server-configs/shared/modules/state.nix

{ config, lib, ... }:

with lib;

let
  sources = import ./../sources/sources.nix;
in {
  options.mine.state.enable = mkOption {
    type = types.bool;
    default = false;
  };

  imports = [
    (sources.impermanence + "/nixos.nix")
  ];

  config = mkIf config.mine.state.enable {
    environment.persistence = {
      root = {
        persistentStoragePath = "/state/root";

        files = [
          "/etc/machine-id"
        ];

        directories = [
          "/var/lib/nixos"
          "/var/log"
        ];
      };
    };

    # fixes the following error, when trying to use impermanence
    # in `/var/lib/private`, which is needed for DynamicUser.
    # Error: Directory "/var/lib/private" already exists, but has mode 0755 that is too permissive (0700 was requested), refusing.
    systemd.tmpfiles.rules = [
        "d /var/lib/private 0700 root root - -"
    ];
  };
}