netboot.nix

Alternative expressions for netboot.

In the future, I'd like to structure this as a module, to easily turn on recursive Nix builds, or target a ZFS filesystem, etc.

Also, the future should include tests in this repo.

Included Module Expressions

• ./quickly.nix uses recursive Nix to build the initrd and squashfs filesystems more quickly, allowing for faster iteration of images. Initial testing reduced build time from 5-10 minutes per image to 15-30 seconds.

  The ./size-test/build.sh test is able to build an incremental netboot image in just 12 seconds, and the initrd is not rebuilt.

Setting up recursive nix

Setting up recursive Nix requires support on the build machine:

{ pkgs, ... }: {
  nix = {
    package = pkgs.nixUnstable;
    systemFeatures = [ "recursive-nix" "kvm" "nixos-test" ];
    extraOptions = ''
      experimental-features = recursive-nix
    '';
  };
}