try to not use hardcoded path

.gitea/workflows/check-flake.yaml

@@ -0,0 +1,38 @@
+name: Check Flake
+
+on: [push]
+
+env:
+  DEBIAN_FRONTEND: noninteractive
+  # PATH: /run/current-system/sw/bin/:/nix/var/nix/profiles/per-user/gitea-runner/profile/bin
+
+defaults:
+  run:
+    shell: /run/current-system/sw/bin/nix shell nixpkgs#nodejs-18_x
+
+jobs:
+  check-flake:
+    runs-on: nixos
+    steps:
+      # - run: node --version
+      # - name: Install basic dependencies
+      #   run: apt-get update && apt-get install -y --no-install-recommends sudo curl ca-certificates xz-utils
+
+      # - name: Install Nix
+      #   uses: https://github.com/cachix/install-nix-action@v20
+      #   with:
+      #     github_access_token: ${{ secrets.__GITHUB_TOKEN }}
+
+      # - name: Install dependencies
+      #   run: nix profile install nixpkgs#nodejs-18_x
+
+      - name: Checkout the repository
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+
+      # - name: Get ENV var names
+      #   run: printenv | cut -d'=' -f1
+
+      - name: Check Flake
+        run: nix flake check --show-trace

common/auto-update.nix

@@ -1,4 +1,4 @@
-{ config, pkgs, lib, ... }:
+{ config, lib, ... }:
 
 # Modify auto-update so that it pulls a flake
 
@@ -6,20 +6,10 @@ let
   cfg = config.system.autoUpgrade;
 in
 {
-  config = lib.mkIf cfg.enable (lib.mkMerge [
-    {
-      system.autoUpgrade = {
-        flake = "git+https://git.neet.dev/zuckerberg/nix-config.git";
-        flags = [ "--recreate-lock-file" "--no-write-lock-file" ]; # ignore lock file, just pull the latest
-
-        # dates = "03:40";
-        # kexecWindow = lib.mkDefault { lower = "01:00"; upper = "05:00"; };
-        # randomizedDelaySec = "45min";
-      };
-
-      system.autoUpgrade.allowKexec = lib.mkDefault true;
-
-      luks.enableKexec = cfg.allowKexec && builtins.length config.luks.devices > 0;
-    }
-  ]);
+  config = lib.mkIf cfg.enable {
+    system.autoUpgrade = {
+      flake = "git+https://git.neet.dev/zuckerberg/nix-config.git";
+      flags = [ "--recreate-lock-file" "--no-write-lock-file" ]; # ignore lock file, just pull the latest
+    };
+  };
 }

common/boot/default.nix

@@ -5,8 +5,6 @@
     ./firmware.nix
     ./efi.nix
     ./bios.nix
-    ./kexec-luks.nix
-    ./luks.nix
     ./remote-luks-unlock.nix
   ];
 }

