ in {
 
         serviceConfig.TimeoutStartSec=300;
       };
-      virtualisation.docker.enable = mkDefault true;
     })
   ];
 }
diff --git a/nixos/modules/services/monitoring/graphite.nix b/nixos/modules/services/monitoring/graphite.nix
index dd147bb3793..64d9d61950d 100644
--- a/nixos/modules/services/monitoring/graphite.nix
+++ b/nixos/modules/services/monitoring/graphite.nix
@@ -39,8 +39,6 @@ let
     GRAPHITE_URL = cfg.seyren.graphiteUrl;
   } // cfg.seyren.extraConfig;
 
-  pagerConfig = pkgs.writeText "alarms.yaml" cfg.pager.alerts;
-
   configDir = pkgs.buildEnv {
     name = "graphite-config";
     paths = lists.filter (el: el != null) [
@@ -61,12 +59,10 @@ let
 
   carbonEnv = {
     PYTHONPATH = let
-      cenv = pkgs.python.buildEnv.override {
-        extraLibs = [ pkgs.python27Packages.carbon ];
+      cenv = pkgs.python3.buildEnv.override {
+        extraLibs = [ pkgs.python3Packages.carbon ];
       };
-      cenvPack =  "${cenv}/${pkgs.python.sitePackages}";
-    # opt/graphite/lib contains twisted.plugins.carbon-cache
-    in "${cenvPack}/opt/graphite/lib:${cenvPack}";
+    in "${cenv}/${pkgs.python3.sitePackages}";
     GRAPHITE_ROOT = dataDir;
     GRAPHITE_CONF_DIR = configDir;
     GRAPHITE_STORAGE_DIR = dataDir;
@@ -74,6 +70,10 @@ let
 
 in {
 
+  imports = [
+    (mkRemovedOptionModule ["services" "graphite" "pager"] "")
+  ];
+
   ###### interface
 
   options.services.graphite = {
@@ -132,7 +132,7 @@ in {
       finders = mkOption {
         description = "List of finder plugins to load.";
         default = [];
-        example = literalExample "[ pkgs.python27Packages.influxgraph ]";
+        example = literalExample "[ pkgs.python3Packages.influxgraph ]";
         type = types.listOf types.package;
       };
 
@@ -159,8 +159,8 @@ in {
 
       package = mkOption {
         description = "Package to use for graphite api.";
-        default = pkgs.python27Packages.graphite_api;
-        defaultText = "pkgs.python27Packages.graphite_api";
+        default = pkgs.python3Packages.graphite_api;
+        defaultText = "pkgs.python3Packages.graphite_api";
         type = types.package;
       };
 
@@ -344,49 +344,6 @@ in {
       };
     };
 
-    pager = {
-      enable = mkOption {
-        description = ''
-          Whether to enable graphite-pager service. For more information visit
-          <link xlink:href="https://github.com/seatgeek/graphite-pager"/>
-        '';
-        default = false;
-        type = types.bool;
-      };
-
-      redisUrl = mkOption {
-        description = "Redis connection string.";
-        default = "redis://localhost:${toString config.services.redis.port}/";
-        type = types.str;
-      };
-
-      graphiteUrl = mkOption {
-        description = "URL to your graphite service.";
-        default = "http://${cfg.web.listenAddress}:${toString cfg.web.port}";
-        type = types.str;
-      };
-
-      alerts = mkOption {
-        description = "Alerts configuration for graphite-pager.";
-        default = ''
-          alerts:
-            - target: constantLine(100)
-              warning: 90
-              critical: 200
-              name: Test
-        '';
-        example = ''
-          pushbullet_key: pushbullet_api_key
-          alerts:
-            - target: stats.seatgeek.app.deal_quality.venue_info_cache.hit
-              warning: .5
-              critical: 1
-              name: Deal quality venue cache hits
-        '';
-        type = types.lines;
-      };
-    };
-
     beacon = {
       enable = mkEnableOption "graphite beacon";
 
@@ -409,7 +366,7 @@ in {
         environment = carbonEnv;
         serviceConfig = {
           RuntimeDirectory = name;
-          ExecStart = "${pkgs.pythonPackages.twisted}/bin/twistd ${carbonOpts name}";
+          ExecStart = "${pkgs.python3Packages.twisted}/bin/twistd ${carbonOpts name}";
           User = "graphite";
           Group = "graphite";
           PermissionsStartOnly = true;
@@ -431,7 +388,7 @@ in {
         environment = carbonEnv;
         serviceConfig = {
           RuntimeDirectory = name;
-          ExecStart = "${pkgs.pythonPackages.twisted}/bin/twistd ${carbonOpts name}";
+          ExecStart = "${pkgs.python3Packages.twisted}/bin/twistd ${carbonOpts name}";
           User = "graphite";
           Group = "graphite";
           PIDFile="/run/${name}/${name}.pid";
@@ -447,7 +404,7 @@ in {
         environment = carbonEnv;
         serviceConfig = {
           RuntimeDirectory = name;
-          ExecStart = "${pkgs.pythonPackages.twisted}/bin/twistd ${carbonOpts name}";
+          ExecStart = "${pkgs.python3Packages.twisted}/bin/twistd ${carbonOpts name}";
           User = "graphite";
           Group = "graphite";
           PIDFile="/run/${name}/${name}.pid";
@@ -457,19 +414,11 @@ in {
 
     (mkIf (cfg.carbon.enableCache || cfg.carbon.enableAggregator || cfg.carbon.enableRelay) {
       environment.systemPackages = [
-        pkgs.pythonPackages.carbon
+        pkgs.python3Packages.carbon
       ];
     })
 
-    (mkIf cfg.web.enable (let
-      python27' = pkgs.python27.override {
-        packageOverrides = self: super: {
-          django = self.django_1_8;
-          django_tagging = self.django_tagging_0_4_3;
-        };
-      };
-      pythonPackages = python27'.pkgs;
-    in {
+    (mkIf cfg.web.enable ({
       systemd.services.graphiteWeb = {
         description = "Graphite Web Interface";
         wantedBy = [ "multi-user.target" ];
@@ -477,28 +426,27 @@ in {
         path = [ pkgs.perl ];
         environment = {
           PYTHONPATH = let
-              penv = pkgs.python.buildEnv.override {
+              penv = pkgs.python3.buildEnv.override {
                 extraLibs = [
-                  pythonPackages.graphite-web
-                  pythonPackages.pysqlite
+                  pkgs.python3Packages.graphite-web
                 ];
               };
-              penvPack = "${penv}/${pkgs.python.sitePackages}";
+              penvPack = "${penv}/${pkgs.python3.sitePackages}";
             in concatStringsSep ":" [
                  "${graphiteLocalSettingsDir}"
-                 "${penvPack}/opt/graphite/webapp"
                  "${penvPack}"
                  # explicitly adding pycairo in path because it cannot be imported via buildEnv
-                 "${pkgs.pythonPackages.pycairo}/${pkgs.python.sitePackages}"
+                 "${pkgs.python3Packages.pycairo}/${pkgs.python3.sitePackages}"
                ];
           DJANGO_SETTINGS_MODULE = "graphite.settings";
+          GRAPHITE_SETTINGS_MODULE = "graphite_local_settings";
           GRAPHITE_CONF_DIR = configDir;
           GRAPHITE_STORAGE_DIR = dataDir;
           LD_LIBRARY_PATH = "${pkgs.cairo.out}/lib";
         };
         serviceConfig = {
           ExecStart = ''
-            ${pkgs.python27Packages.waitress-django}/bin/waitress-serve-django \
+            ${pkgs.python3Packages.waitress-django}/bin/waitress-serve-django \
               --host=${cfg.web.listenAddress} --port=${toString cfg.web.port}
           '';
           User = "graphite";
@@ -510,7 +458,7 @@ in {
             mkdir -p ${dataDir}/{whisper/,log/webapp/}
             chmod 0700 ${dataDir}/{whisper/,log/webapp/}
 
-            ${pkgs.pythonPackages.django_1_8}/bin/django-admin.py migrate --noinput
+            ${pkgs.python3Packages.django}/bin/django-admin.py migrate --noinput
 
             chown -R graphite:graphite ${dataDir}
 
@@ -518,16 +466,16 @@ in {
           fi
 
           # Only collect static files when graphite_web changes.
-          if ! [ "${dataDir}/current_graphite_web" -ef "${pythonPackages.graphite-web}" ]; then
+          if ! [ "${dataDir}/current_graphite_web" -ef "${pkgs.python3Packages.graphite-web}" ]; then
             mkdir -p ${staticDir}
-            ${pkgs.pythonPackages.django_1_8}/bin/django-admin.py collectstatic  --noinput --clear
+            ${pkgs.python3Packages.django}/bin/django-admin.py collectstatic  --noinput --clear
             chown -R graphite:graphite ${staticDir}
-            ln -sfT "${pythonPackages.graphite-web}" "${dataDir}/current_graphite_web"
+            ln -sfT "${pkgs.python3Packages.graphite-web}" "${dataDir}/current_graphite_web"
           fi
         '';
       };
 
-      environment.systemPackages = [ pythonPackages.graphite-web ];
+      environment.systemPackages = [ pkgs.python3Packages.graphite-web ];
     }))
 
     (mkIf cfg.api.enable {
@@ -537,16 +485,16 @@ in {
         after = [ "network.target" ];
         environment = {
           PYTHONPATH = let
-              aenv = pkgs.python.buildEnv.override {
-                extraLibs = [ cfg.api.package pkgs.cairo pkgs.pythonPackages.cffi ] ++ cfg.api.finders;
+              aenv = pkgs.python3.buildEnv.override {
+                extraLibs = [ cfg.api.package pkgs.cairo pkgs.python3Packages.cffi ] ++ cfg.api.finders;
               };
-            in "${aenv}/${pkgs.python.sitePackages}";
+            in "${aenv}/${pkgs.python3.sitePackages}";
           GRAPHITE_API_CONFIG = graphiteApiConfig;
           LD_LIBRARY_PATH = "${pkgs.cairo.out}/lib";
         };
         serviceConfig = {
           ExecStart = ''
-            ${pkgs.python27Packages.waitress}/bin/waitress-serve \
+            ${pkgs.python3Packages.waitress}/bin/waitress-serve \
             --host=${cfg.api.listenAddress} --port=${toString cfg.api.port} \
             graphite_api.app:app
           '';
@@ -591,34 +539,13 @@ in {
       services.mongodb.enable = mkDefault true;
     })
 
-    (mkIf cfg.pager.enable {
-      systemd.services.graphitePager = {
-        description = "Graphite Pager Alerting Daemon";
-        wantedBy = [ "multi-user.target" ];
-        after = [ "network.target" "redis.service" ];
-        environment = {
-          REDIS_URL = cfg.pager.redisUrl;
-          GRAPHITE_URL = cfg.pager.graphiteUrl;
-        };
-        serviceConfig = {
-          ExecStart = "${pkgs.pythonPackages.graphitepager}/bin/graphite-pager --config ${pagerConfig}";
-          User = "graphite";
-          Group = "graphite";
-        };
-      };
-
-      services.redis.enable = mkDefault true;
-
-      environment.systemPackages = [ pkgs.pythonPackages.graphitepager ];
-    })
-
     (mkIf cfg.beacon.enable {
       systemd.services.graphite-beacon = {
         description = "Grpahite Beacon Alerting Daemon";
         wantedBy = [ "multi-user.target" ];
         serviceConfig = {
           ExecStart = ''
-            ${pkgs.pythonPackages.graphite_beacon}/bin/graphite-beacon \
+            ${pkgs.python3Packages.graphite_beacon}/bin/graphite-beacon \
               --config=${pkgs.writeText "graphite-beacon.json" (builtins.toJSON cfg.beacon.config)}
           '';
           User = "graphite";
@@ -630,7 +557,7 @@ in {
     (mkIf (
       cfg.carbon.enableCache || cfg.carbon.enableAggregator || cfg.carbon.enableRelay ||
       cfg.web.enable || cfg.api.enable ||
-      cfg.seyren.enable || cfg.pager.enable || cfg.beacon.enable
+      cfg.seyren.enable || cfg.beacon.enable
      ) {
       users.users.graphite = {
         uid = config.ids.uids.graphite;
diff --git a/nixos/modules/services/monitoring/netdata.nix b/nixos/modules/services/monitoring/netdata.nix
index f8225af2042..e43241eea89 100644
--- a/nixos/modules/services/monitoring/netdata.nix
+++ b/nixos/modules/services/monitoring/netdata.nix
@@ -9,10 +9,12 @@ let
     mkdir -p $out/libexec/netdata/plugins.d
     ln -s /run/wrappers/bin/apps.plugin $out/libexec/netdata/plugins.d/apps.plugin
     ln -s /run/wrappers/bin/freeipmi.plugin $out/libexec/netdata/plugins.d/freeipmi.plugin
+    ln -s /run/wrappers/bin/perf.plugin $out/libexec/netdata/plugins.d/perf.plugin
+    ln -s /run/wrappers/bin/slabinfo.plugin $out/libexec/netdata/plugins.d/slabinfo.plugin
   '';
 
   plugins = [
-    "${pkgs.netdata}/libexec/netdata/plugins.d"
+    "${cfg.package}/libexec/netdata/plugins.d"
     "${wrappedPlugins}/libexec/netdata/plugins.d"
   ] ++ cfg.extraPluginPaths;
 
@@ -35,6 +37,13 @@ in {
     services.netdata = {
       enable = mkEnableOption "netdata";
 
+      package = mkOption {
+        type = types.package;
+        default = pkgs.netdata;
+        defaultText = "pkgs.netdata";
+        description = "Netdata package to use.";
+      };
+
       user = mkOption {
         type = types.str;
         default = "netdata";
@@ -141,8 +150,8 @@ in {
       path = (with pkgs; [ curl gawk which ]) ++ lib.optional cfg.python.enable
         (pkgs.python3.withPackages cfg.python.extraPackages);
       serviceConfig = {
-        Environment="PYTHONPATH=${pkgs.netdata}/libexec/netdata/python.d/python_modules";
-        ExecStart = "${pkgs.netdata}/bin/netdata -P /run/netdata/netdata.pid -D -c ${configFile}";
+        Environment="PYTHONPATH=${cfg.package}/libexec/netdata/python.d/python_modules";
+        ExecStart = "${cfg.package}/bin/netdata -P /run/netdata/netdata.pid -D -c ${configFile}";
         ExecReload = "${pkgs.utillinux}/bin/kill -s HUP -s USR1 -s USR2 $MAINPID";
         TimeoutStopSec = 60;
         # User and group
@@ -159,7 +168,7 @@ in {
     systemd.enableCgroupAccounting = true;
 
     security.wrappers."apps.plugin" = {
-      source = "${pkgs.netdata}/libexec/netdata/plugins.d/apps.plugin.org";
+      source = "${cfg.package}/libexec/netdata/plugins.d/apps.plugin.org";
       capabilities = "cap_dac_read_search,cap_sys_ptrace+ep";
       owner = cfg.user;
       group = cfg.group;
@@ -167,13 +176,29 @@ in {
     };
 
     security.wrappers."freeipmi.plugin" = {
-      source = "${pkgs.netdata}/libexec/netdata/plugins.d/freeipmi.plugin.org";
+      source = "${cfg.package}/libexec/netdata/plugins.d/freeipmi.plugin.org";
       capabilities = "cap_dac_override,cap_fowner+ep";
       owner = cfg.user;
       group = cfg.group;
       permissions = "u+rx,g+rx,o-rwx";
     };
 
