nixos: nixos/doc/manual/installation/upgrading.xml to CommonMark

4 files changed, 271 insertions, 140 deletions

diff --git a/nixos/doc/manual/from_md/installation/upgrading.chapter.xml b/nixos/doc/manual/from_md/installation/upgrading.chapter.xml
new file mode 100644
index 00000000000..c0c5a2190fb
--- /dev/null
+++ b/nixos/doc/manual/from_md/installation/upgrading.chapter.xml
@@ -0,0 +1,152 @@
+<chapter xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="sec-upgrading">
+  <title>Upgrading NixOS</title>
+  <para>
+    The best way to keep your NixOS installation up to date is to use
+    one of the NixOS <emphasis>channels</emphasis>. A channel is a Nix
+    mechanism for distributing Nix expressions and associated binaries.
+    The NixOS channels are updated automatically from NixOS’s Git
+    repository after certain tests have passed and all packages have
+    been built. These channels are:
+  </para>
+  <itemizedlist>
+    <listitem>
+      <para>
+        <emphasis>Stable channels</emphasis>, such as
+        <link xlink:href="https://nixos.org/channels/nixos-21.05"><literal>nixos-21.05</literal></link>.
+        These only get conservative bug fixes and package upgrades. For
+        instance, a channel update may cause the Linux kernel on your
+        system to be upgraded from 4.19.34 to 4.19.38 (a minor bug fix),
+        but not from 4.19.x to 4.20.x (a major change that has the
+        potential to break things). Stable channels are generally
+        maintained until the next stable branch is created.
+      </para>
+    </listitem>
+    <listitem>
+      <para>
+        The <emphasis>unstable channel</emphasis>,
+        <link xlink:href="https://nixos.org/channels/nixos-unstable"><literal>nixos-unstable</literal></link>.
+        This corresponds to NixOS’s main development branch, and may
+        thus see radical changes between channel updates. It’s not
+        recommended for production systems.
+      </para>
+    </listitem>
+    <listitem>
+      <para>
+        <emphasis>Small channels</emphasis>, such as
+        <link xlink:href="https://nixos.org/channels/nixos-21.05-small"><literal>nixos-21.05-small</literal></link>
+        or
+        <link xlink:href="https://nixos.org/channels/nixos-unstable-small"><literal>nixos-unstable-small</literal></link>.
+        These are identical to the stable and unstable channels
+        described above, except that they contain fewer binary packages.
+        This means they get updated faster than the regular channels
+        (for instance, when a critical security patch is committed to
+        NixOS’s source tree), but may require more packages to be built
+        from source than usual. They’re mostly intended for server
+        environments and as such contain few GUI applications.
+      </para>
+    </listitem>
+  </itemizedlist>
+  <para>
+    To see what channels are available, go to
+    <link xlink:href="https://nixos.org/channels">https://nixos.org/channels</link>.
+    (Note that the URIs of the various channels redirect to a directory
+    that contains the channel’s latest version and includes ISO images
+    and VirtualBox appliances.) Please note that during the release
+    process, channels that are not yet released will be present here as
+    well. See the Getting NixOS page
+    <link xlink:href="https://nixos.org/nixos/download.html">https://nixos.org/nixos/download.html</link>
+    to find the newest supported stable release.
+  </para>
+  <para>
+    When you first install NixOS, you’re automatically subscribed to the
+    NixOS channel that corresponds to your installation source. For
+    instance, if you installed from a 21.05 ISO, you will be subscribed
+    to the <literal>nixos-21.05</literal> channel. To see which NixOS
+    channel you’re subscribed to, run the following as root:
+  </para>
+  <programlisting>
+# nix-channel --list | grep nixos
+nixos https://nixos.org/channels/nixos-unstable
+</programlisting>
+  <para>
+    To switch to a different NixOS channel, do
+  </para>
+  <programlisting>
+# nix-channel --add https://nixos.org/channels/channel-name nixos
+</programlisting>
+  <para>
+    (Be sure to include the <literal>nixos</literal> parameter at the
+    end.) For instance, to use the NixOS 21.05 stable channel:
+  </para>
+  <programlisting>
+# nix-channel --add https://nixos.org/channels/nixos-21.05 nixos
+</programlisting>
+  <para>
+    If you have a server, you may want to use the <quote>small</quote>
+    channel instead:
+  </para>
+  <programlisting>
+# nix-channel --add https://nixos.org/channels/nixos-21.05-small nixos
+</programlisting>
+  <para>
+    And if you want to live on the bleeding edge:
+  </para>
+  <programlisting>
+# nix-channel --add https://nixos.org/channels/nixos-unstable nixos
+</programlisting>
+  <para>
+    You can then upgrade NixOS to the latest version in your chosen
+    channel by running
+  </para>
+  <programlisting>
+# nixos-rebuild switch --upgrade
+</programlisting>
+  <para>
+    which is equivalent to the more verbose
+    <literal>nix-channel --update nixos; nixos-rebuild switch</literal>.