common/boot/kexec-luks.nix

@@ -1,121 +0,0 @@
-# Allows kexec'ing as an alternative to rebooting for machines that
-# have luks encrypted partitions that need to be mounted at boot.
-# These luks partitions will be automatically unlocked, no password,
-# or any interaction needed whatsoever.
-
-# This is accomplished by fetching the luks key(s) while the system is running,
-# then building a temporary initrd that contains the luks key(s), and kexec'ing.
-
-{ config, lib, pkgs, ... }:
-
-{
-  options.luks = {
-    enableKexec = lib.mkEnableOption "Enable support for transparent passwordless kexec while using luks";
-  };
-
-  config = lib.mkIf config.luks.enableKexec {
-    luks.fallbackToPassword = true;
-    luks.disableKeyring = true;
-
-    boot.initrd.luks.devices = lib.listToAttrs
-      (builtins.map
-        (item:
-          {
-            name = item;
-            value = {
-              masterKeyFile = "/etc/${item}.key";
-            };
-          })
-        config.luks.deviceNames);
-
-    systemd.services.prepare-luks-kexec-image = {
-      description = "Prepare kexec automatic LUKS unlock on kexec reboot without a password";
-
-      wantedBy = [ "kexec.target" ];
-      unitConfig.DefaultDependencies = false;
-      serviceConfig.Type = "oneshot";
-
-      path = with pkgs; [ file kexec-tools coreutils-full cpio findutils gzip xz zstd lvm2 xxd gawk ];
-
-      # based on https://github.com/flowztul/keyexec
-      script = ''
-        system=/nix/var/nix/profiles/system
-        old_initrd=$(readlink -f "$system/initrd")
-
-        umask 0077
-        CRYPTROOT_TMPDIR="$(mktemp -d --tmpdir=/dev/shm)"
-
-        cleanup() {
-          shred -fu "$CRYPTROOT_TMPDIR/initrd_contents/etc/"*.key || true
-          shred -fu "$CRYPTROOT_TMPDIR/new_initrd" || true
-          shred -fu "$CRYPTROOT_TMPDIR/secret/"* || true
-          rm -rf "$CRYPTROOT_TMPDIR"
-        }
-        # trap cleanup INT TERM EXIT
-
-        mkdir -p "$CRYPTROOT_TMPDIR"
-        cd "$CRYPTROOT_TMPDIR"
-
-        # Determine the compression type of the initrd image
-        compression=$(file -b --mime-type "$old_initrd" | awk -F'/' '{print $2}')
-
-        # Decompress the initrd image based on its compression type
-        case "$compression" in
-          gzip)
-            gunzip -c "$old_initrd" > initrd.cpio
-            ;;
-          xz)
-            unxz -c "$old_initrd" > initrd.cpio
-            ;;
-          zstd)
-            zstd -d -c "$old_initrd" > initrd.cpio
-            ;;
-          *)
-            echo "Unsupported compression type: $compression"
-            exit 1
-            ;;
-        esac
-
-        # Extract the contents of the cpio archive
-        mkdir -p initrd_contents
-        cd initrd_contents
-        cpio -idv < ../initrd.cpio
-
-        # Generate keys and add them to the extracted initrd filesystem
-        luksDeviceNames=(${builtins.concatStringsSep " " config.luks.deviceNames})
-        for item in "''${luksDeviceNames[@]}"; do
-          dmsetup --showkeys table "$item" | cut -d ' ' -f5 | xxd -ps -g1 -r > "./etc/$item.key"
-        done
-
-        # Add normal initrd secrets too
-        ${lib.concatStringsSep "\n" (lib.mapAttrsToList (dest: source:
-            let source' = if source == null then dest else builtins.toString source; in
-              ''
-                mkdir -p $(dirname "./${dest}")
-                cp -a ${source'} "./${dest}"
-              ''
-          ) config.boot.initrd.secrets)
-        }
-
-        # Create a new cpio archive with the modified contents
-        find . | cpio -o -H newc -v > ../new_initrd.cpio
-
-        # Compress the new cpio archive using the original compression type
-        cd ..
-        case "$compression" in
-          gzip)
-            gunzip -c new_initrd.cpio > new_initrd
-            ;;
-          xz)
-            unxz -c new_initrd.cpio > new_initrd
-            ;;
-          zstd)
-            zstd -c new_initrd.cpio > new_initrd
-            ;;
-        esac
-
-        kexec --load "$system/kernel" --append "init=$system/init ${builtins.concatStringsSep " " config.boot.kernelParams}" --initrd "$CRYPTROOT_TMPDIR/new_initrd"
-      '';
-    };
-  };
-}