+    security.wrappers."perf.plugin" = {
+      source = "${cfg.package}/libexec/netdata/plugins.d/perf.plugin.org";
+      capabilities = "cap_sys_admin+ep";
+      owner = cfg.user;
+      group = cfg.group;
+      permissions = "u+rx,g+rx,o-rx";
+    };
+
+    security.wrappers."slabinfo.plugin" = {
+      source = "${cfg.package}/libexec/netdata/plugins.d/slabinfo.plugin.org";
+      capabilities = "cap_dac_override+ep";
+      owner = cfg.user;
+      group = cfg.group;
+      permissions = "u+rx,g+rx,o-rx";
+    };
+
     security.pam.loginLimits = [
       { domain = "netdata"; type = "soft"; item = "nofile"; value = "10000"; }
       { domain = "netdata"; type = "hard"; item = "nofile"; value = "30000"; }
diff --git a/nixos/modules/services/monitoring/prometheus/default.nix b/nixos/modules/services/monitoring/prometheus/default.nix
index b67f697ca0d..6b1a4be44d1 100644
--- a/nixos/modules/services/monitoring/prometheus/default.nix
+++ b/nixos/modules/services/monitoring/prometheus/default.nix
@@ -9,12 +9,13 @@ let
 
   # a wrapper that verifies that the configuration is valid
   promtoolCheck = what: name: file:
-    pkgs.runCommand
-      "${name}-${replaceStrings [" "] [""] what}-checked"
-      { buildInputs = [ cfg.package ]; } ''
-    ln -s ${file} $out
-    promtool ${what} $out
-  '';
+    if cfg.checkConfig then
+      pkgs.runCommand
+        "${name}-${replaceStrings [" "] [""] what}-checked"
+        { buildInputs = [ cfg.package ]; } ''
+      ln -s ${file} $out
+      promtool ${what} $out
+    '' else file;
 
   # Pretty-print JSON to a file
   writePrettyJSON = name: x:
@@ -601,6 +602,20 @@ in {
         if Prometheus is served via a reverse proxy).
       '';
     };
+
+    checkConfig = mkOption {
+      type = types.bool;
+      default = true;
+      description = ''
+        Check configuration with <literal>promtool
+        check</literal>. The call to <literal>promtool</literal> is
+        subject to sandboxing by Nix. When credentials are stored in
+        external files (<literal>password_file</literal>,
+        <literal>bearer_token_file</literal>, etc), they will not be
+        visible to <literal>promtool</literal> and it will report
+        errors, despite a correct configuration.
+      '';
+    };
   };
 
   config = mkIf cfg.enable {
diff --git a/nixos/modules/services/monitoring/prometheus/exporters.nix b/nixos/modules/services/monitoring/prometheus/exporters.nix
index 36ebffa4463..f9ad1457fc8 100644
--- a/nixos/modules/services/monitoring/prometheus/exporters.nix
+++ b/nixos/modules/services/monitoring/prometheus/exporters.nix
@@ -29,6 +29,7 @@ let
     "fritzbox"
     "json"
     "mail"
+    "mikrotik"
     "minio"
     "nextcloud"
     "nginx"
@@ -197,13 +198,25 @@ in
 
   config = mkMerge ([{
     assertions = [ {
-      assertion = (cfg.snmp.configurationPath == null) != (cfg.snmp.configuration == null);
+      assertion = cfg.snmp.enable -> (
+        (cfg.snmp.configurationPath == null) != (cfg.snmp.configuration == null)
+      );
       message = ''
         Please ensure you have either `services.prometheus.exporters.snmp.configuration'
           or `services.prometheus.exporters.snmp.configurationPath' set!
       '';
     } {
-      assertion = (cfg.mail.configFile == null) != (cfg.mail.configuration == {});
+      assertion = cfg.mikrotik.enable -> (
+        (cfg.mikrotik.configFile == null) != (cfg.mikrotik.configuration == null)
+      );
+      message = ''
+        Please specify either `services.prometheus.exporters.mikrotik.configuration'
+          or `services.prometheus.exporters.mikrotik.configFile'.
+      '';
+    } {
+      assertion = cfg.mail.enable -> (
+        (cfg.mail.configFile == null) != (cfg.mail.configuration == null)
+      );
       message = ''
         Please specify either 'services.prometheus.exporters.mail.configuration'
           or 'services.prometheus.exporters.mail.configFile'.
diff --git a/nixos/modules/services/monitoring/prometheus/exporters/blackbox.nix b/nixos/modules/services/monitoring/prometheus/exporters/blackbox.nix
index 8a90afa9984..fe8d905da3f 100644
--- a/nixos/modules/services/monitoring/prometheus/exporters/blackbox.nix
+++ b/nixos/modules/services/monitoring/prometheus/exporters/blackbox.nix
@@ -61,7 +61,7 @@ in {
       ExecStart = ''
         ${pkgs.prometheus-blackbox-exporter}/bin/blackbox_exporter \
           --web.listen-address ${cfg.listenAddress}:${toString cfg.port} \
-          --config.file ${adjustedConfigFile} \
+          --config.file ${escapeShellArg adjustedConfigFile} \
           ${concatStringsSep " \\\n  " cfg.extraFlags}
       '';
       ExecReload = "${pkgs.coreutils}/bin/kill -HUP $MAINPID";
diff --git a/nixos/modules/services/monitoring/prometheus/exporters/collectd.nix b/nixos/modules/services/monitoring/prometheus/exporters/collectd.nix
index 1cc34641809..97210463027 100644
--- a/nixos/modules/services/monitoring/prometheus/exporters/collectd.nix
+++ b/nixos/modules/services/monitoring/prometheus/exporters/collectd.nix
@@ -66,7 +66,7 @@ in
     serviceConfig = {
       ExecStart = ''
         ${pkgs.prometheus-collectd-exporter}/bin/collectd_exporter \
-          -log.format ${cfg.logFormat} \
+          -log.format ${escapeShellArg cfg.logFormat} \
           -log.level ${cfg.logLevel} \
           -web.listen-address ${cfg.listenAddress}:${toString cfg.port} \
           ${collectSettingsArgs} \
diff --git a/nixos/modules/services/monitoring/prometheus/exporters/dnsmasq.nix b/nixos/modules/services/monitoring/prometheus/exporters/dnsmasq.nix
index e9fa26cb1f5..68afba21d64 100644
--- a/nixos/modules/services/monitoring/prometheus/exporters/dnsmasq.nix
+++ b/nixos/modules/services/monitoring/prometheus/exporters/dnsmasq.nix
@@ -30,7 +30,7 @@ in
         ${pkgs.prometheus-dnsmasq-exporter}/bin/dnsmasq_exporter \
           --listen ${cfg.listenAddress}:${toString cfg.port} \
           --dnsmasq ${cfg.dnsmasqListenAddress} \
-          --leases_path ${cfg.leasesPath} \
+          --leases_path ${escapeShellArg cfg.leasesPath} \
           ${concatStringsSep " \\\n  " cfg.extraFlags}
       '';
     };
diff --git a/nixos/modules/services/monitoring/prometheus/exporters/dovecot.nix b/nixos/modules/services/monitoring/prometheus/exporters/dovecot.nix
index a01074758ff..aba3533e439 100644
--- a/nixos/modules/services/monitoring/prometheus/exporters/dovecot.nix
+++ b/nixos/modules/services/monitoring/prometheus/exporters/dovecot.nix
@@ -64,7 +64,7 @@ in
         ${pkgs.prometheus-dovecot-exporter}/bin/dovecot_exporter \
           --web.listen-address ${cfg.listenAddress}:${toString cfg.port} \
           --web.telemetry-path ${cfg.telemetryPath} \
-          --dovecot.socket-path ${cfg.socketPath} \
+          --dovecot.socket-path ${escapeShellArg cfg.socketPath} \
           --dovecot.scopes ${concatStringsSep "," cfg.scopes} \
           ${concatStringsSep " \\\n  " cfg.extraFlags}
       '';
diff --git a/nixos/modules/services/monitoring/prometheus/exporters/json.nix b/nixos/modules/services/monitoring/prometheus/exporters/json.nix
index 82a55bafc98..bd0026b55f7 100644
--- a/nixos/modules/services/monitoring/prometheus/exporters/json.nix
+++ b/nixos/modules/services/monitoring/prometheus/exporters/json.nix
@@ -27,7 +27,7 @@ in
       ExecStart = ''
         ${pkgs.prometheus-json-exporter}/bin/prometheus-json-exporter \
           --port ${toString cfg.port} \
-          ${cfg.url} ${cfg.configFile} \
+          ${cfg.url} ${escapeShellArg cfg.configFile} \
           ${concatStringsSep " \\\n  " cfg.extraFlags}
       '';
     };
diff --git a/nixos/modules/services/monitoring/prometheus/exporters/mail.nix b/nixos/modules/services/monitoring/prometheus/exporters/mail.nix
index 7d8c6fb6140..18c5c4dd162 100644
--- a/nixos/modules/services/monitoring/prometheus/exporters/mail.nix
+++ b/nixos/modules/services/monitoring/prometheus/exporters/mail.nix
@@ -90,7 +90,7 @@ let
         Timeout until mails are considered "didn't make it".
       '';
     };
-    disableFileDelition = mkOption {
+    disableFileDeletion = mkOption {
       type = types.bool;
       default = false;
       description = ''
@@ -127,8 +127,8 @@ in
       '';
     };
     configuration = mkOption {
-      type = types.submodule exporterOptions;
-      default = {};
+      type = types.nullOr (types.submodule exporterOptions);
+      default = null;
       description = ''
         Specify the mailexporter configuration file to use.
       '';
@@ -147,8 +147,9 @@ in
       ExecStart = ''
         ${pkgs.prometheus-mail-exporter}/bin/mailexporter \
           --web.listen-address ${cfg.listenAddress}:${toString cfg.port} \
+          --web.telemetry-path ${cfg.telemetryPath} \
           --config.file ${
-            if cfg.configuration != {} then configurationFile else cfg.configFile
+            if cfg.configuration != null then configurationFile else (escapeShellArg cfg.configFile)
           } \
           ${concatStringsSep " \\\n  " cfg.extraFlags}
       '';
diff --git a/nixos/modules/services/monitoring/prometheus/exporters/mikrotik.nix b/nixos/modules/services/monitoring/prometheus/exporters/mikrotik.nix
new file mode 100644
index 00000000000..62c2cc56847
--- /dev/null
+++ b/nixos/modules/services/monitoring/prometheus/exporters/mikrotik.nix
@@ -0,0 +1,66 @@
+{ config, lib, pkgs, options }:
+
+with lib;
+
+let
+  cfg = config.services.prometheus.exporters.mikrotik;
+in
+{
+  port = 9436;
+  extraOpts = {
+    configFile = mkOption {
+      type = types.nullOr types.path;
+      default = null;
+      description = ''
+        Path to a mikrotik exporter configuration file. Mutually exclusive with
+        <option>configuration</option> option.
+      '';
+      example = literalExample "./mikrotik.yml";
+    };
+
+    configuration = mkOption {
+      type = types.nullOr types.attrs;
+      default = null;
+      description = ''
+        Mikrotik exporter configuration as nix attribute set. Mutually exclusive with
+        <option>configFile</option> option.
+
+        See <link xlink:href="https://github.com/nshttpd/mikrotik-exporter/blob/master/README.md"/>
+        for the description of the configuration file format.
+      '';
+      example = literalExample ''
+        {
+          devices = [
+            {
+              name = "my_router";
+              address = "10.10.0.1";
+              user = "prometheus";
+              password = "changeme";
+            }
+          ];
+          features = {
+            bgp = true;
+            dhcp = true;
+            routes = true;
+            optics = true;
+          };
+        }
+      '';
+    };
+  };
+  serviceOpts = let
+    configFile = if cfg.configFile != null
+                 then cfg.configFile
+                 else "${pkgs.writeText "mikrotik-exporter.yml" (builtins.toJSON cfg.configuration)}";
+    in {
+    serviceConfig = {
+      # -port is misleading name, it actually accepts address too
+      ExecStart = ''
+        ${pkgs.prometheus-mikrotik-exporter}/bin/mikrotik-exporter \
+          -config-file=${escapeShellArg configFile} \
+          -port=${cfg.listenAddress}:${toString cfg.port} \
+          ${concatStringsSep " \\\n  " cfg.extraFlags}
+      '';
+    };
+  };
+}
diff --git a/nixos/modules/services/monitoring/prometheus/exporters/minio.nix b/nixos/modules/services/monitoring/prometheus/exporters/minio.nix
index ab3e3d7d5d5..d6dd62f871b 100644
--- a/nixos/modules/services/monitoring/prometheus/exporters/minio.nix
+++ b/nixos/modules/services/monitoring/prometheus/exporters/minio.nix
@@ -54,8 +54,8 @@ in
         ${pkgs.prometheus-minio-exporter}/bin/minio-exporter \
           -web.listen-address ${cfg.listenAddress}:${toString cfg.port} \
           -minio.server ${cfg.minioAddress} \
-          -minio.access-key ${cfg.minioAccessKey} \
-          -minio.access-secret ${cfg.minioAccessSecret} \
+          -minio.access-key ${escapeShellArg cfg.minioAccessKey} \
+          -minio.access-secret ${escapeShellArg cfg.minioAccessSecret} \
           ${optionalString cfg.minioBucketStats "-minio.bucket-stats"} \
           ${concatStringsSep " \\\n  " cfg.extraFlags}
       '';
diff --git a/nixos/modules/services/monitoring/prometheus/exporters/nextcloud.nix b/nixos/modules/services/monitoring/prometheus/exporters/nextcloud.nix
index 5f9a52053f7..aee6bd5e66c 100644
--- a/nixos/modules/services/monitoring/prometheus/exporters/nextcloud.nix
+++ b/nixos/modules/services/monitoring/prometheus/exporters/nextcloud.nix
@@ -50,7 +50,7 @@ in
           -u ${cfg.username} \
           -t ${cfg.timeout} \
           -l ${cfg.url} \
-          -p @${cfg.passwordFile} \
+          -p ${escapeShellArg "@${cfg.passwordFile}"} \
           ${concatStringsSep " \\\n  " cfg.extraFlags}
       '';
     };
diff --git a/nixos/modules/services/monitoring/prometheus/exporters/nginx.nix b/nixos/modules/services/monitoring/prometheus/exporters/nginx.nix
index ba852fea433..56cddfc55b7 100644
--- a/nixos/modules/services/monitoring/prometheus/exporters/nginx.nix
+++ b/nixos/modules/services/monitoring/prometheus/exporters/nginx.nix
@@ -30,7 +30,17 @@ in
         Whether to perform certificate verification for https.
       '';
     };
-
+    constLabels = mkOption {
+      type = types.listOf types.str;
+      default = [];
+      example = [
+        "label1=value1"
+        "label2=value2"
+      ];
+      description = ''
+        A list of constant labels that will be used in every metric.
+      '';
+    };
   };
   serviceOpts = {
     serviceConfig = {
@@ -40,6 +50,7 @@ in
           --nginx.ssl-verify ${toString cfg.sslVerify} \
           --web.listen-address ${cfg.listenAddress}:${toString cfg.port} \
           --web.telemetry-path ${cfg.telemetryPath} \
+          --prometheus.const-labels ${concatStringsSep "," cfg.constLabels} \
           ${concatStringsSep " \\\n  " cfg.extraFlags}
       '';
     };
diff --git a/nixos/modules/services/monitoring/prometheus/exporters/postfix.nix b/nixos/modules/services/monitoring/prometheus/exporters/postfix.nix
index d50564717ea..3b6ef1631f8 100644
--- a/nixos/modules/services/monitoring/prometheus/exporters/postfix.nix
+++ b/nixos/modules/services/monitoring/prometheus/exporters/postfix.nix
@@ -67,15 +67,15 @@ in
         ${pkgs.prometheus-postfix-exporter}/bin/postfix_exporter \
           --web.listen-address ${cfg.listenAddress}:${toString cfg.port} \
           --web.telemetry-path ${cfg.telemetryPath} \
-          --postfix.showq_path ${cfg.showqPath} \
+          --postfix.showq_path ${escapeShellArg cfg.showqPath} \
           ${concatStringsSep " \\\n  " (cfg.extraFlags
           ++ optional cfg.systemd.enable "--systemd.enable"
           ++ optional cfg.systemd.enable (if cfg.systemd.slice != null
                                           then "--systemd.slice ${cfg.systemd.slice}"
                                           else "--systemd.unit ${cfg.systemd.unit}")
           ++ optional (cfg.systemd.enable && (cfg.systemd.journalPath != null))
-                       "--systemd.journal_path ${cfg.systemd.journalPath}"
-          ++ optional (!cfg.systemd.enable) "--postfix.logfile_path ${cfg.logfilePath}")}
+                       "--systemd.journal_path ${escapeShellArg cfg.systemd.journalPath}"
+          ++ optional (!cfg.systemd.enable) "--postfix.logfile_path ${escapeShellArg cfg.logfilePath}")}
       '';
     };
   };
diff --git a/nixos/modules/services/monitoring/prometheus/exporters/snmp.nix b/nixos/modules/services/monitoring/prometheus/exporters/snmp.nix
index fe7ae8a8ac9..045e48a3d0f 100644
--- a/nixos/modules/services/monitoring/prometheus/exporters/snmp.nix
+++ b/nixos/modules/services/monitoring/prometheus/exporters/snmp.nix
@@ -19,7 +19,7 @@ in
 