+  </para>
+  <note>
+    <para>
+      Channels are set per user. This means that running
+      <literal>nix-channel --add</literal> as a non root user (or
+      without sudo) will not affect configuration in
+      <literal>/etc/nixos/configuration.nix</literal>
+    </para>
+  </note>
+  <warning>
+    <para>
+      It is generally safe to switch back and forth between channels.
+      The only exception is that a newer NixOS may also have a newer Nix
+      version, which may involve an upgrade of Nix’s database schema.
+      This cannot be undone easily, so in that case you will not be able
+      to go back to your original channel.
+    </para>
+  </warning>
+  <section xml:id="sec-upgrading-automatic">
+    <title>Automatic Upgrades</title>
+    <para>
+      You can keep a NixOS system up-to-date automatically by adding the
+      following to <literal>configuration.nix</literal>:
+    </para>
+    <programlisting language="bash">
+system.autoUpgrade.enable = true;
+system.autoUpgrade.allowReboot = true;
+</programlisting>
+    <para>
+      This enables a periodically executed systemd service named
+      <literal>nixos-upgrade.service</literal>. If the
+      <literal>allowReboot</literal> option is <literal>false</literal>,
+      it runs <literal>nixos-rebuild switch --upgrade</literal> to
+      upgrade NixOS to the latest version in the current channel. (To
+      see when the service runs, see
+      <literal>systemctl list-timers</literal>.) If
+      <literal>allowReboot</literal> is <literal>true</literal>, then
+      the system will automatically reboot if the new generation
+      contains a different kernel, initrd or kernel modules. You can
+      also specify a channel explicitly, e.g.
+    </para>
+    <programlisting language="bash">
+system.autoUpgrade.channel = https://nixos.org/channels/nixos-21.05;
+</programlisting>
+  </section>
+</chapter>
diff --git a/nixos/doc/manual/installation/installation.xml b/nixos/doc/manual/installation/installation.xml
index 65564e8b1e3..cc18a9c6e9f 100644
--- a/nixos/doc/manual/installation/installation.xml
+++ b/nixos/doc/manual/installation/installation.xml
@@ -13,5 +13,5 @@
  <xi:include href="../from_md/installation/obtaining.chapter.xml" />
  <xi:include href="installing.xml" />
  <xi:include href="../from_md/installation/changing-config.chapter.xml" />
- <xi:include href="upgrading.xml" />
+ <xi:include href="../from_md/installation/upgrading.chapter.xml" />
 </part>
diff --git a/nixos/doc/manual/installation/upgrading.chapter.md b/nixos/doc/manual/installation/upgrading.chapter.md
new file mode 100644
index 00000000000..b7903b9d3cb
--- /dev/null
+++ b/nixos/doc/manual/installation/upgrading.chapter.md
@@ -0,0 +1,118 @@
+# Upgrading NixOS {#sec-upgrading}
+
+The best way to keep your NixOS installation up to date is to use one of
+the NixOS *channels*. A channel is a Nix mechanism for distributing Nix
+expressions and associated binaries. The NixOS channels are updated
+automatically from NixOS's Git repository after certain tests have
+passed and all packages have been built. These channels are:
+
+-   *Stable channels*, such as [`nixos-21.05`](https://nixos.org/channels/nixos-21.05).
+    These only get conservative bug fixes and package upgrades. For
+    instance, a channel update may cause the Linux kernel on your system
+    to be upgraded from 4.19.34 to 4.19.38 (a minor bug fix), but not
+    from 4.19.x to 4.20.x (a major change that has the potential to break things).
+    Stable channels are generally maintained until the next stable
+    branch is created.
+
+-   The *unstable channel*, [`nixos-unstable`](https://nixos.org/channels/nixos-unstable).
+    This corresponds to NixOS's main development branch, and may thus see
+    radical changes between channel updates. It's not recommended for
+    production systems.
+
+-   *Small channels*, such as [`nixos-21.05-small`](https://nixos.org/channels/nixos-21.05-small)
+    or [`nixos-unstable-small`](https://nixos.org/channels/nixos-unstable-small).
+    These are identical to the stable and unstable channels described above,
+    except that they contain fewer binary packages. This means they get updated
+    faster than the regular channels (for instance, when a critical security patch
+    is committed to NixOS's source tree), but may require more packages to be
+    built from source than usual. They're mostly intended for server environments
+    and as such contain few GUI applications.
+
+To see what channels are available, go to <https://nixos.org/channels>.
