From 78d8e2ca119e4019415006ac5ea553e62c8e70c4 Mon Sep 17 00:00:00 2001
From: Florian Klink <flokli@flokli.de>
Date: Mon, 18 Mar 2024 17:20:05 +0200
Subject: [PATCH] nixos/timesyncd: further document services.timesyncd.servers

Running systemd-timesyncd with an empty list of timeservers to sync from
does not work.

In case an empty list is configured here, systemd will fall back to its
compiled-in defaults, which NixOS sets to `{0..4}.nixos.pool.ntp.org`,
as per https://github.com/systemd/systemd/blob/main/docs/DISTRO_PORTING.md#ntp-pool

This has caused some confusion. Explicitly document this, and describe
how to disable timesyncd.
---
 nixos/modules/system/boot/timesyncd.nix | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/nixos/modules/system/boot/timesyncd.nix b/nixos/modules/system/boot/timesyncd.nix
index 2666e4cd6b28..ef17c1481abb 100644
--- a/nixos/modules/system/boot/timesyncd.nix
+++ b/nixos/modules/system/boot/timesyncd.nix
@@ -21,6 +21,9 @@ with lib;
         type = types.listOf types.str;
         description = lib.mdDoc ''
           The set of NTP servers from which to synchronise.
+          Note if this is set to an empty list, the defaults systemd itself is
+          compiled with ({0..4}.nixos.pool.ntp.org) apply,
+          In case you want to disable timesyncd altogether, use the `enable` option.
         '';
       };
       extraConfig = mkOption {