     configuration = mkOption {
       type = types.nullOr types.attrs;
-      default = {};
+      default = null;
       description = ''
         Snmp exporter configuration as nix attribute set. Mutually exclusive with 'configurationPath' option.
       '';
@@ -36,15 +36,15 @@ in
     };
 
     logFormat = mkOption {
-      type = types.str;
-      default = "logger:stderr";
+      type = types.enum ["logfmt" "json"];
+      default = "logfmt";
       description = ''
-        Set the log target and format.
+        Output format of log messages.
       '';
     };
 
     logLevel = mkOption {
-      type = types.enum ["debug" "info" "warn" "error" "fatal"];
+      type = types.enum ["debug" "info" "warn" "error"];
       default = "info";
       description = ''
         Only log messages with the given severity or above.
@@ -54,13 +54,13 @@ in
   serviceOpts = let
     configFile = if cfg.configurationPath != null
                  then cfg.configurationPath
-                 else "${pkgs.writeText "snmp-eporter-conf.yml" (builtins.toJSON cfg.configuration)}";
+                 else "${pkgs.writeText "snmp-exporter-conf.yml" (builtins.toJSON cfg.configuration)}";
     in {
     serviceConfig = {
       ExecStart = ''
         ${pkgs.prometheus-snmp-exporter.bin}/bin/snmp_exporter \
-          --config.file=${configFile} \
-          --log.format=${cfg.logFormat} \
+          --config.file=${escapeShellArg configFile} \
+          --log.format=${escapeShellArg cfg.logFormat} \
           --log.level=${cfg.logLevel} \
           --web.listen-address=${cfg.listenAddress}:${toString cfg.port} \
           ${concatStringsSep " \\\n  " cfg.extraFlags}
diff --git a/nixos/modules/services/monitoring/prometheus/exporters/unifi.nix b/nixos/modules/services/monitoring/prometheus/exporters/unifi.nix
index 9aa0f1b85aa..8d0e8764001 100644
--- a/nixos/modules/services/monitoring/prometheus/exporters/unifi.nix
+++ b/nixos/modules/services/monitoring/prometheus/exporters/unifi.nix
@@ -55,8 +55,8 @@ in
         ${pkgs.prometheus-unifi-exporter}/bin/unifi_exporter \
           -telemetry.addr ${cfg.listenAddress}:${toString cfg.port} \
           -unifi.addr ${cfg.unifiAddress} \
-          -unifi.username ${cfg.unifiUsername} \
-          -unifi.password ${cfg.unifiPassword} \
+          -unifi.username ${escapeShellArg cfg.unifiUsername} \
+          -unifi.password ${escapeShellArg cfg.unifiPassword} \
           -unifi.timeout ${cfg.unifiTimeout} \
           ${optionalString cfg.unifiInsecure "-unifi.insecure" } \
           ${concatStringsSep " \\\n  " cfg.extraFlags}
diff --git a/nixos/modules/services/monitoring/prometheus/exporters/varnish.nix b/nixos/modules/services/monitoring/prometheus/exporters/varnish.nix
index 12153fa021e..5b5a6e18fcd 100644
--- a/nixos/modules/services/monitoring/prometheus/exporters/varnish.nix
+++ b/nixos/modules/services/monitoring/prometheus/exporters/varnish.nix
@@ -74,10 +74,10 @@ in
         ${pkgs.prometheus-varnish-exporter}/bin/prometheus_varnish_exporter \
           --web.listen-address ${cfg.listenAddress}:${toString cfg.port} \
           --web.telemetry-path ${cfg.telemetryPath} \
-          --varnishstat-path ${cfg.varnishStatPath} \
+          --varnishstat-path ${escapeShellArg cfg.varnishStatPath} \
           ${concatStringsSep " \\\n  " (cfg.extraFlags
             ++ optional (cfg.healthPath != null) "--web.health-path ${cfg.healthPath}"
-            ++ optional (cfg.instance != null) "-n ${cfg.instance}"
+            ++ optional (cfg.instance != null) "-n ${escapeShellArg cfg.instance}"
             ++ optional cfg.noExit "--no-exit"
             ++ optional cfg.withGoMetrics "--with-go-metrics"
             ++ optional cfg.verbose "--verbose"
diff --git a/nixos/modules/services/monitoring/prometheus/exporters/wireguard.nix b/nixos/modules/services/monitoring/prometheus/exporters/wireguard.nix
index 374f83a2939..04421fc2d25 100644
--- a/nixos/modules/services/monitoring/prometheus/exporters/wireguard.nix
+++ b/nixos/modules/services/monitoring/prometheus/exporters/wireguard.nix
@@ -59,7 +59,7 @@ in {
           ${optionalString cfg.verbose "-v"} \
           ${optionalString cfg.singleSubnetPerField "-s"} \
           ${optionalString cfg.withRemoteIp "-r"} \
-          ${optionalString (cfg.wireguardConfig != null) "-n ${cfg.wireguardConfig}"}
+          ${optionalString (cfg.wireguardConfig != null) "-n ${escapeShellArg cfg.wireguardConfig}"}
       '';
     };
   };
diff --git a/nixos/modules/services/networking/cjdns.nix b/nixos/modules/services/networking/cjdns.nix
index 3fb85b16cbe..5f8ac96b229 100644
--- a/nixos/modules/services/networking/cjdns.nix
+++ b/nixos/modules/services/networking/cjdns.nix
@@ -29,17 +29,13 @@ let
   };
 
   # Additional /etc/hosts entries for peers with an associated hostname
-  cjdnsExtraHosts = import (pkgs.runCommand "cjdns-hosts" {}
-    # Generate a builder that produces an output usable as a Nix string value
-    ''
-      exec >$out
-      echo \'\'
-      ${concatStringsSep "\n" (mapAttrsToList (k: v:
-          optionalString (v.hostname != "")
-            "echo $(${pkgs.cjdns}/bin/publictoip6 ${v.publicKey}) ${v.hostname}")
-          (cfg.ETHInterface.connectTo // cfg.UDPInterface.connectTo))}
-      echo \'\'
-    '');
+  cjdnsExtraHosts = pkgs.runCommandNoCC "cjdns-hosts" {} ''
+    exec >$out
+    ${concatStringsSep "\n" (mapAttrsToList (k: v:
+        optionalString (v.hostname != "")
+          "echo $(${pkgs.cjdns}/bin/publictoip6 ${v.publicKey}) ${v.hostname}")
+        (cfg.ETHInterface.connectTo // cfg.UDPInterface.connectTo))}
+  '';
 
   parseModules = x:
     x // { connectTo = mapAttrs (name: value: { inherit (value) password publicKey; }) x.connectTo; };
@@ -144,13 +140,15 @@ in
         connectTo = mkOption {
           type = types.attrsOf ( types.submodule ( connectToSubmodule ) );
           default = { };
-          example = {
-            "192.168.1.1:27313" = {
-              hostname = "homer.hype";
-              password = "5kG15EfpdcKNX3f2GSQ0H1HC7yIfxoCoImnO5FHM";
-              publicKey = "371zpkgs8ss387tmr81q04mp0hg1skb51hw34vk1cq644mjqhup0.k";
-            };
-          };
+          example = literalExample ''
+            {
+              "192.168.1.1:27313" = {
+                hostname = "homer.hype";
+                password = "5kG15EfpdcKNX3f2GSQ0H1HC7yIfxoCoImnO5FHM";
+                publicKey = "371zpkgs8ss387tmr81q04mp0hg1skb51hw34vk1cq644mjqhup0.k";
+              };
+            }
+          '';
           description = ''
             Credentials for making UDP tunnels.
           '';
@@ -189,13 +187,15 @@ in
         connectTo = mkOption {
           type = types.attrsOf ( types.submodule ( connectToSubmodule ) );
           default = { };
-          example = {
-            "01:02:03:04:05:06" = {
-              hostname = "homer.hype";
-              password = "5kG15EfpdcKNX3f2GSQ0H1HC7yIfxoCoImnO5FHM";
-              publicKey = "371zpkgs8ss387tmr81q04mp0hg1skb51hw34vk1cq644mjqhup0.k";
-            };
-          };
+          example = literalExample ''
+            {
+              "01:02:03:04:05:06" = {
+                hostname = "homer.hype";
+                password = "5kG15EfpdcKNX3f2GSQ0H1HC7yIfxoCoImnO5FHM";
+                publicKey = "371zpkgs8ss387tmr81q04mp0hg1skb51hw34vk1cq644mjqhup0.k";
+              };
+            }
+          '';
           description = ''
             Credentials for connecting look similar to UDP credientials
             except they begin with the mac address.
@@ -278,7 +278,7 @@ in
       };
     };
 
-    networking.extraHosts = mkIf cfg.addExtraHosts cjdnsExtraHosts;
+    networking.hostFiles = mkIf cfg.addExtraHosts [ cjdnsExtraHosts ];
 
     assertions = [
       { assertion = ( cfg.ETHInterface.bind != "" || cfg.UDPInterface.bind != "" || cfg.confFile != null );
diff --git a/nixos/modules/services/networking/dhcpcd.nix b/nixos/modules/services/networking/dhcpcd.nix
index f476b147a57..c0619211c2f 100644
--- a/nixos/modules/services/networking/dhcpcd.nix
+++ b/nixos/modules/services/networking/dhcpcd.nix
@@ -19,7 +19,7 @@ let
     map (i: i.name) (filter (i: if i.useDHCP != null then !i.useDHCP else i.ipv4.addresses != [ ]) interfaces)
     ++ mapAttrsToList (i: _: i) config.networking.sits
     ++ concatLists (attrValues (mapAttrs (n: v: v.interfaces) config.networking.bridges))
-    ++ concatLists (attrValues (mapAttrs (n: v: v.interfaces) config.networking.vswitches))
+    ++ flatten (concatMap (i: attrNames (filterAttrs (_: config: config.type != "internal") i.interfaces)) (attrValues config.networking.vswitches))
     ++ concatLists (attrValues (mapAttrs (n: v: v.interfaces) config.networking.bonds))
     ++ config.networking.dhcpcd.denyInterfaces;
 
diff --git a/nixos/modules/services/networking/firewall.nix b/nixos/modules/services/networking/firewall.nix
index 15aaf741067..cdc3a172ea7 100644
--- a/nixos/modules/services/networking/firewall.nix
+++ b/nixos/modules/services/networking/firewall.nix
@@ -546,9 +546,13 @@ in
       options nf_conntrack nf_conntrack_helper=1
     '';
 
-    assertions = [ { assertion = (cfg.checkReversePath != false) || kernelHasRPFilter;
-                     message = "This kernel does not support rpfilter"; }
-                 ];
+    assertions = [
+      # This is approximately "checkReversePath -> kernelHasRPFilter",
+      # but the checkReversePath option can include non-boolean
+      # values.
+      { assertion = cfg.checkReversePath == false || kernelHasRPFilter;
+        message = "This kernel does not support rpfilter"; }
+    ];
 
     systemd.services.firewall = {
       description = "Firewall";
diff --git a/nixos/modules/services/networking/freeradius.nix b/nixos/modules/services/networking/freeradius.nix
index e192b70c129..f3fdd576b65 100644
--- a/nixos/modules/services/networking/freeradius.nix
+++ b/nixos/modules/services/networking/freeradius.nix
@@ -10,14 +10,15 @@ let
   {
     description = "FreeRadius server";
     wantedBy = ["multi-user.target"];
-    after = ["network-online.target"];
-    wants = ["network-online.target"];
+    after = ["network.target"];
+    wants = ["network.target"];
     preStart = ''
       ${pkgs.freeradius}/bin/radiusd -C -d ${cfg.configDir} -l stdout
     '';
 
     serviceConfig = {
-        ExecStart = "${pkgs.freeradius}/bin/radiusd -f -d ${cfg.configDir} -l stdout -xx";
+        ExecStart = "${pkgs.freeradius}/bin/radiusd -f -d ${cfg.configDir} -l stdout" +
+                    optionalString cfg.debug " -xx";
         ExecReload = [
           "${pkgs.freeradius}/bin/radiusd -C -d ${cfg.configDir} -l stdout"
           "${pkgs.coreutils}/bin/kill -HUP $MAINPID"
@@ -41,6 +42,16 @@ let
       '';
     };
 
+    debug = mkOption {
+      type = types.bool;
+      default = false;
+      description = ''
+        Whether to enable debug logging for freeradius (-xx
+        option). This should not be left on, since it includes
+        sensitive data such as passwords in the logs.
+      '';
+    };
+
   };
 
 in
@@ -66,6 +77,7 @@ in
     };
 
     systemd.services.freeradius = freeradiusService cfg;
+    warnings = optional cfg.debug "Freeradius debug logging is enabled. This will log passwords in plaintext to the journal!";
 
   };
 
diff --git a/nixos/modules/services/networking/git-daemon.nix b/nixos/modules/services/networking/git-daemon.nix
index 6f2e149433f..52c895215fb 100644
--- a/nixos/modules/services/networking/git-daemon.nix
+++ b/nixos/modules/services/networking/git-daemon.nix
@@ -104,14 +104,14 @@ in
 
   config = mkIf cfg.enable {
 
-    users.users = optionalAttrs (cfg.user != "git") {
+    users.users = optionalAttrs (cfg.user == "git") {
       git = {
         uid = config.ids.uids.git;
         description = "Git daemon user";
       };
     };
 
-    users.groups = optionalAttrs (cfg.group != "git") {
+    users.groups = optionalAttrs (cfg.group == "git") {
       git.gid = config.ids.gids.git;
     };
 
diff --git a/nixos/modules/services/networking/haproxy.nix b/nixos/modules/services/networking/haproxy.nix
index aff71e5e97d..4678829986c 100644
--- a/nixos/modules/services/networking/haproxy.nix
+++ b/nixos/modules/services/networking/haproxy.nix
@@ -26,6 +26,18 @@ with lib;
         '';
       };
 