common/boot/luks.nix

@@ -1,74 +0,0 @@
-# Makes it a little easier to configure luks partitions for boot
-# Additionally, this solves a circular dependency between kexec luks
-# and NixOS's luks module.
-
-{ config, lib, ... }:
-
-let
-  cfg = config.luks;
-
-  deviceCount = builtins.length cfg.devices;
-
-  deviceMap = lib.imap
-    (i: item: {
-      device = item;
-      name =
-        if deviceCount == 1 then "enc-pv"
-        else "enc-pv${builtins.toString (i + 1)}";
-    })
-    cfg.devices;
-in
-{
-  options.luks = {
-    devices = lib.mkOption {
-      type = lib.types.listOf lib.types.str;
-      default = [ ];
-    };
-
-    allowDiscards = lib.mkOption {
-      type = lib.types.bool;
-      default = true;
-    };
-
-    fallbackToPassword = lib.mkEnableOption
-      "Fallback to interactive passphrase prompt if the cannot be found.";
-
-    disableKeyring = lib.mkEnableOption
-      "When opening LUKS2 devices, don't use the kernel keyring";
-
-    # set automatically, don't touch
-    deviceNames = lib.mkOption {
-      type = lib.types.listOf lib.types.str;
-    };
-  };
-
-  config = lib.mkMerge [
-    {
-      assertions = [
-        {
-          assertion = deviceCount == builtins.length (builtins.attrNames config.boot.initrd.luks.devices);
-          message = ''
-            All luks devices must be specified using `luks.devices` not `boot.initrd.luks.devices`.
-          '';
-        }
-      ];
-    }
-    (lib.mkIf (deviceCount != 0) {
-      luks.deviceNames = builtins.map (device: device.name) deviceMap;
-
-      boot.initrd.luks.devices = lib.listToAttrs (
-        builtins.map
-          (item:
-            {
-              name = item.name;
-              value = {
-                device = item.device;
-                allowDiscards = cfg.allowDiscards;
-                fallbackToPassword = cfg.fallbackToPassword;
-                disableKeyring = cfg.disableKeyring;
-              };
-            })
-          deviceMap);
-    })
-  ];
-}

common/boot/remote-luks-unlock.nix

@@ -33,6 +33,11 @@ in
   };
 
   config = lib.mkIf cfg.enable {
+    # boot.initrd.luks.devices.${cfg.device.name} = {
+    #   device = cfg.device.path;
+    #   allowDiscards = cfg.device.allowDiscards;
+    # };
+
     # Unlock LUKS disk over ssh
     boot.initrd.network.enable = true;
     boot.initrd.kernelModules = cfg.kernelModules;

common/server/gitea-runner.nix

@@ -11,12 +11,6 @@ in
       type = lib.types.str;
       description = lib.mdDoc "gitea runner data directory.";
     };
-    instanceUrl = lib.mkOption {
-      type = lib.types.str;
-    };
-    registrationTokenFile = lib.mkOption {
-      type = lib.types.path;
-    };
   };
 
   config = lib.mkIf cfg.enable {
@@ -35,13 +29,6 @@ in
     };
     users.groups.gitea-runner = { };
 
-    # registration token
-    services.gitea-runner.registrationTokenFile = "/run/agenix/gitea-runner-registration-token";
-    age.secrets.gitea-runner-registration-token = {
-      file = ../../secrets/gitea-runner-registration-token.age;
-      owner = "gitea-runner";
-    };
-
     systemd.services.gitea-runner = {
       description = "Gitea Runner";
 
@@ -57,40 +44,7 @@ in
 
       path = with pkgs; [ gitea-actions-runner ];
 
-      # based on https://gitea.com/gitea/act_runner/src/branch/main/run.sh
       script = ''
-        . ${cfg.registrationTokenFile}
-
-        if [[ ! -s .runner ]]; then
-          try=$((try + 1))
-          success=0
-
-          LOGFILE="$(mktemp)"
-
-          # The point of this loop is to make it simple, when running both act_runner and gitea in docker,
-          # for the act_runner to wait a moment for gitea to become available before erroring out.  Within
-          # the context of a single docker-compose, something similar could be done via healthchecks, but
-          # this is more flexible.
-          while [[ $success -eq 0 ]] && [[ $try -lt ''${10:-10} ]]; do
-            act_runner register \
-              --instance "${cfg.instanceUrl}" \
-              --token    "$GITEA_RUNNER_REGISTRATION_TOKEN" \
-              --name     "${config.networking.hostName}" \
-              --no-interactive > $LOGFILE 2>&1
-
-            cat $LOGFILE
-
-            cat $LOGFILE | grep 'Runner registered successfully' > /dev/null
-            if [[ $? -eq 0 ]]; then
-              echo "SUCCESS"
-              success=1
-            else
-              echo "Waiting to retry ..."
-              sleep 5
-            fi
-          done
-        fi
-
         exec act_runner daemon
       '';
     };

