thrall: Extract timezone configuration

hosts/thrall/default.nix

@@ -3,15 +3,14 @@
 # and in the NixOS manual (accessible by running ‘nixos-help’).
 
 { config, pkgs, ... }:
-let
-  extIface = "ens3";
-  ledgerVHost = "ledger.failco.de";
+let ledgerVHost = "ledger.failco.de";
 in {
   imports = [
     ./hardware-configuration.nix
     ../../modules/upgrade-pg-cluster.nix
     ../../modules/nix-config.nix
     ../../modules/iohk.nix
+    ../../modules/timezone.nix
   ];
 
   # Use the GRUB 2 boot loader.
@@ -23,9 +22,6 @@ in {
   boot.loader.grub.device = "/dev/vda"; # or "nodev" for efi only
   # boot.loader.systemd-boot.enable = true;
 
-  # Set your time zone.
-  time.timeZone = "Europe/Berlin";
-
   age.secrets = {
     mailPass.file = ../../secrets/mailPass.age;
     paperless-mail.file = ../../secrets/paperless-mail.age;
@@ -41,7 +37,8 @@ in {
   # The global useDHCP flag is deprecated, therefore explicitly set to false here.
   # Per-interface useDHCP will be mandatory in the future, so this generated config
   # replicates the default behaviour.
-  networking = {
+  networking = let extIface = "ens3";
+  in {
     hostName = "thrall";
     domain = "failco.de";
     wireless.enable = false;

modules/timezone.nix

@@ -0,0 +1,5 @@
+{ config, lib, pkgs, ... }:
+
+{
+  time.timeZone = lib.mkDefault "Europe/Berlin";
+}