kea: use separate runtime directories for each service

Kea may clean the runtime directory when starting (or maybe systemd does
it). I ran into this issue when restarting Kea after changing its
configuration, so I think the fact it normally doesn't clean it is a
race condition (it's cleaned on service start, and normally all Kea
services start at roughly the same time).

4 files changed, 18 insertions, 13 deletions

diff --git a/nixos/doc/manual/release-notes/rl-2311.section.md b/nixos/doc/manual/release-notes/rl-2311.section.md
index a3170860b13..bd0d74a8885 100644
--- a/nixos/doc/manual/release-notes/rl-2311.section.md
+++ b/nixos/doc/manual/release-notes/rl-2311.section.md
@@ -333,6 +333,8 @@
 
 - `ssm-agent` package and module were renamed to `amazon-ssm-agent` to be consistent with the upstream package name.
 
+- `services.kea.{ctrl-agent,dhcp-ddns,dhcp,dhcp6}` now use separate runtime directories instead of `/run/kea` to work around the runtime directory being cleared on service start.
+
 ## Other Notable Changes {#sec-release-23.11-notable-changes}
 
 - The Cinnamon module now enables XDG desktop integration by default. If you are experiencing collisions related to xdg-desktop-portal-gtk you can safely remove `xdg.portal.extraPortals = [ pkgs.xdg-desktop-portal-gtk ];` from your NixOS configuration.
diff --git a/nixos/modules/services/monitoring/prometheus/exporters/kea.nix b/nixos/modules/services/monitoring/prometheus/exporters/kea.nix
index ed33c72f644..8b1cd47d0a4 100644
--- a/nixos/modules/services/monitoring/prometheus/exporters/kea.nix
+++ b/nixos/modules/services/monitoring/prometheus/exporters/kea.nix
@@ -15,8 +15,8 @@ in {
       type = types.listOf types.str;
       example = literalExpression ''
         [
-          "/run/kea/kea-dhcp4.socket"
-          "/run/kea/kea-dhcp6.socket"
+          "/run/kea-dhcp4/kea-dhcp4.socket"
+          "/run/kea-dhcp6/kea-dhcp6.socket"
         ]
       '';
       description = lib.mdDoc ''
diff --git a/nixos/modules/services/networking/kea.nix b/nixos/modules/services/networking/kea.nix
index 945f4113bd4..2f922a026a3 100644
--- a/nixos/modules/services/networking/kea.nix
+++ b/nixos/modules/services/networking/kea.nix
@@ -254,7 +254,6 @@ in
       DynamicUser = true;
       User = "kea";
       ConfigurationDirectory = "kea";
-      RuntimeDirectory = "kea";
       StateDirectory = "kea";
       UMask = "0077";
     };
@@ -289,8 +288,8 @@ in
       ];
 
       environment = {
-        KEA_PIDFILE_DIR = "/run/kea";
-        KEA_LOCKFILE_DIR = "/run/kea";
+        KEA_PIDFILE_DIR = "/run/kea-ctrl-agent";
+        KEA_LOCKFILE_DIR = "/run/kea-ctrl-agent";
       };
 
       restartTriggers = [
@@ -301,6 +300,7 @@ in
         ExecStart = "${package}/bin/kea-ctrl-agent -c /etc/kea/ctrl-agent.conf ${lib.escapeShellArgs cfg.ctrl-agent.extraArgs}";
         KillMode = "process";
         Restart = "on-failure";
+        RuntimeDirectory = "kea-ctrl-agent";
       } // commonServiceConfig;
     };
   })
@@ -329,8 +329,8 @@ in
       ];
 
       environment = {
-        KEA_PIDFILE_DIR = "/run/kea";
-        KEA_LOCKFILE_DIR = "/run/kea";
+        KEA_PIDFILE_DIR = "/run/kea-dhcp4";
+        KEA_LOCKFILE_DIR = "/run/kea-dhcp4";
       };
 
       restartTriggers = [
@@ -348,6 +348,7 @@ in
           "CAP_NET_BIND_SERVICE"
           "CAP_NET_RAW"
         ];
+        RuntimeDirectory = "kea-dhcp4";
       } // commonServiceConfig;
     };
   })
@@ -376,8 +377,8 @@ in
       ];
 
       environment = {
-        KEA_PIDFILE_DIR = "/run/kea";
-        KEA_LOCKFILE_DIR = "/run/kea";
+        KEA_PIDFILE_DIR = "/run/kea-dhcp6";
+        KEA_LOCKFILE_DIR = "/run/kea-dhcp6";
       };
 
       restartTriggers = [
@@ -393,6 +394,7 @@ in
         CapabilityBoundingSet = [
           "CAP_NET_BIND_SERVICE"
         ];
+        RuntimeDirectory = "kea-dhcp6";
       } // commonServiceConfig;
     };
   })
@@ -421,8 +423,8 @@ in
       ];
 
       environment = {
-        KEA_PIDFILE_DIR = "/run/kea";
-        KEA_LOCKFILE_DIR = "/run/kea";
+        KEA_PIDFILE_DIR = "/run/kea-dhcp-ddns";
+        KEA_LOCKFILE_DIR = "/run/kea-dhcp-ddns";
       };
 
       restartTriggers = [
@@ -437,6 +439,7 @@ in
         CapabilityBoundingSet = [
           "CAP_NET_BIND_SERVICE"
         ];
+        RuntimeDirectory = "kea-dhcp-ddns";
       } // commonServiceConfig;
     };
   })
diff --git a/nixos/tests/prometheus-exporters.nix b/nixos/tests/prometheus-exporters.nix
index d42a9e30399..7fd82496720 100644
--- a/nixos/tests/prometheus-exporters.nix
+++ b/nixos/tests/prometheus-exporters.nix
@@ -416,8 +416,8 @@ let
     };
 
     kea = let
-      controlSocketPathV4 = "/run/kea/dhcp4.sock";
-      controlSocketPathV6 = "/run/kea/dhcp6.sock";
+      controlSocketPathV4 = "/run/kea-dhcp4/dhcp4.sock";
+      controlSocketPathV6 = "/run/kea-dhcp6/dhcp6.sock";
     in
     {
       exporterConfig = {