flake.nix

@@ -55,7 +55,7 @@
     {
       nixosConfigurations =
         let
-          modules = system: hostname: with inputs; [
+          modules = system: with inputs; [
             ./common
             simple-nixos-mailserver.nixosModule
             agenix.nixosModules.default
@@ -63,13 +63,9 @@
             archivebox.nixosModule
             nix-index-database.nixosModules.nix-index
             ({ lib, ... }: {
-              config = {
-                environment.systemPackages = [
-                  agenix.packages.${system}.agenix
-                ];
-
-                networking.hostName = hostname;
-              };
+              config.environment.systemPackages = [
+                agenix.packages.${system}.agenix
+              ];
 
               # because nixos specialArgs doesn't work for containers... need to pass in inputs a different way
               options.inputs = lib.mkOption { default = inputs; };
@@ -77,9 +73,9 @@
             })
           ];
 
-          mkSystem = system: nixpkgs: path: hostname:
+          mkSystem = system: nixpkgs: path:
             let
-              allModules = modules system hostname;
+              allModules = modules system;
 
               # allow patching nixpkgs, remove this hack once this is solved: https://github.com/NixOS/nix/issues/3920
               patchedNixpkgsSrc = nixpkgs.legacyPackages.${system}.applyPatches {
@@ -87,7 +83,6 @@
                 src = nixpkgs;
                 patches = [
                   inputs.nixpkgs-hostapd-pr
-                  ./patches/kexec-luks.patch
                 ];
               };
               patchedNixpkgs = nixpkgs.lib.fix (self: (import "${patchedNixpkgsSrc}/flake.nix").outputs { self = nixpkgs; });
@@ -104,7 +99,7 @@
         in
         nixpkgs.lib.mapAttrs
           (hostname: cfg:
-            mkSystem cfg.arch nixpkgs cfg.configurationPath hostname)
+            mkSystem cfg.arch nixpkgs cfg.configurationPath)
           machines;
 
       packages =

machines/phil/default.nix

@@ -5,10 +5,6 @@
     ./hardware-configuration.nix
   ];
 
-  services.gitea-runner = {
-    enable = true;
-    instanceUrl = "https://git.neet.dev";
-  };
-
-  system.autoUpgrade.enable = true;
+  networking.hostName = "phil";
+  services.gitea-runner.enable = true;
 }

machines/phil/hardware-configuration.nix

@@ -20,7 +20,10 @@
   boot.kernelModules = [ ];
   boot.extraModulePackages = [ ];
 
-  luks.devices = [ "/dev/disk/by-uuid/d26c1820-4c39-4615-98c2-51442504e194" ];
+  boot.initrd.luks.devices."enc-pv" = {
+    device = "/dev/disk/by-uuid/d26c1820-4c39-4615-98c2-51442504e194";
+    allowDiscards = true;
+  };
 
   fileSystems."/" =
     {

machines/ponyo/default.nix

@@ -5,10 +5,9 @@
     ./hardware-configuration.nix
   ];
 
+  networking.hostName = "ponyo";
+
   system.autoUpgrade.enable = true;
-  # I want to manually trigger kexec updates for now on ponyo
-  system.autoUpgrade.allowKexec = false;
-  luks.enableKexec = true;
 