+      user = mkOption {
+        type = types.str;
+        default = "haproxy";
+        description = "User account under which haproxy runs.";
+      };
+
+      group = mkOption {
+        type = types.str;
+        default = "haproxy";
+        description = "Group account under which haproxy runs.";
+      };
+
       config = mkOption {
         type = types.nullOr types.lines;
         default = null;
@@ -49,7 +61,8 @@ with lib;
       after = [ "network.target" ];
       wantedBy = [ "multi-user.target" ];
       serviceConfig = {
-        DynamicUser = true;
+        User = cfg.user;
+        Group = cfg.group;
         Type = "notify";
         # when running the config test, don't be quiet so we can see what goes wrong
         ExecStartPre = "${pkgs.haproxy}/sbin/haproxy -c -f ${haproxyCfg}";
@@ -60,5 +73,16 @@ with lib;
         AmbientCapabilities = "CAP_NET_BIND_SERVICE";
       };
     };
+
+    users.users = optionalAttrs (cfg.user == "haproxy") {
+      haproxy = {
+        group = cfg.group;
+        isSystemUser = true;
+      };
+    };
+
+    users.groups = optionalAttrs (cfg.group == "haproxy") {
+      haproxy = {};
+    };
   };
 }
diff --git a/nixos/modules/services/networking/iodine.nix b/nixos/modules/services/networking/iodine.nix
index f9ca26c2796..46051d7044b 100644
--- a/nixos/modules/services/networking/iodine.nix
+++ b/nixos/modules/services/networking/iodine.nix
@@ -9,6 +9,8 @@ let
 
   iodinedUser = "iodined";
 
+  /* is this path made unreadable by ProtectHome = true ? */
+  isProtected = x: hasPrefix "/root" x || hasPrefix "/home" x;
 in
 {
   imports = [
@@ -35,45 +37,48 @@ in
           corresponding attribute name.
         '';
         example = literalExample ''
-        {
-          foo = {
-            server = "tunnel.mdomain.com";
-            relay = "8.8.8.8";
-            extraConfig = "-v";
+          {
+            foo = {
+              server = "tunnel.mdomain.com";
+              relay = "8.8.8.8";
+              extraConfig = "-v";
+            }
           }
-        }
         '';
-        type = types.attrsOf (types.submodule (
-        {
-          options = {
-            server = mkOption {
-              type = types.str;
-              default = "";
-              description = "Domain or Subdomain of server running iodined";
-              example = "tunnel.mydomain.com";
-            };
-
-            relay = mkOption {
-              type = types.str;
-              default = "";
-              description = "DNS server to use as a intermediate relay to the iodined server";
-              example = "8.8.8.8";
-            };
-
-            extraConfig = mkOption {
-              type = types.str;
-              default = "";
-              description = "Additional command line parameters";
-              example = "-l 192.168.1.10 -p 23";
-            };
-
-            passwordFile = mkOption {
-              type = types.str;
-              default = "";
-              description = "File that contains password";
-            };
-          };
-        }));
+        type = types.attrsOf (
+          types.submodule (
+            {
+              options = {
+                server = mkOption {
+                  type = types.str;
+                  default = "";
+                  description = "Hostname of server running iodined";
+                  example = "tunnel.mydomain.com";
+                };
+
+                relay = mkOption {
+                  type = types.str;
+                  default = "";
+                  description = "DNS server to use as an intermediate relay to the iodined server";
+                  example = "8.8.8.8";
+                };
+
+                extraConfig = mkOption {
+                  type = types.str;
+                  default = "";
+                  description = "Additional command line parameters";
+                  example = "-l 192.168.1.10 -p 23";
+                };
+
+                passwordFile = mkOption {
+                  type = types.str;
+                  default = "";
+                  description = "Path to a file containing the password.";
+                };
+              };
+            }
+          )
+        );
       };
 
       server = {
@@ -121,31 +126,67 @@ in
     boot.kernelModules = [ "tun" ];
 
     systemd.services =
-    let
-      createIodineClientService = name: cfg:
-      {
-        description = "iodine client - ${name}";
-        after = [ "network.target" ];
-        wantedBy = [ "multi-user.target" ];
-        script = "exec ${pkgs.iodine}/bin/iodine -f -u ${iodinedUser} ${cfg.extraConfig} ${optionalString (cfg.passwordFile != "") "< \"${cfg.passwordFile}\""} ${cfg.relay} ${cfg.server}";
-        serviceConfig = {
-          RestartSec = "30s";
-          Restart = "always";
+      let
+        createIodineClientService = name: cfg:
+          {
+            description = "iodine client - ${name}";
+            after = [ "network.target" ];
+            wantedBy = [ "multi-user.target" ];
+            script = "exec ${pkgs.iodine}/bin/iodine -f -u ${iodinedUser} ${cfg.extraConfig} ${optionalString (cfg.passwordFile != "") "< \"${builtins.toString cfg.passwordFile}\""} ${cfg.relay} ${cfg.server}";
+            serviceConfig = {
+              RestartSec = "30s";
+              Restart = "always";
+
+              # hardening :
+              # Filesystem access
+              ProtectSystem = "strict";
+              ProtectHome = if isProtected cfg.passwordFile then "read-only" else "true" ;
+              PrivateTmp = true;
+              ReadWritePaths = "/dev/net/tun";
+              PrivateDevices = false;
+              ProtectKernelTunables = true;
+              ProtectKernelModules = true;
+              ProtectControlGroups = true;
+              # Caps
+              NoNewPrivileges = true;
+              # Misc.
+              LockPersonality = true;
+              RestrictRealtime = true;
+              PrivateMounts = true;
+              MemoryDenyWriteExecute = true;
+            };
+          };
+      in
+        listToAttrs (
+          mapAttrsToList
+            (name: value: nameValuePair "iodine-${name}" (createIodineClientService name value))
+            cfg.clients
+        ) // {
+          iodined = mkIf (cfg.server.enable) {
+            description = "iodine, ip over dns server daemon";
+            after = [ "network.target" ];
+            wantedBy = [ "multi-user.target" ];
+            script = "exec ${pkgs.iodine}/bin/iodined -f -u ${iodinedUser} ${cfg.server.extraConfig} ${optionalString (cfg.server.passwordFile != "") "< \"${builtins.toString cfg.server.passwordFile}\""} ${cfg.server.ip} ${cfg.server.domain}";
+            serviceConfig = {
+              # Filesystem access
+              ProtectSystem = "strict";
+              ProtectHome = if isProtected cfg.server.passwordFile then "read-only" else "true" ;
+              PrivateTmp = true;
+              ReadWritePaths = "/dev/net/tun";
+              PrivateDevices = false;
+              ProtectKernelTunables = true;
+              ProtectKernelModules = true;
+              ProtectControlGroups = true;
+              # Caps
+              NoNewPrivileges = true;
+              # Misc.
+              LockPersonality = true;
+              RestrictRealtime = true;
+              PrivateMounts = true;
+              MemoryDenyWriteExecute = true;
+            };
+          };
         };
-      };
-    in
-    listToAttrs (
-      mapAttrsToList
-        (name: value: nameValuePair "iodine-${name}" (createIodineClientService name value))
-        cfg.clients
-    ) // {
-      iodined = mkIf (cfg.server.enable) {
-        description = "iodine, ip over dns server daemon";
-        after = [ "network.target" ];
-        wantedBy = [ "multi-user.target" ];
-        script = "exec ${pkgs.iodine}/bin/iodined -f -u ${iodinedUser} ${cfg.server.extraConfig} ${optionalString (cfg.server.passwordFile != "") "< \"${cfg.server.passwordFile}\""} ${cfg.server.ip} ${cfg.server.domain}";
-      };
-    };
 
     users.users.${iodinedUser} = {
       uid = config.ids.uids.iodined;
diff --git a/nixos/modules/services/networking/kresd.nix b/nixos/modules/services/networking/kresd.nix
index a2f91a4200b..c5a84eebd46 100644
--- a/nixos/modules/services/networking/kresd.nix
+++ b/nixos/modules/services/networking/kresd.nix
@@ -32,9 +32,9 @@ let
     + cfg.extraConfig
   );
 
-  package = pkgs.knot-resolver.override {
-    extraFeatures = cfg.listenDoH != [];
-  };
+  package = if cfg.listenDoH == []
+    then pkgs.knot-resolver # never force `extraFeatures = false`
+    else pkgs.knot-resolver.override { extraFeatures = true; };
 in {
   meta.maintainers = [ maintainers.vcunat /* upstream developer */ ];
 
diff --git a/nixos/modules/services/networking/nat.nix b/nixos/modules/services/networking/nat.nix
index 9c658af30f7..21ae9eb8b6d 100644
--- a/nixos/modules/services/networking/nat.nix
+++ b/nixos/modules/services/networking/nat.nix
@@ -65,7 +65,7 @@ let
         let
           m                = builtins.match "([0-9.]+):([0-9-]+)" fwd.destination;
           destinationIP    = if (m == null) then throw "bad ip:ports `${fwd.destination}'" else elemAt m 0;
-          destinationPorts = if (m == null) then throw "bad ip:ports `${fwd.destination}'" else elemAt m 1;
+          destinationPorts = if (m == null) then throw "bad ip:ports `${fwd.destination}'" else builtins.replaceStrings ["-"] [":"] (elemAt m 1);
         in ''
           # Allow connections to ${loopbackip}:${toString fwd.sourcePort} from the host itself
           iptables -w -t nat -A nixos-nat-out \
diff --git a/nixos/modules/services/networking/nix-store-gcs-proxy.nix b/nixos/modules/services/networking/nix-store-gcs-proxy.nix
new file mode 100644
index 00000000000..3f2ce5bca4d
--- /dev/null
+++ b/nixos/modules/services/networking/nix-store-gcs-proxy.nix
@@ -0,0 +1,75 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  opts = { name, config, ... }: {
+    options = {
+      enable = mkOption {
+        default = true;
+        type = types.bool;
+        example = true;
+        description = "Whether to enable proxy for this bucket";
+      };
+      bucketName = mkOption {
+        type = types.str;
+        default = name;
+        example = "my-bucket-name";
+        description = "Name of Google storage bucket";
+      };
+      address = mkOption {
+        type = types.str;
+        example = "localhost:3000";
+        description = "The address of the proxy.";
+      };
+    };
+  };
+  enabledProxies = lib.filterAttrs (n: v: v.enable) config.services.nix-store-gcs-proxy;
+  mapProxies = function: lib.mkMerge (lib.mapAttrsToList function enabledProxies);
+in
+{
+  options.services.nix-store-gcs-proxy = mkOption {
+    type = types.attrsOf (types.submodule opts);
+    default = {};
+    description = ''
+      An attribute set describing an HTTP to GCS proxy that allows us to use GCS
+      bucket via HTTP protocol.
+    '';
+  };
+
+  config.systemd.services = mapProxies (name: cfg: {
+    "nix-store-gcs-proxy-${name}" = {
+      description = "A HTTP nix store that proxies requests to Google Storage";
+      wantedBy = ["multi-user.target"];
+
+      serviceConfig = {
+        RestartSec = 5;
+        StartLimitInterval = 10;
+        ExecStart = ''
+          ${pkgs.nix-store-gcs-proxy}/bin/nix-store-gcs-proxy \
+            --bucket-name ${cfg.bucketName} \
+            --addr ${cfg.address}
+        '';
+
+        DynamicUser = true;
+
+        ProtectSystem = "strict";
+        ProtectHome = true;
+        PrivateTmp = true;
+        PrivateDevices = true;
+        PrivateMounts = true;
+        PrivateUsers = true;
+
+        ProtectKernelTunables = true;
+        ProtectKernelModules = true;
+        ProtectControlGroups = true;
+
+        NoNewPrivileges = true;
+        LockPersonality = true;
+        RestrictRealtime = true;
+      };
+    };
+  });
+
+  meta.maintainers = [ maintainers.mrkkrp ];
+}
diff --git a/nixos/modules/services/networking/ntp/ntpd.nix b/nixos/modules/services/networking/ntp/ntpd.nix
index b5403cb747d..54ff054d84c 100644
--- a/nixos/modules/services/networking/ntp/ntpd.nix
+++ b/nixos/modules/services/networking/ntp/ntpd.nix
@@ -23,6 +23,8 @@ let
     restrict -6 ::1
 
     ${toString (map (server: "server " + server + " iburst\n") cfg.servers)}
+
+    ${cfg.extraConfig}
   '';
 
   ntpFlags = "-c ${configFile} -u ${ntpUser}:nogroup ${toString cfg.extraFlags}";
@@ -81,6 +83,17 @@ in
         '';
       };
 
+      extraConfig = mkOption {
+        type = types.lines;
+        default = "";
+        example = ''
+          fudge 127.127.1.0 stratum 10
+        '';
+        description = ''
+          Additional text appended to <filename>ntp.conf</filename>.
+        '';
+      };
+
       extraFlags = mkOption {
         type = types.listOf types.str;
         description = "Extra flags passed to the ntpd command.";
diff --git a/nixos/modules/services/networking/resilio.nix b/nixos/modules/services/networking/resilio.nix
index 9b25aa57583..e74e03fc0b0 100644
--- a/nixos/modules/services/networking/resilio.nix
+++ b/nixos/modules/services/networking/resilio.nix
@@ -244,7 +244,7 @@ in
       group           = "rslsync";
     };
 
-    users.groups = [ { name = "rslsync"; } ];
+    users.groups.rslsync = {};
 
