Add ISO build

flake.nix

@@ -87,11 +87,18 @@
       mkKexec = system:
         (nixpkgs.lib.nixosSystem {
           inherit system;
-          modules = [ ./machines/kexec.nix ];
+          modules = [ ./machines/ephemeral/kexec.nix ];
         }).config.system.build.kexec_tarball;
+      mkIso = system:
+        (nixpkgs.lib.nixosSystem {
+          inherit system;
+          modules = [ ./machines/ephemeral/iso.nix ];
+        }).config.system.build.isoImage;
     in {
       "x86_64-linux"."kexec" = mkKexec "x86_64-linux";
+      "x86_64-linux"."iso" = mkIso "x86_64-linux";
       "aarch64-linux"."kexec" = mkKexec "aarch64-linux";
+      "aarch64-linux"."iso" = mkIso "aarch64-linux";
     };
   };
 }

machines/ephemeral/iso.nix

@@ -0,0 +1,12 @@
+{ modulesPath, ... }:
+
+{
+  imports = [
+    (modulesPath + "/installer/cd-dvd/iso-image.nix")
+    ./minimal.nix
+  ];
+
+  isoImage.makeUsbBootable = true;
+
+  networking.hostName = "iso";
+}

machines/ephemeral/kexec.nix

@@ -6,8 +6,11 @@
   imports = [
     (modulesPath + "/installer/netboot/netboot.nix")
     (modulesPath + "/profiles/qemu-guest.nix")
+    ./minimal.nix
   ];
 
+  networking.hostName = "kexec";
+
   # stripped down version of https://github.com/cleverca22/nix-tests/tree/master/kexec
   system.build = rec {
     image = pkgs.runCommand "image" { buildInputs = [ pkgs.nukeReferences ]; } ''
@@ -42,31 +45,4 @@
       contents = [ ];
     };
   };
-
-  boot.initrd.availableKernelModules = [ "ata_piix" "uhci_hcd" "e1000" "e1000e" "virtio_pci" "r8169" ];
-  boot.kernelParams = [
-    "panic=30" "boot.panic_on_fail" # reboot the machine upon fatal boot issues
-    "console=ttyS0" # enable serial console
-    "console=tty1"
-  ];
-  boot.kernel.sysctl."vm.overcommit_memory" = "1";
-
-  environment.systemPackages = with pkgs; [
-    cryptsetup
-    btrfs-progs
-  ];
-  environment.variables.GC_INITIAL_HEAP_SIZE = "1M";
-
-  networking.useDHCP = true;
-
-  networking.hostName = "kexec";
-
-  services.openssh = {
-    enable = true;
-    challengeResponseAuthentication = false;
-    passwordAuthentication = false;
-  };
-
-  services.getty.autologinUser = "root";
-  users.users.root.openssh.authorizedKeys.keys = (import ../common/ssh.nix).users;
 }

machines/ephemeral/minimal.nix

@@ -0,0 +1,28 @@
+{ pkgs, ... }:
+
+{
+  boot.initrd.availableKernelModules = [ "ata_piix" "uhci_hcd" "e1000" "e1000e" "virtio_pci" "r8169" ];
+  boot.kernelParams = [
+    "panic=30" "boot.panic_on_fail" # reboot the machine upon fatal boot issues
+    "console=ttyS0" # enable serial console
+    "console=tty1"
+  ];
+  boot.kernel.sysctl."vm.overcommit_memory" = "1";
+
+  environment.systemPackages = with pkgs; [
+    cryptsetup
+    btrfs-progs
+  ];
+  environment.variables.GC_INITIAL_HEAP_SIZE = "1M";
+
+  networking.useDHCP = true;
+
+  services.openssh = {
+    enable = true;
+    challengeResponseAuthentication = false;
+    passwordAuthentication = false;
+  };
+
+  services.getty.autologinUser = "root";
+  users.users.root.openssh.authorizedKeys.keys = (import ../common/ssh.nix).users;
+}