Unverified Commit 115c1d69 authored by Jared Baur's avatar Jared Baur
Browse files

nixos/systemd: add presets to ignore all other presets 

One of the main premises of NixOS is being able to declaratively specify
the services enabled/running on a machine. Since systemd presets allow
to bypass this this declarative nature, add a single preset with the
highest priority (prefixed with "00") that makes systemd ignore all
other presets.
parent 2b982b99

nixos/modules/system/boot/systemd.nix

+9 −0
Original line number Diff line number Diff line
@@ -566,6 +566,15 @@ in 
      "systemd/user-generators" = { source = hooks "user-generators" cfg.user.generators; };

      "systemd/system-generators" = { source = hooks "system-generators" cfg.generators; };

      "systemd/system-shutdown" = { source = hooks "system-shutdown" cfg.shutdown; };



      # Ignore all other preset files so systemd doesn't try to enable/disable

      # units during runtime.

      "systemd/system-preset/00-nixos.preset".text = ''

        ignore *

      '';

      "systemd/user-preset/00-nixos.preset".text = ''

        ignore *

      '';

    });



    services.dbus.enable = true;

nixos/tests/systemd.nix

+9 −1
Original line number Diff line number Diff line
@@ -75,9 +75,13 @@ import ./make-test-python.nix ({ pkgs, ... }: { 
      rebootTime = "10min";

      kexecTime = "5min";

    };



    environment.etc."systemd/system-preset/10-testservice.preset".text = ''

      disable ${config.systemd.services.testservice1.name}

    '';

  };



  testScript = ''

  testScript = { nodes, ... }: ''

    import re

    import subprocess
@@ -213,5 +217,9 @@ import ./make-test-python.nix ({ pkgs, ... }: { 
    with subtest("systemd environment is properly set"):

        machine.systemctl("daemon-reexec")  # Rewrites /proc/1/environ

        machine.succeed("grep -q TZDIR=/etc/zoneinfo /proc/1/environ")



    with subtest("systemd presets are ignored"):

        machine.succeed("systemctl preset ${nodes.machine.systemd.services.testservice1.name}")

        machine.succeed("test -e /etc/systemd/system/${nodes.machine.systemd.services.testservice1.name}")

  '';

})