     systemd.services.resilio = with pkgs; {
       description = "Resilio Sync Service";
diff --git a/nixos/modules/services/networking/shorewall.nix b/nixos/modules/services/networking/shorewall.nix
index c59a5366915..16383be2530 100644
--- a/nixos/modules/services/networking/shorewall.nix
+++ b/nixos/modules/services/networking/shorewall.nix
@@ -26,13 +26,14 @@ in {
         description = "The shorewall package to use.";
       };
       configs = lib.mkOption {
-        type        = types.attrsOf types.str;
+        type        = types.attrsOf types.lines;
         default     = {};
         description = ''
           This option defines the Shorewall configs.
           The attribute name defines the name of the config,
           and the attribute value defines the content of the config.
         '';
+        apply = lib.mapAttrs (name: text: pkgs.writeText "${name}" text);
       };
     };
   };
@@ -62,7 +63,7 @@ in {
       '';
     };
     environment = {
-      etc = lib.mapAttrs' (name: conf: lib.nameValuePair "shorewall/${name}" {text=conf;}) cfg.configs;
+      etc = lib.mapAttrs' (name: conf: lib.nameValuePair "shorewall/${name}" {source=conf;}) cfg.configs;
       systemPackages = [ cfg.package ];
     };
   };
diff --git a/nixos/modules/services/networking/shorewall6.nix b/nixos/modules/services/networking/shorewall6.nix
index 374e407cc7a..e081aedc6c3 100644
--- a/nixos/modules/services/networking/shorewall6.nix
+++ b/nixos/modules/services/networking/shorewall6.nix
@@ -26,13 +26,14 @@ in {
         description = "The shorewall package to use.";
       };
       configs = lib.mkOption {
-        type        = types.attrsOf types.str;
+        type        = types.attrsOf types.lines;
         default     = {};
         description = ''
           This option defines the Shorewall configs.
           The attribute name defines the name of the config,
           and the attribute value defines the content of the config.
         '';
+        apply = lib.mapAttrs (name: text: pkgs.writeText "${name}" text);
       };
     };
   };
@@ -62,7 +63,7 @@ in {
       '';
     };
     environment = {
-      etc = lib.mapAttrs' (name: conf: lib.nameValuePair "shorewall6/${name}" {text=conf;}) cfg.configs;
+      etc = lib.mapAttrs' (name: conf: lib.nameValuePair "shorewall6/${name}" {source=conf;}) cfg.configs;
       systemPackages = [ cfg.package ];
     };
   };
diff --git a/nixos/modules/services/networking/smartdns.nix b/nixos/modules/services/networking/smartdns.nix
new file mode 100644
index 00000000000..f1888af7041
--- /dev/null
+++ b/nixos/modules/services/networking/smartdns.nix
@@ -0,0 +1,61 @@
+{ lib, pkgs, config, ... }:
+
+with lib;
+
+let
+  inherit (lib.types) attrsOf coercedTo listOf oneOf str int bool;
+  cfg = config.services.smartdns;
+
+  confFile = pkgs.writeText "smartdns.conf" (with generators;
+    toKeyValue {
+      mkKeyValue = mkKeyValueDefault {
+        mkValueString = v:
+          if isBool v then
+            if v then "yes" else "no"
+          else
+            mkValueStringDefault { } v;
+      } " ";
+      listsAsDuplicateKeys =
+        true; # Allowing duplications because we need to deal with multiple entries with the same key.
+    } cfg.settings);
+in {
+  options.services.smartdns = {
+    enable = mkEnableOption "SmartDNS DNS server";
+
+    bindPort = mkOption {
+      type = types.port;
+      default = 53;
+      description = "DNS listening port number.";
+    };
+
+    settings = mkOption {
+      type =
+      let atom = oneOf [ str int bool ];
+      in attrsOf (coercedTo atom toList (listOf atom));
+      example = literalExample ''
+        {
+          bind = ":5353 -no-rule -group example";
+          cache-size = 4096;
+          server-tls = [ "8.8.8.8:853" "1.1.1.1:853" ];
+          server-https = "https://cloudflare-dns.com/dns-query -exclude-default-group";
+          prefetch-domain = true;
+          speed-check-mode = "ping,tcp:80";
+        };
+      '';
+      description = ''
+        A set that will be generated into configuration file, see the <link xlink:href="https://github.com/pymumu/smartdns/blob/master/ReadMe_en.md#configuration-parameter">SmartDNS README</link> for details of configuration parameters.
+        You could override the options here like <option>services.smartdns.bindPort</option> by writing <literal>settings.bind = ":5353 -no-rule -group example";</literal>.
+      '';
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    services.smartdns.settings.bind = mkDefault ":${toString cfg.bindPort}";
+
+    systemd.packages = [ pkgs.smartdns ];
+    systemd.services.smartdns.wantedBy = [ "multi-user.target" ];
+    environment.etc."smartdns/smartdns.conf".source = confFile;
+    environment.etc."default/smartdns".source =
+      "${pkgs.smartdns}/etc/default/smartdns";
+  };
+}
diff --git a/nixos/modules/services/networking/ssh/sshd.nix b/nixos/modules/services/networking/ssh/sshd.nix
index b0e2e303cbc..464e9ed38c4 100644
--- a/nixos/modules/services/networking/ssh/sshd.nix
+++ b/nixos/modules/services/networking/ssh/sshd.nix
@@ -17,7 +17,7 @@ let
     ${cfg.extraConfig}
     EOL
 
-    ssh-keygen -f mock-hostkey -N ""
+    ssh-keygen -q -f mock-hostkey -N ""
     sshd -t -f $out -h mock-hostkey
   '';
 
@@ -238,6 +238,26 @@ in
         description = "Files from which authorized keys are read.";
       };
 
+      authorizedKeysCommand = mkOption {
+        type = types.str;
+        default = "none";
+        description = ''
+          Specifies a program to be used to look up the user's public
+          keys. The program must be owned by root, not writable by group
+          or others and specified by an absolute path.
+        '';
+      };
+
+      authorizedKeysCommandUser = mkOption {
+        type = types.str;
+        default = "nobody";
+        description = ''
+          Specifies the user under whose account the AuthorizedKeysCommand
+          is run. It is recommended to use a dedicated user that has no
+          other role on the host than running authorized keys commands.
+        '';
+      };
+
       kexAlgorithms = mkOption {
         type = types.listOf types.str;
         default = [
@@ -485,6 +505,10 @@ in
         PrintMotd no # handled by pam_motd
 
         AuthorizedKeysFile ${toString cfg.authorizedKeysFiles}
+        ${optionalString (cfg.authorizedKeysCommand != "none") ''
+          AuthorizedKeysCommand ${cfg.authorizedKeysCommand}
+          AuthorizedKeysCommandUser ${cfg.authorizedKeysCommandUser}
+        ''}
 
         ${flip concatMapStrings cfg.hostKeys (k: ''
           HostKey ${k.path}
diff --git a/nixos/modules/services/networking/sslh.nix b/nixos/modules/services/networking/sslh.nix
index 0222e8ce8b5..c4fa370a5fe 100644
--- a/nixos/modules/services/networking/sslh.nix
+++ b/nixos/modules/services/networking/sslh.nix
@@ -77,19 +77,14 @@ in
 
   config = mkMerge [
     (mkIf cfg.enable {
-      users.users.${user} = {
-        description = "sslh daemon user";
-        isSystemUser = true;
-      };
-
       systemd.services.sslh = {
         description = "Applicative Protocol Multiplexer (e.g. share SSH and HTTPS on the same port)";
         after = [ "network.target" ];
         wantedBy = [ "multi-user.target" ];
 
         serviceConfig = {
-          User                 = user;
-          Group                = "nogroup";
+          DynamicUser          = true;
+          User                 = "sslh";
           PermissionsStartOnly = true;
           Restart              = "always";
           RestartSec           = "1s";
diff --git a/nixos/modules/services/networking/stubby.nix b/nixos/modules/services/networking/stubby.nix
index b38bcd4cec0..c5e0f929a12 100644
--- a/nixos/modules/services/networking/stubby.nix
+++ b/nixos/modules/services/networking/stubby.nix
@@ -72,6 +72,7 @@ let
     resolution_type: GETDNS_RESOLUTION_STUB
     dns_transport_list:
       ${fallbacks}
+    appdata_dir: "/var/cache/stubby"
     tls_authentication: ${cfg.authenticationMode}
     tls_query_padding_blocksize: ${toString cfg.queryPaddingBlocksize}
     edns_client_subnet_private: ${if cfg.subnetPrivate then "1" else "0"}
@@ -204,10 +205,12 @@ in
       wantedBy = [ "multi-user.target" ];
 
       serviceConfig = {
+        Type = "notify";
         AmbientCapabilities = "CAP_NET_BIND_SERVICE";
         CapabilityBoundingSet = "CAP_NET_BIND_SERVICE";
         ExecStart = "${pkgs.stubby}/bin/stubby -C ${confFile} ${optionalString cfg.debugLogging "-l"}";
         DynamicUser = true;
+        CacheDirectory = "stubby";
       };
     };
   };
diff --git a/nixos/modules/services/networking/supplicant.nix b/nixos/modules/services/networking/supplicant.nix
index 35c1e649e2e..b5b9989ce18 100644
--- a/nixos/modules/services/networking/supplicant.nix
+++ b/nixos/modules/services/networking/supplicant.nix
@@ -39,8 +39,6 @@ let
         bindsTo = deps;
         after = deps;
         before = [ "network.target" ];
-        # Receive restart event after resume
-        partOf = [ "post-resume.target" ];
 
         path = [ pkgs.coreutils ];
 
diff --git a/nixos/modules/services/networking/supybot.nix b/nixos/modules/services/networking/supybot.nix
index d5b9a97a1c1..dc9fb31ffd0 100644
--- a/nixos/modules/services/networking/supybot.nix
+++ b/nixos/modules/services/networking/supybot.nix
@@ -3,32 +3,35 @@
 with lib;
 
 let
-
   cfg  = config.services.supybot;
-
+  isStateDirHome = hasPrefix "/home/" cfg.stateDir;
+  isStateDirVar = cfg.stateDir == "/var/lib/supybot";
+  pyEnv = pkgs.python3.withPackages (p: [ p.limnoria ] ++ (cfg.extraPackages p));
 in
-
 {
-
   options = {
 
     services.supybot = {
 
       enable = mkOption {
+        type = types.bool;
         default = false;
-        description = "Enable Supybot, an IRC bot";
+        description = "Enable Supybot, an IRC bot (also known as Limnoria).";
       };
 
       stateDir = mkOption {
-        # Setting this to /var/lib/supybot caused useradd to fail
-        default = "/home/supybot";
+        type = types.path;
+        default = if versionAtLeast config.system.stateVersion "20.09"
+          then "/var/lib/supybot"
+          else "/home/supybot";
+        defaultText = "/var/lib/supybot";
         description = "The root directory, logs and plugins are stored here";
       };
 
       configFile = mkOption {
         type = types.path;
         description = ''
-          Path to a supybot config file. This can be generated by
+          Path to initial supybot config file. This can be generated by
           running supybot-wizard.
 
           Note: all paths should include the full path to the stateDir
@@ -36,21 +39,54 @@ in
         '';
       };
 
+      plugins = mkOption {
+        type = types.attrsOf types.path;
+        default = {};
+        description = ''
+          Attribute set of additional plugins that will be symlinked to the
+          <filename>plugin</filename> subdirectory.
+
+          Please note that you still need to add the plugins to the config
+          file (or with <literal>!load</literal>) using their attribute name.
+        '';
+        example = literalExample ''
+          let
+            plugins = pkgs.fetchzip {
+              url = "https://github.com/ProgVal/Supybot-plugins/archive/57c2450c.zip";
+              sha256 = "077snf84ibnva3sbpzdfpfma6hcdw7dflwnhg6pw7mgnf0nd84qd";
+            };
+          in
+          {
+            Wikipedia = "''${plugins}/Wikipedia";
+            Decide = ./supy-decide;
+          }
+        '';
+      };
+
+      extraPackages = mkOption {
+        default = p: [];
+        description = ''
+          Extra Python packages available to supybot plugins. The
+          value must be a function which receives the attrset defined
+          in <varname>python3Packages</varname> as the sole argument.
+        '';
+        example = literalExample ''p: [ p.lxml p.requests ]'';
+      };
+
     };
 
   };
 
-
   config = mkIf cfg.enable {
 
-    environment.systemPackages = [ pkgs.pythonPackages.limnoria ];
+    environment.systemPackages = [ pkgs.python3Packages.limnoria ];
 
     users.users.supybot = {
       uid = config.ids.uids.supybot;
       group = "supybot";
       description = "Supybot IRC bot user";
       home = cfg.stateDir;
-      createHome = true;
+      isSystemUser = true;
     };
 
     users.groups.supybot = {
@@ -59,19 +95,16 @@ in
 
     systemd.services.supybot = {
       description = "Supybot, an IRC bot";
+      documentation = [ "https://limnoria.readthedocs.io/" ];
       after = [ "network.target" ];
       wantedBy = [ "multi-user.target" ];
-      path = [ pkgs.pythonPackages.limnoria ];
       preStart = ''
-        cd ${cfg.stateDir}
-        mkdir -p backup conf data plugins logs/plugins tmp web
-        ln -sf ${cfg.configFile} supybot.cfg
         # This needs to be created afresh every time
-        rm -f supybot.cfg.bak
+        rm -f '${cfg.stateDir}/supybot.cfg.bak'
       '';
 
       serviceConfig = {
-        ExecStart = "${pkgs.pythonPackages.limnoria}/bin/supybot ${cfg.stateDir}/supybot.cfg";
+        ExecStart = "${pyEnv}/bin/supybot ${cfg.stateDir}/supybot.cfg";
         PIDFile = "/run/supybot.pid";
         User = "supybot";
         Group = "supybot";
@@ -79,8 +112,50 @@ in
         Restart = "on-abort";
         StartLimitInterval = "5m";
         StartLimitBurst = "1";
+
+        NoNewPrivileges = true;
+        PrivateDevices = true;
+        PrivateMounts = true;
+        PrivateTmp = true;
+        ProtectControlGroups = true;
+        ProtectKernelModules = true;
+        ProtectKernelTunables = true;
+        RestrictAddressFamilies = [ "AF_INET" "AF_INET6" ];
+        RestrictSUIDSGID = true;
+        SystemCallArchitectures = "native";
+        RestrictNamespaces = true;
+        RestrictRealtime = true;
+        LockPersonality = true;
+        MemoryDenyWriteExecute = true;
+        RemoveIPC = true;
+        ProtectHostname = true;
+        CapabilityBoundingSet = "";
+        ProtectSystem = "full";
+      }
+      // optionalAttrs isStateDirVar {
+        StateDirectory = "supybot";
+        ProtectSystem = "strict";
+      }
+      // optionalAttrs (!isStateDirHome) {
+        ProtectHome = true;
       };
     };
 
+    systemd.tmpfiles.rules = [
+      "d '${cfg.stateDir}'              0700 supybot supybot - -"
+      "d '${cfg.stateDir}/backup'       0750 supybot supybot - -"
+      "d '${cfg.stateDir}/conf'         0750 supybot supybot - -"
+      "d '${cfg.stateDir}/data'         0750 supybot supybot - -"
+      "d '${cfg.stateDir}/plugins'      0750 supybot supybot - -"
+      "d '${cfg.stateDir}/logs'         0750 supybot supybot - -"
+      "d '${cfg.stateDir}/logs/plugins' 0750 supybot supybot - -"
+      "d '${cfg.stateDir}/tmp'          0750 supybot supybot - -"
+      "d '${cfg.stateDir}/web'          0750 supybot supybot - -"
+      "L '${cfg.stateDir}/supybot.cfg'  -    -       -       - ${cfg.configFile}"
+    ]
+    ++ (flip mapAttrsToList cfg.plugins (name: dest:
+      "L+ '${cfg.stateDir}/plugins/${name}' - - - - ${dest}"
+    ));
+
   };
 }
diff --git a/nixos/modules/services/networking/tailscale.nix b/nixos/modules/services/networking/tailscale.nix
new file mode 100644
index 00000000000..513c42b4011
--- /dev/null
+++ b/nixos/modules/services/networking/tailscale.nix
@@ -0,0 +1,46 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let cfg = config.services.tailscale;
+in {
+  meta.maintainers = with maintainers; [ danderson mbaillie ];
+
+  options.services.tailscale = {
+    enable = mkEnableOption "Tailscale client daemon";
+
+    port = mkOption {
+      type = types.port;
+      default = 41641;
+      description = "The port to listen on for tunnel traffic (0=autoselect).";
+    };
+  };
+
+  config = mkIf cfg.enable {
+    systemd.services.tailscale = {
+      description = "Tailscale client daemon";
+
+      after = [ "network-pre.target" ];
+      wants = [ "network-pre.target" ];
+      wantedBy = [ "multi-user.target" ];
+
+      unitConfig = {
+        StartLimitIntervalSec = 0;
+        StartLimitBurst = 0;
+      };
+
+      serviceConfig = {
+        ExecStart =
+          "${pkgs.tailscale}/bin/tailscaled --port ${toString cfg.port}";
+
+        RuntimeDirectory = "tailscale";
+        RuntimeDirectoryMode = 755;
+
+        StateDirectory = "tailscale";
+        StateDirectoryMode = 700;
+
+        Restart = "on-failure";
+      };
+    };
+  };
+}
diff --git a/nixos/modules/services/networking/vsftpd.nix b/nixos/modules/services/networking/vsftpd.nix
index 47990dbb377..b3e20184423 100644
--- a/nixos/modules/services/networking/vsftpd.nix
+++ b/nixos/modules/services/networking/vsftpd.nix
@@ -133,8 +133,8 @@ let
       ${optionalString cfg.enableVirtualUsers ''
         guest_enable=YES
         guest_username=vsftpd
-        pam_service_name=vsftpd
       ''}
+      pam_service_name=vsftpd
       ${cfg.extraConfig}
     '';
 
diff --git a/nixos/modules/services/networking/wireguard.nix b/nixos/modules/services/networking/wireguard.nix
index 7785861a730..e8f83f6dd8b 100644
--- a/nixos/modules/services/networking/wireguard.nix
+++ b/nixos/modules/services/networking/wireguard.nix
@@ -428,14 +428,14 @@ in
       ++ (attrValues (
         mapAttrs (name: value: {
           assertion = value.generatePrivateKeyFile -> (value.privateKey == null);
-          message = "networking.wireguard.interfaces.${name}.generatePrivateKey must not be set if networking.wireguard.interfaces.${name}.privateKey is set.";
+          message = "networking.wireguard.interfaces.${name}.generatePrivateKeyFile must not be set if networking.wireguard.interfaces.${name}.privateKey is set.";
         }) cfg.interfaces))
         ++ map ({ interfaceName, peer, ... }: {
           assertion = (peer.presharedKey == null) || (peer.presharedKeyFile == null);
           message = "networking.wireguard.interfaces.${interfaceName} peer «${peer.publicKey}» has both presharedKey and presharedKeyFile set, but only one can be used.";
         }) all_peers;
 