   # p2p mesh network
   services.tailscale.exitNode = true;

machines/ponyo/hardware-configuration.nix

@@ -19,15 +19,12 @@
   };
 
   remoteLuksUnlock.enable = true;
-
-  luks.devices = [
-    "/dev/disk/by-uuid/4cc36be4-dbff-4afe-927d-69bf4637bae2"
-    "/dev/disk/by-uuid/e52b01b3-81c8-4bb2-ae7e-a3d9c793cb00"
-  ];
+  boot.initrd.luks.devices."enc-pv".device = "/dev/disk/by-uuid/4cc36be4-dbff-4afe-927d-69bf4637bae2";
+  boot.initrd.luks.devices."enc-pv2".device = "/dev/disk/by-uuid/e52b01b3-81c8-4bb2-ae7e-a3d9c793cb00"; # expanded disk
 
   fileSystems."/" =
     {
-      device = "/dev/mapper/enc-pv1";
+      device = "/dev/mapper/enc-pv";
       fsType = "btrfs";
     };
 

machines/ray/default.nix

@@ -5,6 +5,8 @@
     ./hardware-configuration.nix
   ];
 
+  networking.hostName = "ray";
+
   # for luks onlock over tor
   services.tor.enable = true;
   services.tor.client.enable = true;

machines/ray/hardware-configuration.nix

@@ -36,7 +36,10 @@
 
   # disks
   remoteLuksUnlock.enable = true;
-  luks.devices = [ "/dev/disk/by-uuid/c1822e5f-4137-44e1-885f-954e926583ce" ];
+  boot.initrd.luks.devices."enc-pv" = {
+    device = "/dev/disk/by-uuid/c1822e5f-4137-44e1-885f-954e926583ce";
+    allowDiscards = true;
+  };
   fileSystems."/" =
     {
       device = "/dev/vg/root";

machines/router/default.nix

@@ -11,6 +11,8 @@
   # https://github.com/skogsbrus/os/blob/master/sys/router.nix
   # http://trac.gateworks.com/wiki/wireless/wifi 
 
+  networking.hostName = "router";
+
   system.autoUpgrade.enable = true;
 
   services.tailscale.exitNode = true;

machines/router/hardware-configuration.nix

@@ -32,7 +32,7 @@
 
   # disks
   remoteLuksUnlock.enable = true;
-  luks.devices = [ "/dev/disk/by-uuid/9b090551-f78e-45ca-8570-196ed6a4af0c" ];
+  boot.initrd.luks.devices."enc-pv".device = "/dev/disk/by-uuid/9b090551-f78e-45ca-8570-196ed6a4af0c";
   fileSystems."/" =
     {
       device = "/dev/disk/by-uuid/421c82b9-d67c-4811-8824-8bb57cb10fce";

machines/storage/s0/default.nix

@@ -5,7 +5,14 @@
     ./hardware-configuration.nix
   ];
 
-  system.autoUpgrade.enable = true;
+  networking.hostName = "s0";
+
+  # system.autoUpgrade.enable = true;
+
+  # gitea runner and allow it to build ARM derivations
+  services.gitea-runner.enable = true;
+  boot.binfmt.emulatedSystems = [ "aarch64-linux" ];
+  nix.gc.automatic = lib.mkForce false; # allow the nix store to serve as a build cache
 
   services.iperf3.enable = true;
   services.iperf3.openFirewall = true;

machines/storage/s0/hardware-configuration.nix

@@ -7,7 +7,7 @@
     ];
 
   # boot
-  boot.loader.systemd-boot.enable = true;
+  efi.enable = true;
   boot.initrd.availableKernelModules = [ "xhci_pci" "ahci" "nvme" "usb_storage" "uas" "sd_mod" "rtsx_pci_sdmmc" ];
   boot.initrd.kernelModules = [ ];
   boot.kernelModules = [ "kvm-intel" ];
@@ -25,12 +25,10 @@
 
