Netboot

Building and serving a netboot image

Example

This example uses Pixiecore for hosting, which works in an ordinary network environment with an existing DHCP server.

Create file system.nix:

let
  # NixOS 22.11 as of 2023-01-12
  nixpkgs = builtins.getFlake "github:nixos/nixpkgs/54644f409ab471e87014bb305eac8c50190bcf48";

  sys = nixpkgs.lib.nixosSystem {
    system = "x86_64-linux";

    modules = [
      pixiecoreNetboot
      ({ config, pkgs, lib, ... }: with lib; {
        config = {
          ## Some useful options for setting up a new system
          # services.getty.autologinUser = mkForce "root";
          # users.users.root.openssh.authorizedKeys.keys = [ ... ];
          # console.keyMap = "de";
          # hardware.video.hidpi.enable = true;

          system.stateVersion = config.system.nixos.release;
        };
      })
    ];
  };

  pixiecoreNetboot = { config, pkgs, lib, modulesPath, ... }: {
    imports = [
      (modulesPath + "/installer/netboot/netboot-minimal.nix")
    ];

    system.build.run-pixiecore = let
      build = config.system.build;
    in
      pkgs.writers.writeBash "run-pixiecore" ''
        exec ${lib.getExe pkgs.pixiecore} \
          boot ${build.kernel}/bzImage ${build.netbootRamdisk}/initrd \
          --cmdline "init=${build.toplevel}/init loglevel=4" \
          --debug --dhcp-no-bind \
          --port 64172 --status-port 64172 "$@"
       '';
  };
in
  sys.config.system.build.run-pixiecore

Run pixiecore:

# Build pixiecore runner
nix build -f system.nix -o /tmp/run-pixiecore

# Open required firewall ports
sudo iptables -I nixos-fw -p udp -m multiport --dports 67,69,4011 -j ACCEPT
sudo iptables -I nixos-fw -p tcp -m tcp --dport 64172 -j ACCEPT

# Run pixiecore
sudo $(realpath /tmp/run-pixiecore)

# Close ports
sudo iptables -D nixos-fw -p udp -m multiport --dports 67,69,4011 -j ACCEPT
sudo iptables -D nixos-fw -p tcp -m tcp --dport 64172 -j ACCEPT

See also

NixOS: Pixiecore module.

NixOS manual: PXE booting.

netboot.xyz

There is now official netboot.xyz support. Just select NixOS from Linux installs and you should be ready to go.

Note: Your iPXE must be recent enough to support https:// links