-    boot.extraModulePackages = [ kernel.wireguard ];
+    boot.extraModulePackages = optional (versionOlder kernel.kernel.version "5.6") kernel.wireguard;
     environment.systemPackages = [ pkgs.wireguard-tools ];
 
     systemd.services =
diff --git a/nixos/modules/services/networking/zerotierone.nix b/nixos/modules/services/networking/zerotierone.nix
index 069e15a909b..cf39ed065a7 100644
--- a/nixos/modules/services/networking/zerotierone.nix
+++ b/nixos/modules/services/networking/zerotierone.nix
@@ -67,5 +67,16 @@ in
     networking.firewall.allowedUDPPorts = [ cfg.port ];
 
     environment.systemPackages = [ cfg.package ];
+
+    # Prevent systemd from potentially changing the MAC address
+    systemd.network.links."50-zerotier" = {
+      matchConfig = {
+        OriginalName = "zt*";
+      };
+      linkConfig = {
+        AutoNegotiation = false;
+        MACAddressPolicy = "none";
+      };
+    };
   };
 }
diff --git a/nixos/modules/services/security/fail2ban.nix b/nixos/modules/services/security/fail2ban.nix
index cb748c93d24..3f84f9c2560 100644
--- a/nixos/modules/services/security/fail2ban.nix
+++ b/nixos/modules/services/security/fail2ban.nix
@@ -216,6 +216,10 @@ in
 
   config = mkIf cfg.enable {
 
+    warnings = mkIf (config.networking.firewall.enable == false && config.networking.nftables.enable == false) [
+      "fail2ban can not be used without a firewall"
+    ];
+
     environment.systemPackages = [ cfg.package ];
 
     environment.etc = {
diff --git a/nixos/modules/services/torrent/transmission.nix b/nixos/modules/services/torrent/transmission.nix
index 5ba72e8d773..fd28b94f7be 100644
--- a/nixos/modules/services/torrent/transmission.nix
+++ b/nixos/modules/services/torrent/transmission.nix
@@ -23,7 +23,8 @@ let
     for DIR in "${homeDir}" "${settingsDir}" "${fullSettings.download-dir}" "${fullSettings.incomplete-dir}"; do
       mkdir -p "$DIR"
     done
-    chmod 700 "${homeDir}" "${settingsDir}"
+    chmod 755 "${homeDir}"
+    chmod 700 "${settingsDir}"
     chmod ${downloadDirPermissions} "${fullSettings.download-dir}" "${fullSettings.incomplete-dir}"
     cp -f ${settingsFile} ${settingsDir}/settings.json
   '';
diff --git a/nixos/modules/services/wayland/cage.nix b/nixos/modules/services/wayland/cage.nix
new file mode 100644
index 00000000000..c59ca9983a6
--- /dev/null
+++ b/nixos/modules/services/wayland/cage.nix
@@ -0,0 +1,99 @@
+{ config, pkgs, lib, ... }:
+
+with lib;
+
+let
+  cfg = config.services.cage;
+in {
+  options.services.cage.enable = mkEnableOption "cage kiosk service";
+
+  options.services.cage.user = mkOption {
+    type = types.str;
+    default = "demo";
+    description = ''
+      User to log-in as.
+    '';
+  };
+
+  options.services.cage.extraArguments = mkOption {
+    type = types.listOf types.str;
+    default = [];
+    defaultText = "[]";
+    description = "Additional command line arguments to pass to Cage.";
+    example = ["-d"];
+  };
+
+  options.services.cage.program = mkOption {
+    type = types.path;
+    default = "${pkgs.xterm}/bin/xterm";
+    description = ''
+      Program to run in cage.
+    '';
+  };
+
+  config = mkIf cfg.enable {
+
+    # The service is partially based off of the one provided in the
+    # cage wiki at
+    # https://github.com/Hjdskes/cage/wiki/Starting-Cage-on-boot-with-systemd.
+    systemd.services."cage-tty1" = {
+      enable = true;
+      after = [
+        "systemd-user-sessions.service"
+        "plymouth-start.service"
+        "plymouth-quit.service"
+        "systemd-logind.service"
+        "getty@tty1.service"
+      ];
+      before = [ "graphical.target" ];
+      wants = [ "dbus.socket" "systemd-logind.service" "plymouth-quit.service"];
+      wantedBy = [ "graphical.target" ];
+      conflicts = [ "getty@tty1.service" ];
+
+      restartIfChanged = false;
+      unitConfig.ConditionPathExists = "/dev/tty1";
+      serviceConfig = {
+        ExecStart = ''
+          ${pkgs.cage}/bin/cage \
+            ${escapeShellArgs cfg.extraArguments} \
+            -- ${cfg.program}
+        '';
+        User = cfg.user;
+
+        IgnoreSIGPIPE = "no";
+
+        # Log this user with utmp, letting it show up with commands 'w' and
+        # 'who'. This is needed since we replace (a)getty.
+        UtmpIdentifier = "%n";
+        UtmpMode = "user";
+        # A virtual terminal is needed.
+        TTYPath = "/dev/tty1";
+        TTYReset = "yes";
+        TTYVHangup = "yes";
+        TTYVTDisallocate = "yes";
+        # Fail to start if not controlling the virtual terminal.
+        StandardInput = "tty-fail";
+        StandardOutput = "syslog";
+        StandardError = "syslog";
+        # Set up a full (custom) user session for the user, required by Cage.
+        PAMName = "cage";
+      };
+    };
+
+    security.pam.services.cage.text = ''
+      auth    required pam_unix.so nullok
+      account required pam_unix.so
+      session required pam_unix.so
+      session required ${pkgs.systemd}/lib/security/pam_systemd.so
+    '';
+
+    hardware.opengl.enable = mkDefault true;
+
+    systemd.targets.graphical.wants = [ "cage-tty1.service" ];
+
+    systemd.defaultUnit = "graphical.target";
+  };
+
+  meta.maintainers = with lib.maintainers; [ matthewbauer flokli ];
+
+}
diff --git a/nixos/modules/services/web-apps/codimd.nix b/nixos/modules/services/web-apps/codimd.nix
index 5f56f8ed5a0..751f81649dd 100644
--- a/nixos/modules/services/web-apps/codimd.nix
+++ b/nixos/modules/services/web-apps/codimd.nix
@@ -156,7 +156,7 @@ in
       };
       useCDN = mkOption {
         type = types.bool;
-        default = true;
+        default = false;
         description = ''
           Whether to use CDN resources or not.
         '';
diff --git a/nixos/modules/services/web-apps/gerrit.nix b/nixos/modules/services/web-apps/gerrit.nix
new file mode 100644
index 00000000000..b184c0754d4
--- /dev/null
+++ b/nixos/modules/services/web-apps/gerrit.nix
@@ -0,0 +1,218 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+let
+  cfg = config.services.gerrit;
+
+  # NixOS option type for git-like configs
+  gitIniType = with types;
+    let
+      primitiveType = either str (either bool int);
+      multipleType = either primitiveType (listOf primitiveType);
+      sectionType = lazyAttrsOf multipleType;
+      supersectionType = lazyAttrsOf (either multipleType sectionType);
+    in lazyAttrsOf supersectionType;
+
+  gerritConfig = pkgs.writeText "gerrit.conf" (
+    lib.generators.toGitINI cfg.settings
+  );
+
+  # Wrap the gerrit java with all the java options so it can be called
+  # like a normal CLI app
+  gerrit-cli = pkgs.writeShellScriptBin "gerrit" ''
+    set -euo pipefail
+    jvmOpts=(
+      ${lib.escapeShellArgs cfg.jvmOpts}
+      -Xmx${cfg.jvmHeapLimit}
+    )
+    exec ${cfg.jvmPackage}/bin/java \
+      "''${jvmOpts[@]}" \
+      -jar ${cfg.package}/webapps/${cfg.package.name}.war \
+      "$@"
+  '';
+
+  gerrit-plugins = pkgs.runCommand
+    "gerrit-plugins"
+    {
+      buildInputs = [ gerrit-cli ];
+    }
+    ''
+      shopt -s nullglob
+      mkdir $out
+
+      for name in ${toString cfg.builtinPlugins}; do
+        echo "Installing builtin plugin $name.jar"
+        gerrit cat plugins/$name.jar > $out/$name.jar
+      done
+
+      for file in ${toString cfg.plugins}; do
+        name=$(echo "$file" | cut -d - -f 2-)
+        echo "Installing plugin $name"
+        ln -sf "$file" $out/$name
+      done
+    '';
+in
+{
+  options = {
+    services.gerrit = {
+      enable = mkEnableOption "Gerrit service";
+
+      package = mkOption {
+        type = types.package;
+        default = pkgs.gerrit;
+        description = "Gerrit package to use";
+      };
+
+      jvmPackage = mkOption {
+        type = types.package;
+        default = pkgs.jre_headless;
+        defaultText = "pkgs.jre_headless";
+        description = "Java Runtime Environment package to use";
+      };
+
+      jvmOpts = mkOption {
+        type = types.listOf types.str;
+        default = [
+          "-Dflogger.backend_factory=com.google.common.flogger.backend.log4j.Log4jBackendFactory#getInstance"
+          "-Dflogger.logging_context=com.google.gerrit.server.logging.LoggingContext#getInstance"
+        ];
+        description = "A list of JVM options to start gerrit with.";
+      };
+
+      jvmHeapLimit = mkOption {
+        type = types.str;
+        default = "1024m";
+        description = ''
+          How much memory to allocate to the JVM heap
+        '';
+      };
+
+      listenAddress = mkOption {
+        type = types.str;
+        default = "[::]:8080";
+        description = ''
+          <literal>hostname:port</literal> to listen for HTTP traffic.
+
+          This is bound using the systemd socket activation.
+        '';
+      };
+
+      settings = mkOption {
+        type = gitIniType;
+        default = {};
+        description = ''
+          Gerrit configuration. This will be generated to the
+          <literal>etc/gerrit.config</literal> file.
+        '';
+      };
+
+      plugins = mkOption {
+        type = types.listOf types.package;
+        default = [];
+        description = ''
+          List of plugins to add to Gerrit. Each derivation is a jar file
+          itself where the name of the derivation is the name of plugin.
+        '';
+      };
+
+      builtinPlugins = mkOption {
+        type = types.listOf (types.enum cfg.package.passthru.plugins);
+        default = [];
+        description = ''
+          List of builtins plugins to install. Those are shipped in the
+          <literal>gerrit.war</literal> file.
+        '';
+      };
+
+      serverId = mkOption {
+        type = types.str;
+        description = ''
+          Set a UUID that uniquely identifies the server.
+
+          This can be generated with
+          <literal>nix-shell -p utillinux --run uuidgen</literal>.
+        '';
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+
+    services.gerrit.settings = {
+      cache.directory = "/var/cache/gerrit";
+      container.heapLimit = cfg.jvmHeapLimit;
+      gerrit.basePath = lib.mkDefault "git";
+      gerrit.serverId = cfg.serverId;
+      httpd.inheritChannel = "true";
+      httpd.listenUrl = lib.mkDefault "http://${cfg.listenAddress}";
+      index.type = lib.mkDefault "lucene";
+    };
+
+    # Add the gerrit CLI to the system to run `gerrit init` and friends.
+    environment.systemPackages = [ gerrit-cli ];
+
+    systemd.sockets.gerrit = {
+      unitConfig.Description = "Gerrit HTTP socket";
+      wantedBy = [ "sockets.target" ];
+      listenStreams = [ cfg.listenAddress ];
+    };
+
+    systemd.services.gerrit = {
+      description = "Gerrit";
+
+      wantedBy = [ "multi-user.target" ];
+      requires = [ "gerrit.socket" ];
+      after = [ "gerrit.socket" "network.target" ];
+
+      path = [
+        gerrit-cli
+        pkgs.bash
+        pkgs.coreutils
+        pkgs.git
+        pkgs.openssh
+      ];
+
+      environment = {
+        GERRIT_HOME = "%S/gerrit";
+        GERRIT_TMP = "%T";
+        HOME = "%S/gerrit";
+        XDG_CONFIG_HOME = "%S/gerrit/.config";
+      };
+
+      preStart = ''
+        set -euo pipefail
+
+        # bootstrap if nothing exists
+        if [[ ! -d git ]]; then
+          gerrit init --batch --no-auto-start
+        fi
+
+        # install gerrit.war for the plugin manager
+        rm -rf bin
+        mkdir bin
+        ln -sfv ${cfg.package}/webapps/${cfg.package.name}.war bin/gerrit.war
+
+        # copy the config, keep it mutable because Gerrit
+        ln -sfv ${gerritConfig} etc/gerrit.config
+
+        # install the plugins
+        rm -rf plugins
+        ln -sv ${gerrit-plugins} plugins
+      ''
+      ;
+
+      serviceConfig = {
+        CacheDirectory = "gerrit";
+        DynamicUser = true;
+        ExecStart = "${gerrit-cli}/bin/gerrit daemon --console-log";
+        LimitNOFILE = 4096;
+        StandardInput = "socket";
+        StandardOutput = "journal";
+        StateDirectory = "gerrit";
+        WorkingDirectory = "%S/gerrit";
+      };
+    };
+  };
+
+  meta.maintainers = with lib.maintainers; [ edef zimbatm ];
+}
diff --git a/nixos/modules/services/web-apps/nextcloud.nix b/nixos/modules/services/web-apps/nextcloud.nix
index d79f2bb735f..087bd0e5df3 100644
--- a/nixos/modules/services/web-apps/nextcloud.nix
+++ b/nixos/modules/services/web-apps/nextcloud.nix
@@ -30,7 +30,7 @@ let
 
   occ = pkgs.writeScriptBin "nextcloud-occ" ''
     #! ${pkgs.stdenv.shell}
-    cd ${pkgs.nextcloud}
+    cd ${cfg.package}
     sudo=exec
     if [[ "$USER" != nextcloud ]]; then
       sudo='exec /run/wrappers/bin/sudo -u nextcloud --preserve-env=NEXTCLOUD_CONFIG_DIR'
@@ -42,6 +42,8 @@ let
       occ $*
   '';
 
+  inherit (config.system) stateVersion;
+
 in {
   options.services.nextcloud = {
     enable = mkEnableOption "nextcloud";
@@ -64,6 +66,11 @@ in {
       default = false;
       description = "Use https for generated links.";
     };
+    package = mkOption {
+      type = types.package;
+      description = "Which package to use for the Nextcloud instance.";
+      relatedPackages = [ "nextcloud17" "nextcloud18" ];
+    };
 
     maxUploadSize = mkOption {
       default = "512M";
@@ -309,10 +316,31 @@ in {
         }
       ];
 
