andir / bootspec

bootspec

This repository is a research project that aims to improve the bootloader story in NixOS.

Crates

bootspec

The bootspec crate provides various structures and constants useful for interacting with the NixOS boot specification.

synthesize

The synthesize crate provides a CLI that, when provided a path to a NixOS generation and an output file location, will synthesize a boot specification document from the available information.

generator

The generator crate provides a CLI that, when provided a list of NixOS profile generations, will generate bootloader configuration for those generations to a bootloader-specific output directory.

At the moment, only systemd-boot is supported.

installer

The installer crate provides a CLI that will consume the directory created by the generator and install the configuration to the boot device.

At the moment, only systemd-boot is supported.

Usage

NOTE: Please note that only systemd-boot is supported at this time.

In order to take this repository for a test drive, you must use a Nixpkgs that carries our related patches (please see our boot-spec-unstable branch on our Nixpkgs fork for a list of these commits).

Flakes

Use our Nixpkgs branch, add bootspec as an input, and add our module to your configuration:

# flake.nix
{
  inputs.nixpkgs.url = "github:DeterminateSystems/nixpkgs/boot-spec-unstable";
  inputs.bootspec = {
    url = "github:DeterminateSystems/bootspec/main";
    inputs.nixpkgs.follows = "nixpkgs";
  };

  outputs = { self, nixpkgs, bootspec }: {
    nixosConfigurations.nixos = nixpkgs.lib.nixosSystem {
      system = "x86_64-linux";
      modules = [
        bootspec.nixosModules.bootspec
        ./configuration.nix
      ];
    };
  };
}

Without Flakes

Use our fork of Nixpkgs's boot-spec-unstable branch: https://github.com/DeterminateSystems/nixpkgs/tree/boot-spec-unstable.

For example:

$ export "NIX_PATH=nixpkgs=https://github.com/DeterminateSystems/nixpkgs/archive/refs/heads/boot-spec-unstable.tar.gz:$NIX_PATH"

Then create a bootspec.nix file which contains:

let
  bootspecSrc = builtins.fetchGit {
    url = "https://github.com/DeterminateSystems/bootspec.git";
    ref = "main";
  };
in
{
  imports = [ "${bootspecSrc}/nixos-module.nix" ];
  nixpkgs.overlays = [
    (final: prev: {
      bootspec = import bootspecSrc;
    })
  ];
}

Then add the bootspec.nix to your NixOS system's configuration.nix.

Then run nixos-rebuild switch.

Using Secure Boot

NOTE: Secure Boot functionality is in its early stages, and as such some things may or may not work as you might expect.

To use Secure Boot, you will need to import the NixOS module as documented above, as well as set a few configuration options:

{
  boot.loader.secureboot = {
    enable = true;
    signingKeyPath = "/path/to/the/signing/key";
    signingCertPath = "/path/to/the/signing/cert";
  };
}

The Arch Wiki has a good resource on how to generate these keys yourself, which can be found at https://wiki.archlinux.org/title/Unified_Extensible_Firmware_Interface/Secure_Boot#Manual_process. The signing key and cert configured above are the db.key and db.crt mentioned in that resource, but the name doesn't matter. You will need to enroll the generated PK.cer, KEK.cer, and db.cer as the PK (or Platform Key), KEK (or Key Exchange Key), and DB (or Signature Database key). At this point, you should be able to boot using Secure Boot.

License

MIT