nix-config/modules/boot/loader.org

Bootloaders and Filesystems

• Bootloaders and Filesystems
  • Bootloaders
  • ZFS

Bootloaders and Filesystems

This page sets up the bootloader of my machines. Whilst I generally prefer to use systemd-boot, some of my VPS use GRUB, and some use ZFS. All that gets exposed with my module nixos.loader.

{
  flake.modules.nixos.loader = {
    lib,
    config,
    ...
  }:
    with lib; let
      cfg = config.mySystem.boot;
    in {

    };
}

Bootloaders

By default, I want to use systemd-boot on my machines, but I need it to be disabled whenever I use something else. For now, this “something else” is only GRUB, but I’m not excluding using something else on yet another machine such as rEFInd. To ensure a single source of truth regarding whether systemd-boot is to be used, I have an option for that.

options.mySystem.boot.systemd-boot = mkOption {
  type = types.bool;
  default = !cfg.grub.enable;
  description = "Does the system use systemd-boot?";
};

I can now set some options depending on that, such as whether to enable systemd-boot itself (duh), and whether the installation process can touch my EFI variables.

config.boot.loader = {
  systemd-boot.enable = cfg.systemd-boot;
  efi.canTouchEfiVariables = cfg.systemd-boot;
};

But, I have a VPS that requires me to use GRUB. For this, I also have an option to enable it.

options.mySystem.boot.grub = {
  enable = mkEnableOption "Does the system use GRUB? (Disables systemd-boot)";
  device = mkOption {
    type = types.path;
    description = "The GRUB device";
    default = "";
  };
};

I can no pass these options to the boot configuration of my machine.

config.boot.loader.grub = mkIf cfg.grub.enable {
  inherit (cfg.grub) enable device;
};

ZFS

Now, this is where I enable