-      warnings = optional (cfg.poolConfig != null) ''
-        Using config.services.nextcloud.poolConfig is deprecated and will become unsupported in a future release.
-        Please migrate your configuration to config.services.nextcloud.poolSettings.
-      '';
+      warnings = []
+        ++ (optional (cfg.poolConfig != null) ''
+          Using config.services.nextcloud.poolConfig is deprecated and will become unsupported in a future release.
+          Please migrate your configuration to config.services.nextcloud.poolSettings.
+        '')
+        ++ (optional (versionOlder cfg.package.version "18") ''
+          You're currently deploying an older version of Nextcloud. This may be needed
+          since Nextcloud doesn't allow major version upgrades across multiple versions (i.e. an
+          upgrade from 16 is possible to 17, but not to 18).
+
+          Please deploy this to your server and wait until the migration is finished. After
+          that you can deploy to the latest Nextcloud version available.
+        '');
+
+      services.nextcloud.package = with pkgs;
+        mkDefault (
+          if pkgs ? nextcloud
+            then throw ''
+              The `pkgs.nextcloud`-attribute has been removed. If it's supposed to be the default
+              nextcloud defined in an overlay, please set `services.nextcloud.package` to
+              `pkgs.nextcloud`.
+            ''
+          else if versionOlder stateVersion "20.03" then nextcloud17
+          else nextcloud18
+        );
     }
 
     { systemd.timers.nextcloud-cron = {
@@ -407,7 +435,7 @@ in {
           path = [ occ ];
           script = ''
             chmod og+x ${cfg.home}
-            ln -sf ${pkgs.nextcloud}/apps ${cfg.home}/
+            ln -sf ${cfg.package}/apps ${cfg.home}/
             mkdir -p ${cfg.home}/config ${cfg.home}/data ${cfg.home}/store-apps
             ln -sf ${overrideConfig} ${cfg.home}/config/override.config.php
 
@@ -429,7 +457,7 @@ in {
           environment.NEXTCLOUD_CONFIG_DIR = "${cfg.home}/config";
           serviceConfig.Type = "oneshot";
           serviceConfig.User = "nextcloud";
-          serviceConfig.ExecStart = "${phpPackage}/bin/php -f ${pkgs.nextcloud}/cron.php";
+          serviceConfig.ExecStart = "${phpPackage}/bin/php -f ${cfg.package}/cron.php";
         };
         nextcloud-update-plugins = mkIf cfg.autoUpdateApps.enable {
           serviceConfig.Type = "oneshot";
@@ -443,7 +471,7 @@ in {
         pools.nextcloud = {
           user = "nextcloud";
           group = "nginx";
-          phpOptions = phpOptionsExtensions + phpOptionsStr;
+          phpOptions = phpOptionsStr;
           phpPackage = phpPackage;
           phpEnv = {
             NEXTCLOUD_CONFIG_DIR = "${cfg.home}/config";
@@ -471,7 +499,7 @@ in {
         enable = true;
         virtualHosts = {
           ${cfg.hostName} = {
-            root = pkgs.nextcloud;
+            root = cfg.package;
             locations = {
               "= /robots.txt" = {
                 priority = 100;
@@ -533,6 +561,7 @@ in {
                 add_header X-Robots-Tag none;
                 add_header X-Download-Options noopen;
                 add_header X-Permitted-Cross-Domain-Policies none;
+                add_header X-Frame-Options sameorigin;
                 add_header Referrer-Policy no-referrer;
                 access_log off;
               '';
@@ -547,6 +576,7 @@ in {
               add_header X-Robots-Tag none;
               add_header X-Download-Options noopen;
               add_header X-Permitted-Cross-Domain-Policies none;
+              add_header X-Frame-Options sameorigin;
               add_header Referrer-Policy no-referrer;
               add_header Strict-Transport-Security "max-age=15552000; includeSubDomains" always;
               error_page 403 /core/templates/403.php;
diff --git a/nixos/modules/services/web-apps/nextcloud.xml b/nixos/modules/services/web-apps/nextcloud.xml
index d66e0f0c299..fc454f8ba25 100644
--- a/nixos/modules/services/web-apps/nextcloud.xml
+++ b/nixos/modules/services/web-apps/nextcloud.xml
@@ -113,5 +113,53 @@
    maintenance:install</literal>! This command tries to install the application
    and can cause unwanted side-effects!</para>
   </warning>
+
+  <para>
+   Nextcloud doesn't allow to move more than one major-version forward. If you're e.g. on
+   <literal>v16</literal>, you cannot upgrade to <literal>v18</literal>, you need to upgrade to
+   <literal>v17</literal> first. This is ensured automatically as long as the
+   <link linkend="opt-system.stateVersion">stateVersion</link> is declared properly. In that case
+   the oldest version available (one major behind the one from the previous NixOS
+   release) will be selected by default and the module will generate a warning that reminds
+   the user to upgrade to latest Nextcloud <emphasis>after</emphasis> that deploy.
+  </para>
+ </section>
+
+ <section xml:id="module-services-nextcloud-maintainer-info">
+  <title>Maintainer information</title>
+
+  <para>
+   As stated in the previous paragraph, we must provide a clean upgrade-path for Nextcloud
+   since it cannot move more than one major version forward on a single upgrade. This chapter
+   adds some notes how Nextcloud updates should be rolled out in the future.
+  </para>
+
+  <para>
+   While minor and patch-level updates are no problem and can be done directly in the
+   package-expression (and should be backported to supported stable branches after that),
+   major-releases should be added in a new attribute (e.g. Nextcloud <literal>v19.0.0</literal>
+   should be available in <literal>nixpkgs</literal> as <literal>pkgs.nextcloud19</literal>).
+   To provide simple upgrade paths it's generally useful to backport those as well to stable
+   branches. As long as the package-default isn't altered, this won't break existing setups.
+   After that, the versioning-warning in the <literal>nextcloud</literal>-module should be
+   updated to make sure that the
+   <link linkend="opt-services.nextcloud.package">package</link>-option selects the latest version
+   on fresh setups.
+  </para>
+
+  <para>
+   If major-releases will be abandoned by upstream, we should check first if those are needed
+   in NixOS for a safe upgrade-path before removing those. In that case we shold keep those
+   packages, but mark them as insecure in an expression like this (in
+   <literal>&lt;nixpkgs/pkgs/servers/nextcloud/default.nix&gt;</literal>):
+<programlisting>/* ... */
+{
+  nextcloud17 = generic {
+    version = "17.0.x";
+    sha256 = "0000000000000000000000000000000000000000000000000000";
+    insecure = true;
+  };
+}</programlisting>
+  </para>
  </section>
 </chapter>
diff --git a/nixos/modules/services/web-servers/nginx/default.nix b/nixos/modules/services/web-servers/nginx/default.nix
index c8602e5975b..28b433104a1 100644
--- a/nixos/modules/services/web-servers/nginx/default.nix
+++ b/nixos/modules/services/web-servers/nginx/default.nix
@@ -87,10 +87,17 @@ let
       ${optionalString (cfg.sslDhparam != null) "ssl_dhparam ${cfg.sslDhparam};"}
 
       ${optionalString (cfg.recommendedTlsSettings) ''
-        ssl_session_cache shared:SSL:42m;
-        ssl_session_timeout 23m;
-        ssl_ecdh_curve secp384r1;
-        ssl_prefer_server_ciphers on;
+        # Keep in sync with https://ssl-config.mozilla.org/#server=nginx&config=intermediate
+
+        ssl_session_timeout 1d;
+        ssl_session_cache shared:SSL:10m;
+        # Breaks forward secrecy: https://github.com/mozilla/server-side-tls/issues/135
+        ssl_session_tickets off;
+        # We don't enable insecure ciphers by default, so this allows
+        # clients to pick the most performant, per https://github.com/mozilla/server-side-tls/issues/260
+        ssl_prefer_server_ciphers off;
+
+        # OCSP stapling
         ssl_stapling on;
         ssl_stapling_verify on;
       ''}
@@ -487,8 +494,9 @@ in
 
       sslCiphers = mkOption {
         type = types.str;
-        default = "EECDH+aRSA+AESGCM:EDH+aRSA:EECDH+aRSA:+AES256:+AES128:+SHA1:!CAMELLIA:!SEED:!3DES:!DES:!RC4:!eNULL";
-        description = "Ciphers to choose from when negotiating tls handshakes.";
+        # Keep in sync with https://ssl-config.mozilla.org/#server=nginx&config=intermediate
+        default = "ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384";
+        description = "Ciphers to choose from when negotiating TLS handshakes.";
       };
 
       sslProtocols = mkOption {
diff --git a/nixos/modules/services/web-servers/uwsgi.nix b/nixos/modules/services/web-servers/uwsgi.nix
index 3481b5e6040..4b74c329e3d 100644
--- a/nixos/modules/services/web-servers/uwsgi.nix
+++ b/nixos/modules/services/web-servers/uwsgi.nix
@@ -32,7 +32,7 @@ let
               inherit plugins;
             } // removeAttrs c [ "type" "pythonPackages" ]
               // optionalAttrs (python != null) {
-                pythonpath = "${pythonEnv}/${python.sitePackages}";
+                pyhome = "${pythonEnv}";
                 env =
                   # Argh, uwsgi expects list of key-values there instead of a dictionary.
                   let env' = c.env or [];
diff --git a/nixos/modules/services/x11/desktop-managers/kodi.nix b/nixos/modules/services/x11/desktop-managers/kodi.nix
index 65a7b9c628e..e997b9a1134 100644
--- a/nixos/modules/services/x11/desktop-managers/kodi.nix
+++ b/nixos/modules/services/x11/desktop-managers/kodi.nix
@@ -20,7 +20,7 @@ in
     services.xserver.desktopManager.session = [{
       name = "kodi";
       start = ''
-        ${pkgs.kodi}/bin/kodi --lircdev /run/lirc/lircd --standalone &
+        LIRC_SOCKET_PATH=/run/lirc/lircd ${pkgs.kodi}/bin/kodi --standalone &
         waitPID=$!
       '';
     }];
diff --git a/nixos/modules/services/x11/desktop-managers/mate.nix b/nixos/modules/services/x11/desktop-managers/mate.nix
index 910a246d776..f236c14fcf3 100644
--- a/nixos/modules/services/x11/desktop-managers/mate.nix
+++ b/nixos/modules/services/x11/desktop-managers/mate.nix
@@ -44,35 +44,35 @@ in
 
   config = mkIf cfg.enable {
 
-    services.xserver.desktopManager.session = singleton {
-      name = "mate";
-      bgSupport = true;
-      start = ''
-        export XDG_MENU_PREFIX=mate-
+    services.xserver.displayManager.sessionPackages = [
+      pkgs.mate.mate-session-manager
+    ];
 
-        # Let caja find extensions
-        export CAJA_EXTENSION_DIRS=$CAJA_EXTENSION_DIRS''${CAJA_EXTENSION_DIRS:+:}${config.system.path}/lib/caja/extensions-2.0
+    services.xserver.displayManager.sessionCommands = ''
+      if test "$XDG_CURRENT_DESKTOP" = "MATE"; then
+          export XDG_MENU_PREFIX=mate-
 
-        # Let caja extensions find gsettings schemas
-        ${concatMapStrings (p: ''
+          # Let caja find extensions
+          export CAJA_EXTENSION_DIRS=$CAJA_EXTENSION_DIRS''${CAJA_EXTENSION_DIRS:+:}${config.system.path}/lib/caja/extensions-2.0
+
+          # Let caja extensions find gsettings schemas
+          ${concatMapStrings (p: ''
           if [ -d "${p}/lib/caja/extensions-2.0" ]; then
-            ${addToXDGDirs p}
+              ${addToXDGDirs p}
           fi
-          '')
-          config.environment.systemPackages
-        }
+          '') config.environment.systemPackages}
 
-        # Let mate-panel find applets
-        export MATE_PANEL_APPLETS_DIR=$MATE_PANEL_APPLETS_DIR''${MATE_PANEL_APPLETS_DIR:+:}${config.system.path}/share/mate-panel/applets
-        export MATE_PANEL_EXTRA_MODULES=$MATE_PANEL_EXTRA_MODULES''${MATE_PANEL_EXTRA_MODULES:+:}${config.system.path}/lib/mate-panel/applets
+          # Add mate-control-center paths to some XDG variables because its schemas are needed by mate-settings-daemon, and mate-settings-daemon is a dependency for mate-control-center (that is, they are mutually recursive)
+          ${addToXDGDirs pkgs.mate.mate-control-center}
+      fi
+    '';
 
-        # Add mate-control-center paths to some XDG variables because its schemas are needed by mate-settings-daemon, and mate-settings-daemon is a dependency for mate-control-center (that is, they are mutually recursive)
-        ${addToXDGDirs pkgs.mate.mate-control-center}
+    # Let mate-panel find applets
+    environment.sessionVariables."MATE_PANEL_APPLETS_DIR" = "${config.system.path}/share/mate-panel/applets";
+    environment.sessionVariables."MATE_PANEL_EXTRA_MODULES" = "${config.system.path}/lib/mate-panel/applets";
 
-        ${pkgs.mate.mate-session-manager}/bin/mate-session ${optionalString cfg.debug "--debug"} &
-        waitPID=$!
-      '';
-    };
+    # Debugging
+    environment.sessionVariables.MATE_SESSION_DEBUG = mkIf cfg.debug "1";
 
     environment.systemPackages =
       pkgs.mate.basePackages ++
diff --git a/nixos/modules/services/x11/desktop-managers/pantheon.nix b/nixos/modules/services/x11/desktop-managers/pantheon.nix
index b46a2d189ef..869c6694489 100644
--- a/nixos/modules/services/x11/desktop-managers/pantheon.nix
+++ b/nixos/modules/services/x11/desktop-managers/pantheon.nix
@@ -16,7 +16,10 @@ in
 
