{ impermanence, ... }:

{
  imports = [ impermanence.nixosModules.impermanence ];

  environment.persistence."/persistence" = {
    directories = [
      "/nix"
      "/var/lib/nixos"

      # Systemd's state directory.
      # This is for instance where timers activation times are stored, hence
      # why it is desirable for this directory to be persistent.
      "/var/lib/systemd"
    ];

    files = [
      # The machine ID is not supposed to change across reboots. For instance,
      # it's used by journald to filter logs.
      "/etc/machine-id"
    ];
  };

  fileSystems."/persistence" = {
    enable = true;
    neededForBoot = true;
  };
}