   # luks
   remoteLuksUnlock.enable = true;
-  luks.devices = [
-    "/dev/disk/by-uuid/d52e99a9-8825-4d0a-afc1-8edbef7e0a86"
-    "/dev/disk/by-uuid/f7275585-7760-4230-97de-36704b9a2aa3"
-    "/dev/disk/by-uuid/5d1002b8-a0ed-4a1c-99f5-24b8816d9e38"
-    "/dev/disk/by-uuid/e2c7402a-e72c-4c4a-998f-82e4c10187bc"
-  ];
+  boot.initrd.luks.devices."enc-pv1".device = "/dev/disk/by-uuid/d52e99a9-8825-4d0a-afc1-8edbef7e0a86";
+  boot.initrd.luks.devices."enc-pv2".device = "/dev/disk/by-uuid/f7275585-7760-4230-97de-36704b9a2aa3";
+  boot.initrd.luks.devices."enc-pv3".device = "/dev/disk/by-uuid/5d1002b8-a0ed-4a1c-99f5-24b8816d9e38";
+  boot.initrd.luks.devices."enc-pv4".device = "/dev/disk/by-uuid/e2c7402a-e72c-4c4a-998f-82e4c10187bc";
 
   # mounts
   fileSystems."/" =

patches/kexec-luks.patch

@@ -1,264 +0,0 @@
-diff --git a/nixos/modules/system/boot/luksroot.nix b/nixos/modules/system/boot/luksroot.nix
-index b8f36538e70..cc320a04c70 100644
---- a/nixos/modules/system/boot/luksroot.nix
-+++ b/nixos/modules/system/boot/luksroot.nix
-@@ -146,6 +146,7 @@ let
-     csopen = "cryptsetup luksOpen ${dev.device} ${dev.name}"
-            + optionalString dev.allowDiscards " --allow-discards"
-            + optionalString dev.bypassWorkqueues " --perf-no_read_workqueue --perf-no_write_workqueue"
-+           + optionalString dev.disableKeyring " --disable-keyring"
-            + optionalString (dev.header != null) " --header=${dev.header}";
-     cschange = "cryptsetup luksChangeKey ${dev.device} ${optionalString (dev.header != null) "--header=${dev.header}"}";
-     fido2luksCredentials = dev.fido2.credentials ++ optional (dev.fido2.credential != null) dev.fido2.credential;
-@@ -243,6 +244,26 @@ let
-                do_open_passphrase
-             fi
-         fi
-+        '' else if (dev.masterKeyFile != null) then ''
-+        if wait_target "key file" ${dev.masterKeyFile}; then
-+            ${csopen} --master-key-file=${dev.masterKeyFile}
-+            cs_status=$?
-+            if [ $cs_status -ne 0 ]; then
-+              echo "Key File ${dev.masterKeyFile} failed!"
-+              if ! try_empty_passphrase; then
-+                ${if dev.fallbackToPassword then "echo" else "die"} "${dev.masterKeyFile} is unavailable"
-+                echo " - failing back to interactive password prompt"
-+                do_open_passphrase
-+              fi
-+            fi
-+        else
-+            # If the key file never shows up we should also try the empty passphrase
-+            if ! try_empty_passphrase; then
-+               ${if dev.fallbackToPassword then "echo" else "die"} "${dev.masterKeyFile} is unavailable"
-+               echo " - failing back to interactive password prompt"
-+               do_open_passphrase
-+            fi
-+        fi
-         '' else ''
-            if ! try_empty_passphrase; then
-               do_open_passphrase
-@@ -625,6 +646,15 @@ in
-             '';
-           };
- 
-+          masterKeyFile = mkOption {
-+            default = null;
-+            type = types.nullOr types.str;
-+            description = lib.mdDoc ''
-+              The name of the file (can be a raw device or a partition) that
-+              should be used as the master decryption key for the encrypted device.
-+            '';
-+          };
-+
-           tryEmptyPassphrase = mkOption {
-             default = false;
-             type = types.bool;
-@@ -700,6 +730,15 @@ in
-             '';
-           };
- 
-+          disableKeyring = mkOption {
-+            default = false;
-+            type = types.bool;
-+            description = lib.mdDoc ''
-+              Disables using the kernel keyring for LUKS2 disks.
-+              This is already the default behavior for LUKS1
-+            '';
-+          };
-+
-           fallbackToPassword = mkOption {
