[systemd-devel] How to ensure a systemd unit waits for ntpd to sync before starting?

Marc Haber mh+systemd-devel at zugschlus.de
Tue Apr 2 09:58:27 UTC 2019

On Tue, Apr 02, 2019 at 10:17:26AM +0200, Lennart Poettering wrote:
> Well packaged NTP servers should have a separate .service unit that
> waits until an NTP sync is reached. For example, systemd's own
> systemd-timesyncd.service comes with a companion
> systemd-time-wait-sync.service that does this.

systemd-time-wait-sync.service invokes
/lib/systemd/systemd-time-wait-sync do to the actual wait, which is an
ELF binary. While this is a valid approach to do this, an interested
used will now need to download the systemd souces, unpack them, search
for the source for the binary just to find out what this service
actually does.

To adapt it to wait for something else, one needs to whack out a

IMO, this is a classic case of "doing this scripted is way easier and
more flexible". Please consider for the future.


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