nixos/profiles: add image-based-appliance profile

# This profile sets up a sytem for image based appliance usage. An appliance is

# installed as an image, cannot be re-built, has no Nix available, and is

# generally not meant for interactive use. Updates to such an appliance are

# handled by updating whole partition images via a tool like systemd-sysupdate.

{ lib, modulesPath, ... }:

{

  # Appliances are always "minimal".

  imports = [

    "${modulesPath}/profiles/minimal.nix"

  ];

  # The system cannot be rebuilt.

  nix.enable = false;

  system.switch.enable = false;

  # The system is static.

  users.mutableUsers = false;

  # The system avoids interpreters as much as possible to reduce its attack

  # surface.

  boot.initrd.systemd.enable = lib.mkDefault true;

  networking.useNetworkd = lib.mkDefault true;

}