-             default = false;
-             type = types.bool;
-diff --git a/nixos/modules/tasks/auto-upgrade.nix b/nixos/modules/tasks/auto-upgrade.nix
-index 29e3e313336..050bf09c208 100644
---- a/nixos/modules/tasks/auto-upgrade.nix
-+++ b/nixos/modules/tasks/auto-upgrade.nix
-@@ -4,7 +4,8 @@ with lib;
- 
- let cfg = config.system.autoUpgrade;
- 
--in {
-+in
-+{
- 
-   options = {
- 
-@@ -22,7 +23,7 @@ in {
-       };
- 
-       operation = mkOption {
--        type = types.enum ["switch" "boot"];
-+        type = types.enum [ "switch" "boot" ];
-         default = "switch";
-         example = "boot";
-         description = lib.mdDoc ''
-@@ -86,14 +87,14 @@ in {
-         '';
-       };
- 
--      allowReboot = mkOption {
-+      allowKexec = mkOption {
-         default = false;
-         type = types.bool;
-         description = lib.mdDoc ''
--          Reboot the system into the new generation instead of a switch
-+          kexec the system into the new generation instead of a switch
-           if the new generation uses a different kernel, kernel modules
-           or initrd than the booted system.
--          See {option}`rebootWindow` for configuring the times at which a reboot is allowed.
-+          See {option}`kexecWindow` for configuring the times at which a kexec is allowed.
-         '';
-       };
- 
-@@ -109,25 +110,25 @@ in {
-         '';
-       };
- 
--      rebootWindow = mkOption {
-+      kexecWindow = mkOption {
-         description = lib.mdDoc ''
-           Define a lower and upper time value (in HH:MM format) which
--          constitute a time window during which reboots are allowed after an upgrade.
--          This option only has an effect when {option}`allowReboot` is enabled.
--          The default value of `null` means that reboots are allowed at any time.
-+          constitute a time window during which kexecs are allowed after an upgrade.
-+          This option only has an effect when {option}`allowKexec` is enabled.
-+          The default value of `null` means that kexecs are allowed at any time.
-         '';
-         default = null;
-         example = { lower = "01:00"; upper = "05:00"; };
-         type = with types; nullOr (submodule {
-           options = {
-             lower = mkOption {
--              description = lib.mdDoc "Lower limit of the reboot window";
-+              description = lib.mdDoc "Lower limit of the kexec window";
-               type = types.strMatching "[[:digit:]]{2}:[[:digit:]]{2}";
-               example = "01:00";
-             };
- 
-             upper = mkOption {
--              description = lib.mdDoc "Upper limit of the reboot window";
-+              description = lib.mdDoc "Upper limit of the kexec window";
-               type = types.strMatching "[[:digit:]]{2}:[[:digit:]]{2}";
-               example = "05:00";
-             };
-@@ -165,12 +166,12 @@ in {
-     }];
- 
-     system.autoUpgrade.flags = (if cfg.flake == null then
--        [ "--no-build-output" ] ++ optionals (cfg.channel != null) [
--          "-I"
--          "nixpkgs=${cfg.channel}/nixexprs.tar.xz"
--        ]
--      else
--        [ "--flake ${cfg.flake}" ]);
-+      [ "--no-build-output" ] ++ optionals (cfg.channel != null) [
-+        "-I"
-+        "nixpkgs=${cfg.channel}/nixexprs.tar.xz"
-+      ]
-+    else
-+      [ "--flake ${cfg.flake}" ]);
- 
-     systemd.services.nixos-upgrade = {
-       description = "NixOS Upgrade";
-@@ -195,54 +196,56 @@ in {
-         config.programs.ssh.package
-       ];
- 
--      script = let
--        nixos-rebuild = "${config.system.build.nixos-rebuild}/bin/nixos-rebuild";
--        date     = "${pkgs.coreutils}/bin/date";
--        readlink = "${pkgs.coreutils}/bin/readlink";
--        shutdown = "${config.systemd.package}/bin/shutdown";