+(Note that the URIs of the various channels redirect to a directory that
+contains the channel's latest version and includes ISO images and
+VirtualBox appliances.) Please note that during the release process,
+channels that are not yet released will be present here as well. See the
+Getting NixOS page <https://nixos.org/nixos/download.html> to find the
+newest supported stable release.
+
+When you first install NixOS, you're automatically subscribed to the
+NixOS channel that corresponds to your installation source. For
+instance, if you installed from a 21.05 ISO, you will be subscribed to
+the `nixos-21.05` channel. To see which NixOS channel you're subscribed
+to, run the following as root:
+
+```ShellSession
+# nix-channel --list | grep nixos
+nixos https://nixos.org/channels/nixos-unstable
+```
+
+To switch to a different NixOS channel, do
+
+```ShellSession
+# nix-channel --add https://nixos.org/channels/channel-name nixos
+```
+
+(Be sure to include the `nixos` parameter at the end.) For instance, to
+use the NixOS 21.05 stable channel:
+
+```ShellSession
+# nix-channel --add https://nixos.org/channels/nixos-21.05 nixos
+```
+
+If you have a server, you may want to use the "small" channel instead:
+
+```ShellSession
+# nix-channel --add https://nixos.org/channels/nixos-21.05-small nixos
+```
+
+And if you want to live on the bleeding edge:
+
+```ShellSession
+# nix-channel --add https://nixos.org/channels/nixos-unstable nixos
+```
+
+You can then upgrade NixOS to the latest version in your chosen channel
+by running
+
+```ShellSession
+# nixos-rebuild switch --upgrade
+```
+
+which is equivalent to the more verbose `nix-channel --update nixos; nixos-rebuild switch`.
+
+::: {.note}
+Channels are set per user. This means that running `nix-channel --add`
+as a non root user (or without sudo) will not affect
+configuration in `/etc/nixos/configuration.nix`
+:::
+
+::: {.warning}
+It is generally safe to switch back and forth between channels. The only
+exception is that a newer NixOS may also have a newer Nix version, which
+may involve an upgrade of Nix's database schema. This cannot be undone
+easily, so in that case you will not be able to go back to your original
+channel.
+:::
+
+## Automatic Upgrades {#sec-upgrading-automatic}
+
+You can keep a NixOS system up-to-date automatically by adding the
+following to `configuration.nix`:
+
+```nix
+system.autoUpgrade.enable = true;
+system.autoUpgrade.allowReboot = true;
+```
+
+This enables a periodically executed systemd service named
+`nixos-upgrade.service`. If the `allowReboot` option is `false`, it runs
+`nixos-rebuild switch --upgrade` to upgrade NixOS to the latest version
+in the current channel. (To see when the service runs, see `systemctl list-timers`.)
+If `allowReboot` is `true`, then the system will automatically reboot if
+the new generation contains a different kernel, initrd or kernel
+modules. You can also specify a channel explicitly, e.g.
+
+```nix
+system.autoUpgrade.channel = https://nixos.org/channels/nixos-21.05;
+```
diff --git a/nixos/doc/manual/installation/upgrading.xml b/nixos/doc/manual/installation/upgrading.xml
deleted file mode 100644
index 960d4fa9a43..00000000000
--- a/nixos/doc/manual/installation/upgrading.xml
+++ /dev/null
@@ -1,139 +0,0 @@
-<chapter xmlns="http://docbook.org/ns/docbook"
-         xmlns:xlink="http://www.w3.org/1999/xlink"
-         version="5.0"
-         xml:id="sec-upgrading">
- <title>Upgrading NixOS</title>
- <para>
-  The best way to keep your NixOS installation up to date is to use one of the
-  NixOS <emphasis>channels</emphasis>. A channel is a Nix mechanism for
-  distributing Nix expressions and associated binaries. The NixOS channels are
-  updated automatically from NixOS’s Git repository after certain tests have
-  passed and all packages have been built. These channels are:
-  <itemizedlist>
-   <listitem>
-    <para>
-     <emphasis>Stable channels</emphasis>, such as
-     <literal
-    xlink:href="https://nixos.org/channels/nixos-21.05">nixos-21.05</literal>.
-     These only get conservative bug fixes and package upgrades. For instance,
-     a channel update may cause the Linux kernel on your system to be upgraded
-     from 4.19.34 to 4.19.38 (a minor bug fix), but not from
-     4.19.<replaceable>x</replaceable> to 4.20.<replaceable>x</replaceable> (a
-     major change that has the potential to break things). Stable channels are
-     generally maintained until the next stable branch is created.
-    </para>
-    <para></para>
-   </listitem>
-   <listitem>
-    <para>
-     The <emphasis>unstable channel</emphasis>,
-     <literal
-    xlink:href="https://nixos.org/channels/nixos-unstable">nixos-unstable</literal>.
