nixos/systemd-sysupdate: init

nixos/doc/manual/release-notes/rl-2311.section.md

···
 
 - [ebusd](https://ebusd.eu), a daemon for handling communication with eBUS devices connected to a 2-wire bus system (“energy bus” used by numerous heating systems). Available as [services.ebusd](#opt-services.ebusd.enable).
 
+- [systemd-sysupdate](https://www.freedesktop.org/software/systemd/man/systemd-sysupdate.html), atomically updates the host OS, container images, portable service images or other sources. Available as [systemd.sysupdate](opt-systemd.sysupdate).
 
 ## Backward Incompatibilities {#sec-release-23.11-incompatibilities}
 

nixos/modules/module-list.nix

···
   ./system/boot/systemd/oomd.nix
   ./system/boot/systemd/repart.nix
   ./system/boot/systemd/shutdown.nix
+  ./system/boot/systemd/sysupdate.nix
   ./system/boot/systemd/tmpfiles.nix
   ./system/boot/systemd/user.nix
   ./system/boot/systemd/userdbd.nix

nixos/modules/system/boot/systemd/sysupdate.nix

···
+{ config, lib, pkgs, utils, ... }:
+
+let
+  cfg = config.systemd.sysupdate;
+
+  format = pkgs.formats.ini { };
+
+  listOfDefinitions = lib.mapAttrsToList
+    (name: format.generate "${name}.conf")
+    (lib.filterAttrs (k: _: !(lib.hasPrefix "_" k)) cfg.transfers);
+
+  definitionsDirectory = pkgs.runCommand "sysupdate.d" { } ''
+    mkdir -p $out
+    ${(lib.concatStringsSep "\n"
+      (map (pkg: "cp ${pkg} $out/${pkg.name}") listOfDefinitions)
+    )}
+  '';
+in
+{
+  options.systemd.sysupdate = {
+
+    enable = lib.mkEnableOption (lib.mdDoc "systemd-sysupdate") // {
+      description = lib.mdDoc ''
+        Atomically update the host OS, container images, portable service
+        images or other sources.
+
+        If enabled, updates are triggered in regular intervals via a
+        `systemd.timer` unit.
+
+        Please see
+        <https://www.freedesktop.org/software/systemd/man/systemd-sysupdate.html>
+        for more details.
+      '';
+    };
+
+    timerConfig = utils.systemdUtils.unitOptions.timerOptions.options.timerConfig // {
+      default = { };
+      description = lib.mdDoc ''
+        The timer configuration for performing the update.
+
+        By default, the upstream configuration is used:
+        <https://github.com/systemd/systemd/blob/main/units/systemd-sysupdate.timer>
+      '';
+    };
+
+    reboot = {
+      enable = lib.mkEnableOption (lib.mdDoc "automatically rebooting after an update") // {
+        description = lib.mdDoc ''
+          Whether to automatically reboot after an update.
+
+          If set to `true`, the system will automatically reboot via a
+          `systemd.timer` unit but only after a new version was installed.
+
+          This uses a unit completely separate from the one performing the
+          update because it is typically advisable to download updates
+          regularly while the system is up, but delay reboots until the
+          appropriate time (i.e. typically at night).
+
+          Set this to `false` if you do not want to reboot after an update. This
+          is useful when you update a container image or another source where
+          rebooting is not necessary in order to finalize the update.
+        '';
+      };
+
+      timerConfig = utils.systemdUtils.unitOptions.timerOptions.options.timerConfig // {
+        default = { };
+        description = lib.mdDoc ''
+          The timer configuration for rebooting after an update.
+
+          By default, the upstream configuration is used:
+          <https://github.com/systemd/systemd/blob/main/units/systemd-sysupdate-reboot.timer>
+        '';
+      };
+    };
+
+    transfers = lib.mkOption {
+      type = with lib.types; attrsOf format.type;
+      default = { };
+      example = {
+        "10-uki.conf" = {
+          Transfer = {
+            ProtectVersion = "%A";
+          };
+
+          Source = {
+            Type = "url-file";
+            Path = "https://download.example.com/";
+            MatchPattern = "[e-mail]";
+          };
+
+          Target = {
+            Type = "regular-file";
+            Path = "/EFI/Linux";
+            PathRelativeTo = "boot";
+            MatchPattern = ''
+              nixos_@v+@[e-mail]"; \
+              nixos_@[e-mail] \
+              [e-mail]
+            '';
+            Mode = "0444";
+            TriesLeft = 3;
+            TriesDone = 0;
+            InstancesMax = 2;
+          };
+        };
+      };
+      description = lib.mdDoc ''
+        Specify transfers as a set of the names of the transfer files as the
+        key and the configuration as its value. The configuration can use all
+        upstream options. See
+        <https://www.freedesktop.org/software/systemd/man/sysupdate.d.html>
+        for all available options.
+      '';
+    };
+
+  };
+
+  config = lib.mkIf cfg.enable {
+
+    systemd.additionalUpstreamSystemUnits = [
+      "systemd-sysupdate.service"
+      "systemd-sysupdate.timer"
+      "systemd-sysupdate-reboot.service"
+      "systemd-sysupdate-reboot.timer"
+    ];
+
+    systemd.timers = {
+      "systemd-sysupdate" = {
+        wantedBy = [ "timers.target" ];
+        timerConfig = cfg.timerConfig;
+      };
+      "systemd-sysupdate-reboot" = lib.mkIf cfg.reboot.enable {
+        wantedBy = [ "timers.target" ];
+        timerConfig = cfg.reboot.timerConfig;
+      };
+    };
+
+    environment.etc."sysupdate.d".source = definitionsDirectory;
+  };
+
+  meta.maintainers = with lib.maintainers; [ nikstur ];
+}