--        upgradeFlag = optional (cfg.channel == null) "--upgrade";
--      in if cfg.allowReboot then ''
--        ${nixos-rebuild} boot ${toString (cfg.flags ++ upgradeFlag)}
--        booted="$(${readlink} /run/booted-system/{initrd,kernel,kernel-modules})"
--        built="$(${readlink} /nix/var/nix/profiles/system/{initrd,kernel,kernel-modules})"
--
--        ${optionalString (cfg.rebootWindow != null) ''
--          current_time="$(${date} +%H:%M)"
--
--          lower="${cfg.rebootWindow.lower}"
--          upper="${cfg.rebootWindow.upper}"
--
--          if [[ "''${lower}" < "''${upper}" ]]; then
--            if [[ "''${current_time}" > "''${lower}" ]] && \
--               [[ "''${current_time}" < "''${upper}" ]]; then
--              do_reboot="true"
-+      script =
-+        let
-+          nixos-rebuild = "${config.system.build.nixos-rebuild}/bin/nixos-rebuild";
-+          date = "${pkgs.coreutils}/bin/date";
-+          readlink = "${pkgs.coreutils}/bin/readlink";
-+          systemctl_kexec = "${config.systemd.package}/bin/systemctl kexec";
-+          upgradeFlag = optional (cfg.channel == null) "--upgrade";
-+        in
-+        if cfg.allowKexec then ''
-+          ${nixos-rebuild} boot ${toString (cfg.flags ++ upgradeFlag)}
-+          booted="$(${readlink} /run/booted-system/{initrd,kernel,kernel-modules})"
-+          built="$(${readlink} /nix/var/nix/profiles/system/{initrd,kernel,kernel-modules})"
-+
-+          ${optionalString (cfg.kexecWindow != null) ''
-+            current_time="$(${date} +%H:%M)"
-+
-+            lower="${cfg.kexecWindow.lower}"
-+            upper="${cfg.kexecWindow.upper}"
-+
-+            if [[ "''${lower}" < "''${upper}" ]]; then
-+              if [[ "''${current_time}" > "''${lower}" ]] && \
-+                 [[ "''${current_time}" < "''${upper}" ]]; then
-+                do_kexec="true"
-+              else
-+                do_kexec="false"
-+              fi
-             else
--              do_reboot="false"
-+              # lower > upper, so we are crossing midnight (e.g. lower=23h, upper=6h)
-+              # we want to reboot if cur > 23h or cur < 6h
-+              if [[ "''${current_time}" < "''${upper}" ]] || \
-+                 [[ "''${current_time}" > "''${lower}" ]]; then
-+                do_kexec="true"
-+              else
-+                do_kexec="false"
-+              fi
-             fi
-+          ''}
-+
-+          if [ "''${booted}" = "''${built}" ]; then
-+            ${nixos-rebuild} ${cfg.operation} ${toString cfg.flags}
-+          ${optionalString (cfg.kexecWindow != null) ''
-+            elif [ "''${do_kexec}" != true ]; then
-+              echo "Outside of configured kexec window, skipping."
-+          ''}
-           else
--            # lower > upper, so we are crossing midnight (e.g. lower=23h, upper=6h)
--            # we want to reboot if cur > 23h or cur < 6h
--            if [[ "''${current_time}" < "''${upper}" ]] || \
--               [[ "''${current_time}" > "''${lower}" ]]; then
--              do_reboot="true"
--            else
--              do_reboot="false"
--            fi
-+            ${systemctl_kexec}
-           fi
--        ''}
--
--        if [ "''${booted}" = "''${built}" ]; then
--          ${nixos-rebuild} ${cfg.operation} ${toString cfg.flags}
--        ${optionalString (cfg.rebootWindow != null) ''
--          elif [ "''${do_reboot}" != true ]; then
--            echo "Outside of configured reboot window, skipping."
--        ''}
--        else
--          ${shutdown} -r +1
--        fi
--      '' else ''
--        ${nixos-rebuild} ${cfg.operation} ${toString (cfg.flags ++ upgradeFlag)}
--      '';
-+        '' else ''
-+          ${nixos-rebuild} ${cfg.operation} ${toString (cfg.flags ++ upgradeFlag)}
-+        '';
- 
-       startAt = cfg.dates;
-