-     This corresponds to NixOS’s main development branch, and may thus see
-     radical changes between channel updates. It’s not recommended for
-     production systems.
-    </para>
-   </listitem>
-   <listitem>
-    <para>
-     <emphasis>Small channels</emphasis>, such as
-     <literal
-    xlink:href="https://nixos.org/channels/nixos-21.05-small">nixos-21.05-small</literal>
-     or
-     <literal
-    xlink:href="https://nixos.org/channels/nixos-unstable-small">nixos-unstable-small</literal>.
-     These are identical to the stable and unstable channels described above,
-     except that they contain fewer binary packages. This means they get
-     updated faster than the regular channels (for instance, when a critical
-     security patch is committed to NixOS’s source tree), but may require
-     more packages to be built from source than usual. They’re mostly
-     intended for server environments and as such contain few GUI applications.
-    </para>
-   </listitem>
-  </itemizedlist>
-  To see what channels are available, go to
-  <link xlink:href="https://nixos.org/channels"/>. (Note that the URIs of the
-  various channels redirect to a directory that contains the channel’s latest
-  version and includes ISO images and VirtualBox appliances.) Please note that
-  during the release process, channels that are not yet released will be
-  present here as well. See the Getting NixOS page
-  <link xlink:href="https://nixos.org/nixos/download.html"/> to find the newest
-  supported stable release.
- </para>
- <para>
-  When you first install NixOS, you’re automatically subscribed to the NixOS
-  channel that corresponds to your installation source. For instance, if you
-  installed from a 21.05 ISO, you will be subscribed to the
-  <literal>nixos-21.05</literal> channel. To see which NixOS channel you’re
-  subscribed to, run the following as root:
-<screen>
-<prompt># </prompt>nix-channel --list | grep nixos
-nixos https://nixos.org/channels/nixos-unstable
-</screen>
-  To switch to a different NixOS channel, do
-<screen>
-<prompt># </prompt>nix-channel --add https://nixos.org/channels/<replaceable>channel-name</replaceable> nixos
-</screen>
-  (Be sure to include the <literal>nixos</literal> parameter at the end.) For
-  instance, to use the NixOS 21.05 stable channel:
-<screen>
-<prompt># </prompt>nix-channel --add https://nixos.org/channels/nixos-21.05 nixos
-</screen>
-  If you have a server, you may want to use the “small” channel instead:
-<screen>
-<prompt># </prompt>nix-channel --add https://nixos.org/channels/nixos-21.05-small nixos
-</screen>
-  And if you want to live on the bleeding edge:
-<screen>
-<prompt># </prompt>nix-channel --add https://nixos.org/channels/nixos-unstable nixos
-</screen>
- </para>
- <para>
-  You can then upgrade NixOS to the latest version in your chosen channel by
-  running
-<screen>
-<prompt># </prompt>nixos-rebuild switch --upgrade
-</screen>
-  which is equivalent to the more verbose <literal>nix-channel --update nixos;
-  nixos-rebuild switch</literal>.
- </para>
- <note>
-  <para>
-   Channels are set per user. This means that running <literal> nix-channel
-   --add</literal> as a non root user (or without sudo) will not affect
-   configuration in <literal>/etc/nixos/configuration.nix</literal>
-  </para>
- </note>
- <warning>
-  <para>
-   It is generally safe to switch back and forth between channels. The only
-   exception is that a newer NixOS may also have a newer Nix version, which may
-   involve an upgrade of Nix’s database schema. This cannot be undone easily,
-   so in that case you will not be able to go back to your original channel.
-  </para>
- </warning>
- <section xml:id="sec-upgrading-automatic">
-  <title>Automatic Upgrades</title>
-
-  <para>
-   You can keep a NixOS system up-to-date automatically by adding the following
-   to <filename>configuration.nix</filename>:
-<programlisting>
-<xref linkend="opt-system.autoUpgrade.enable"/> = true;
-<xref linkend="opt-system.autoUpgrade.allowReboot"/> = true;
-</programlisting>
-   This enables a periodically executed systemd service named
-   <literal>nixos-upgrade.service</literal>. If the <literal>allowReboot</literal>
-   option is <literal>false</literal>, it runs <command>nixos-rebuild switch
-   --upgrade</command> to upgrade NixOS to the latest version in the current
-   channel. (To see when the service runs, see <command>systemctl list-timers</command>.)
-   If <literal>allowReboot</literal> is <literal>true</literal>, then the
-   system will automatically reboot if the new generation contains a different
-   kernel, initrd or kernel modules.
-   You can also specify a channel explicitly, e.g.
-<programlisting>
-<xref linkend="opt-system.autoUpgrade.channel"/> = https://nixos.org/channels/nixos-21.05;
-</programlisting>
-  </para>
- </section>
-</chapter>