nixos containers: disable NixOS manual in container config. (#75659)

This makes ~2.5x speed up of an empty container instantiate, hence reduces
rebuild time of system with many declarative containers.

Note that this doesn't affect production systems much, becaseu those most
likely already include `minimal.nix` profile.

2 files changed, 9 insertions, 0 deletions

diff --git a/nixos/doc/manual/release-notes/rl-2003.xml b/nixos/doc/manual/release-notes/rl-2003.xml
index 7791a72d263a..2a38b2adbbb4 100644
--- a/nixos/doc/manual/release-notes/rl-2003.xml
+++ b/nixos/doc/manual/release-notes/rl-2003.xml
@@ -243,6 +243,14 @@
      choices (whether to perform the action as themselves with wheel permissions, or as the root user).
     </para>
    </listitem>
+   <listitem>
+    <para>
+     NixOS containers no longer build NixOS manual by default. This saves evaluation time,
+     especially if there are many declarative containers defined. Note that this is already done
+     when <literal>&lt;nixos/modules/profiles/minimal.nix&gt;</literal> module is included
+     in container config.
+    </para>
+   </listitem>
   </itemizedlist>
  </section>
 
diff --git a/nixos/modules/virtualisation/container-config.nix b/nixos/modules/virtualisation/container-config.nix
index f7a37d8c9f3b..6ff6bdd30c20 100644
--- a/nixos/modules/virtualisation/container-config.nix
+++ b/nixos/modules/virtualisation/container-config.nix
@@ -10,6 +10,7 @@ with lib;
     nix.optimise.automatic = mkDefault false; # the store is host managed
     services.udisks2.enable = mkDefault false;
     powerManagement.enable = mkDefault false;
+    documentation.nixos.enable = mkDefault false;
 
     networking.useHostResolvConf = mkDefault true;