Selected reference clock is not visible?

[grinapo]

I am not that familar with ntpd-rs to tell whether it's not even using a selected/preferred clock, and that this is the reason that there is no "selected clock indicator" in ntp-ctl status ; or there is a reference clock selection but it's not marked, shown or logged.

If it's an used function would be nice to see the selection result and its changes, in status as well as in the exported metrics, and possibly even in the logs. If not, disregard this issue (but maybe then it would justify a few words in the readme why it isn't working the way we got used to using ntpd classic).

[rnijveld]

One thing to note is that ntpd-rs doesn't just select a single source, but uses information from multiple sources at the same time, and combining that information into steering the clock. This makes it very hard to pinpoint a specific source as being 'the selected reference clock'. But we do have some filtering: we only select agreeing sources for extracting information from. What we could do is show you which sources were selected in that step the last time we ran clock synchronization, but it would only provide limited information probably.

[grinapo]

I think it would provide a rather valuable real-time (and real life) measurement of the usability of the individual sources. On chrony I had some upstreams not selected as sync source in the last year, they have no point to be configured at all. (Probably correlates to other metrics like jitter, but this feels like more practical.)

(And I retrieve them through prometheus metrics, so if you would implement it it would be great if they would be available there as well.)