Disko Images

Create disk image files from NixOS + disko configuration.

This is done by running disko-create, disko-mountand thennixos-install in a VM, where each config.disko.devices.disk is mounted as a qcow2 image.

It heavily relies on qcow2 as to not create too large image files. Compression is optional.

Usage

Add disko-images as a NixOS module (using flakes):

# flake.nix
{
  inputs = {
    nixpkgs.url = "nixpkgs/nixos-22.11";
    disko = {
      url = "github:nix-community/disko";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    disko-images.url = "github:chrillefkr/disko-images";
  };
  outputs = { self, nixpkgs, disko, disko-images, ... } @inputs:
  let
    pkgs = import nixpkgs {
      system = "x86_64-linux";
      config.allowUnfree = true;
    };
  in
  {
    nixosConfigurations.my-machine = nixpkgs.lib.nixosSystem {
      inherit pkgs;
      specialArgs.inputs = inputs;
      modules = [
        ./configuration.nix
        ./disko.nix
        disko.nixosModules.disko
        disko-images.nixosModules.disko-images
      ];
    };
  };
}

Build disko images using nix build '.#nixosConfigurations.my-machine.config.system.build.diskoImages'.

Your disk image files appear at ./results/*.qcow2.

About

First of all, this is a very simple (but working) way of creating disk images from NixOS + disko configuration. I've used it mainly to create Raspberry Pi SD card images.

Inspired by:

• https://github.com/NixOS/nixpkgs/blob/master/nixos/modules/installer/sd-card/sd-image-aarch64.nix
• https://nixos.wiki/wiki/NixOps/Virtualization

TODO

• [ ] Ensure support for
  • [X] zfs
  • [ ] btrfs
  • [ ] lvm
• [ ] Individual disk size (config.diskoImages.diskAllocSizes)
• [ ] Create tests
• [ ] Create examples

Known issues

Raspberry Pi Linux kernel

The Raspberry Pi 4 Linux kernel (pkgs.linuxPackages_rpi4) (and problably kernels for the older boards) doesn't seem to work, as the kernel seems to lack support for 9pnet_virtio. It gives me the error message 9pnet_virtio: no channels available for device <device> when it attemts to mount the nix store.

A fix is to use official Linux kernel, e.g.: boot.kernelPackages = pkgs.linuxPackages;

Contribution

Please help. I'm quite new to Nix and NixOS, so any PR or issue is appreciated.