 {
 
-  meta.maintainers = pkgs.pantheon.maintainers;
+  meta = {
+    doc = ./pantheon.xml;
+    maintainers = pkgs.pantheon.maintainers;
+  };
 
   options = {
 
diff --git a/nixos/modules/services/x11/desktop-managers/pantheon.xml b/nixos/modules/services/x11/desktop-managers/pantheon.xml
new file mode 100644
index 00000000000..4d92a7446c0
--- /dev/null
+++ b/nixos/modules/services/x11/desktop-managers/pantheon.xml
@@ -0,0 +1,130 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="chap-pantheon">
+ <title>Pantheon Destkop</title>
+ <para>
+  Pantheon is the desktop environment created for the elementary OS distribution. It is written from scratch in Vala, utilizing GNOME technologies with GTK 3 and Granite.
+ </para>
+ <section xml:id="sec-pantheon-enable">
+  <title>Enabling Pantheon</title>
+
+  <para>
+   All of Pantheon is working in NixOS and the applications should be available, aside from a few <link xlink:href="https://github.com/NixOS/nixpkgs/issues/58161">exceptions</link>. To enable Pantheon, set
+<programlisting>
+<xref linkend="opt-services.xserver.desktopManager.pantheon.enable"/> = true;
+</programlisting>
+   This automatically enables LightDM and Pantheon's LightDM greeter. If you'd like to disable this, set
+<programlisting>
+<xref linkend="opt-services.xserver.displayManager.lightdm.greeters.pantheon.enable"/> = false;
+<xref linkend="opt-services.xserver.displayManager.lightdm.enable"/> = false;
+</programlisting>
+   but please be aware using Pantheon without LightDM as a display manager will break screenlocking from the UI. The NixOS module for Pantheon installs all of Pantheon's default applications. If you'd like to not install Pantheon's apps, set
+<programlisting>
+<xref linkend="opt-services.pantheon.apps.enable"/> = false;
+</programlisting>
+   You can also use <xref linkend="opt-environment.pantheon.excludePackages"/> to remove any other app (like <package>geary</package>).
+  </para>
+ </section>
+ <section xml:id="sec-pantheon-wingpanel-switchboard">
+  <title>Wingpanel and Switchboard plugins</title>
+
+  <para>
+   Wingpanel and Switchboard work differently than they do in other distributions, as far as using plugins. You cannot install a plugin globally (like with <option>environment.systemPackages</option>) to start using it. You should instead be using the following options:
+   <itemizedlist>
+    <listitem>
+     <para>
+      <xref linkend="opt-services.xserver.desktopManager.pantheon.extraWingpanelIndicators"/>
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      <xref linkend="opt-services.xserver.desktopManager.pantheon.extraSwitchboardPlugs"/>
+     </para>
+    </listitem>
+   </itemizedlist>
+   to configure the programs with plugs or indicators.
+  </para>
+
+  <para>
+   The difference in NixOS is both these programs are patched to load plugins from a directory that is the value of an environment variable. All of which is controlled in Nix. If you need to configure the particular packages manually you can override the packages like:
+<programlisting>
+wingpanel-with-indicators.override {
+  indicators = [
+    pkgs.some-special-indicator
+  ];
+};
+
+switchboard-with-plugs.override {
+  plugs = [
+    pkgs.some-special-plug
+  ];
+};
+</programlisting>
+   please note that, like how the NixOS options describe these as extra plugins, this would only add to the default plugins included with the programs. If for some reason you'd like to configure which plugins to use exactly, both packages have an argument for this:
+<programlisting>
+wingpanel-with-indicators.override {
+  useDefaultIndicators = false;
+  indicators = specialListOfIndicators;
+};
+
+switchboard-with-plugs.override {
+  useDefaultPlugs = false;
+  plugs = specialListOfPlugs;
+};
+</programlisting>
+   this could be most useful for testing a particular plug-in in isolation.
+  </para>
+ </section>
+ <section xml:id="sec-pantheon-faq">
+  <title>FAQ</title>
+
+  <variablelist>
+   <varlistentry xml:id="sec-pantheon-faq-messed-up-theme">
+    <term>
+     I have switched from a different desktop and Pantheon’s theming looks messed up.
+    </term>
+    <listitem>
+     <para>
+      Open Switchboard and go to: <guilabel>Administration</guilabel> → <guilabel>About</guilabel> → <guilabel>Restore Default Settings</guilabel> → <guibutton>Restore Settings</guibutton>. This will reset any dconf settings to their Pantheon defaults. Note this could reset certain GNOME specific preferences if that desktop was used prior.
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry xml:id="sec-pantheon-faq-slow-shutdown">
+    <term>
+     Using Pantheon sometimes makes my shutdown take a long time.
+    </term>
+    <listitem>
+     <para>
+      We have not yet determined what processes fight with systemd during shutdown, there are many reports. In elementary OS the default system timeout is lowered to lessen the impact of the issue. If you'd like to do this in NixOS, set
+<programlisting>
+ <xref linkend="opt-systemd.extraConfig"/> = ''
+  DefaultTimeoutStopSec=10s
+  DefaultTimeoutStartSec=10s
+'';
+</programlisting>
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry xml:id="sec-pantheon-faq-gnome3-and-pantheon">
+    <term>
+     I cannot enable both GNOME 3 and Pantheon.
+    </term>
+    <listitem>
+     <para>
+      This is a known <link xlink:href="https://github.com/NixOS/nixpkgs/issues/64611">issue</link> and there is no known workaround.
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry xml:id="sec-pantheon-faq-appcenter">
+    <term>
+     Does AppCenter work, or is it available?
+    </term>
+    <listitem>
+     <para>
+      AppCenter has been available since 20.03, but it is of little use. This is because there is no functioning PackageKit backend for Nix 2.0. In the near future you will be able to install Flatpak applications from AppCenter on NixOS. See this <link xlink:href="https://github.com/NixOS/nixpkgs/issues/70214">issue</link>.
+     </para>
+    </listitem>
+   </varlistentry>
+  </variablelist>
+ </section>
+</chapter>
diff --git a/nixos/modules/services/x11/desktop-managers/plasma5.nix b/nixos/modules/services/x11/desktop-managers/plasma5.nix
index f3bf9268b29..60ef0159ff1 100644
--- a/nixos/modules/services/x11/desktop-managers/plasma5.nix
+++ b/nixos/modules/services/x11/desktop-managers/plasma5.nix
@@ -52,6 +52,8 @@ let
   '';
 
   activationScript = ''
+    ${set_XDG_CONFIG_HOME}
+
     # The KDE icon cache is supposed to update itself automatically, but it uses
     # the timestamp on the icon theme directory as a trigger. This doesn't work
     # on NixOS because the timestamp never changes. As a workaround, delete the
@@ -62,7 +64,7 @@ let
     # xdg-desktop-settings generates this empty file but
     # it makes kbuildsyscoca5 fail silently. To fix this
     # remove that menu if it exists.
-    rm -fv ''${XDG_CONFIG_HOME:?}/menus/applications-merged/xdg-desktop-menu-dummy.menu
+    rm -fv ''${XDG_CONFIG_HOME}/menus/applications-merged/xdg-desktop-menu-dummy.menu
 
     # Qt writes a weird ‘libraryPath’ line to
     # ~/.config/Trolltech.conf that causes the KDE plugin
@@ -71,7 +73,7 @@ let
     # disastrous, so here we nuke references to the Nix store
     # in Trolltech.conf.  A better solution would be to stop
     # Qt from doing this wackiness in the first place.
-    trolltech_conf="''${XDG_CONFIG_HOME:?}/Trolltech.conf"
+    trolltech_conf="''${XDG_CONFIG_HOME}/Trolltech.conf"
     if [ -e "$trolltech_conf" ]; then
         ${sed} -i "$trolltech_conf" -e '/nix\\store\|nix\/store/ d'
     fi
@@ -84,10 +86,20 @@ let
     ${pkgs.libsForQt5.kservice}/bin/kbuildsycoca5
   '';
 
+  set_XDG_CONFIG_HOME = ''
+      # Set the default XDG_CONFIG_HOME if it is unset.
+      # Per the XDG Base Directory Specification:
+      # https://specifications.freedesktop.org/basedir-spec/latest
+      # 1. Never export this variable! If it is unset, then child processes are
+      # expected to set the default themselves.
+      # 2. Contaminate / if $HOME is unset; do not check if $HOME is set.
+      XDG_CONFIG_HOME=''${XDG_CONFIG_HOME:-$HOME/.config}
+  '';
+
   startplasma =
     ''
-      export XDG_CONFIG_HOME="''${XDG_CONFIG_HOME:-$HOME/.config}"
-      mkdir -p "''${XDG_CONFIG_HOME:?}"
+      ${set_XDG_CONFIG_HOME}
+      mkdir -p "''${XDG_CONFIG_HOME}"
 
     ''
     + optionalString pulseaudio.enable ''
@@ -100,10 +112,10 @@ let
       ${activationScript}
 
       # Create default configurations if Plasma has never been started.
-      kdeglobals="''${XDG_CONFIG_HOME:?}/kdeglobals"
+      kdeglobals="''${XDG_CONFIG_HOME}/kdeglobals"
       if ! [ -f "$kdeglobals" ]
       then
-          kcminputrc="''${XDG_CONFIG_HOME:?}/kcminputrc"
+          kcminputrc="''${XDG_CONFIG_HOME}/kcminputrc"
           if ! [ -f "$kcminputrc" ]
           then
               cat ${kcminputrc} >"$kcminputrc"
@@ -115,7 +127,7 @@ let
               cat ${gtkrc2} >"$gtkrc2"
           fi
 
-          gtk3_settings="''${XDG_CONFIG_HOME:?}/gtk-3.0/settings.ini"
+          gtk3_settings="''${XDG_CONFIG_HOME}/gtk-3.0/settings.ini"
           if ! [ -f "$gtk3_settings" ]
           then
               mkdir -p "$(dirname "$gtk3_settings")"
diff --git a/nixos/modules/services/x11/display-managers/gdm.nix b/nixos/modules/services/x11/display-managers/gdm.nix
index 325023f4121..e0ac47bb766 100644
--- a/nixos/modules/services/x11/display-managers/gdm.nix
+++ b/nixos/modules/services/x11/display-managers/gdm.nix
@@ -166,9 +166,10 @@ in
       };
 
     systemd.tmpfiles.rules = [
-      "d /run/gdm/.config 0711 gdm gdm -"
+      "d /run/gdm/.config 0711 gdm gdm"
     ] ++ optionals config.hardware.pulseaudio.enable [
-      "L+ /run/gdm/.config/pulse - - - - ${pulseConfig}"
+      "d /run/gdm/.config/pulse 0711 gdm gdm"
+      "L+ /run/gdm/.config/pulse/${pulseConfig.name} - - - - ${pulseConfig}"
     ] ++ optionals config.services.gnome3.gnome-initial-setup.enable [
       # Create stamp file for gnome-initial-setup to prevent it starting in GDM.
       "f /run/gdm/.config/gnome-initial-setup-done 0711 gdm gdm - yes"
diff --git a/nixos/modules/services/x11/display-managers/lightdm-greeters/tiny.nix b/nixos/modules/services/x11/display-managers/lightdm-greeters/tiny.nix
new file mode 100644
index 00000000000..a9ba8e6280d
--- /dev/null
+++ b/nixos/modules/services/x11/display-managers/lightdm-greeters/tiny.nix
@@ -0,0 +1,92 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  dmcfg = config.services.xserver.displayManager;
+  ldmcfg = dmcfg.lightdm;
+  cfg = ldmcfg.greeters.tiny;
+
+in
+{
+  options = {
+
+    services.xserver.displayManager.lightdm.greeters.tiny = {
+
+      enable = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Whether to enable lightdm-tiny-greeter as the lightdm greeter.
+
+          Note that this greeter starts only the default X session.
+          You can configure the default X session using
+          <xref linkend="opt-services.xserver.displayManager.defaultSession"/>.
+        '';
+      };
+
+      label = {
+        user = mkOption {
+          type = types.str;
+          default = "Username";
+          description = ''
+            The string to represent the user_text label.
+          '';
+        };
+
+        pass = mkOption {
+          type = types.str;
+          default = "Password";
+          description = ''
+            The string to represent the pass_text label.
+          '';
+        };
+      };
+
+
+      extraConfig = mkOption {
+        type = types.lines;
+        default = "";
+        description = ''
+          Section to describe style and ui.
+        '';
+      };
+
+    };
+
+  };
+
+  config = mkIf (ldmcfg.enable && cfg.enable) {
+
+    services.xserver.displayManager.lightdm.greeters.gtk.enable = false;
+
+    nixpkgs.config.lightdm-tiny-greeter.conf =
+    let
+      configHeader = ''
+        #include <gtk/gtk.h>
+        static const char *user_text = "${cfg.label.user}";
+        static const char *pass_text = "${cfg.label.pass}";
+        static const char *session = "${dmcfg.defaultSession}";
+      '';
+    in
+      optionalString (cfg.extraConfig != "")
+        (configHeader + cfg.extraConfig);
+
+    services.xserver.displayManager.lightdm.greeter =
+      mkDefault {
+        package = pkgs.lightdm-tiny-greeter.xgreeters;
+        name = "lightdm-tiny-greeter";
+      };
+
+    assertions = [
+      {
+        assertion = dmcfg.defaultSession != null;
+        message = ''
+          Please set: services.xserver.displayManager.defaultSession
+        '';
+      }
+    ];
+
+  };
+}
diff --git a/nixos/modules/services/x11/display-managers/lightdm.nix b/nixos/modules/services/x11/display-managers/lightdm.nix
index f7face0adb7..cb7b5f95958 100644
--- a/nixos/modules/services/x11/display-managers/lightdm.nix
+++ b/nixos/modules/services/x11/display-managers/lightdm.nix
@@ -77,6 +77,7 @@ in
     ./lightdm-greeters/mini.nix
     ./lightdm-greeters/enso-os.nix
     ./lightdm-greeters/pantheon.nix
+    ./lightdm-greeters/tiny.nix
   ];
 
   options = {
diff --git a/nixos/modules/services/x11/xserver.nix b/nixos/modules/services/x11/xserver.nix
index 7f0de96d208..74d702ea1c3 100644
--- a/nixos/modules/services/x11/xserver.nix
+++ b/nixos/modules/services/x11/xserver.nix
@@ -573,7 +573,7 @@ in
            then { modules = [xorg.${"xf86video" + name}]; }
            else null)
           knownVideoDrivers;
-      in optional (driver != null) ({ inherit name; modules = []; driverName = name; } // driver));
+      in optional (driver != null) ({ inherit name; modules = []; driverName = name; display = true; } // driver));
 
     assertions = [
       { assertion = config.security.polkit.enable;
@@ -740,7 +740,7 @@ in
           ${cfg.serverLayoutSection}
           # Reference the Screen sections for each driver.  This will
           # cause the X server to try each in turn.
-          ${flip concatMapStrings cfg.drivers (d: ''
+          ${flip concatMapStrings (filter (d: d.display) cfg.drivers) (d: ''
             Screen "Screen-${d.name}[0]"
           '')}
         EndSection
@@ -764,42 +764,44 @@ in
             ${driver.deviceSection or ""}
             ${xrandrDeviceSection}
           EndSection
+          ${optionalString driver.display ''
+
+            Section "Screen"
+              Identifier "Screen-${driver.name}[0]"
+              Device "Device-${driver.name}[0]"
+              ${optionalString (cfg.monitorSection != "") ''
+                Monitor "Monitor[0]"
+              ''}
+
+              ${cfg.screenSection}
+              ${driver.screenSection or ""}
+
+              ${optionalString (cfg.defaultDepth != 0) ''
+                DefaultDepth ${toString cfg.defaultDepth}
+              ''}
+
+              ${optionalString
+                  (driver.name != "virtualbox" &&
+                  (cfg.resolutions != [] ||
+                    cfg.extraDisplaySettings != "" ||
+                    cfg.virtualScreen != null))
+                (let
+                  f = depth:
+                    ''
+                      SubSection "Display"
+                        Depth ${toString depth}
+                        ${optionalString (cfg.resolutions != [])
+                          "Modes ${concatMapStrings (res: ''"${toString res.x}x${toString res.y}"'') cfg.resolutions}"}
+                        ${cfg.extraDisplaySettings}
+                        ${optionalString (cfg.virtualScreen != null)
+                          "Virtual ${toString cfg.virtualScreen.x} ${toString cfg.virtualScreen.y}"}
+                      EndSubSection
+                    '';
+                in concatMapStrings f [8 16 24]
+              )}
 
-          Section "Screen"
-            Identifier "Screen-${driver.name}[0]"
-            Device "Device-${driver.name}[0]"
-            ${optionalString (cfg.monitorSection != "") ''
-              Monitor "Monitor[0]"
-            ''}
-
-            ${cfg.screenSection}
-            ${driver.screenSection or ""}
-
-            ${optionalString (cfg.defaultDepth != 0) ''
-              DefaultDepth ${toString cfg.defaultDepth}
-            ''}
-
-            ${optionalString
-                (driver.name != "virtualbox" &&
-                 (cfg.resolutions != [] ||
-                  cfg.extraDisplaySettings != "" ||
-                  cfg.virtualScreen != null))
-              (let
-                f = depth:
-                  ''
-                    SubSection "Display"
-                      Depth ${toString depth}
-                      ${optionalString (cfg.resolutions != [])
-                        "Modes ${concatMapStrings (res: ''"${toString res.x}x${toString res.y}"'') cfg.resolutions}"}
-                      ${cfg.extraDisplaySettings}
-                      ${optionalString (cfg.virtualScreen != null)
-                        "Virtual ${toString cfg.virtualScreen.x} ${toString cfg.virtualScreen.y}"}
-                    EndSubSection
-                  '';
-              in concatMapStrings f [8 16 24]
-            )}
-
-          EndSection
+            EndSection
+          ''}
         '')}
 
         ${xrandrMonitorSections}