Re: [chrony-users] is there a retry after "no selectable sources"?

Thanks for the pointers, Miroslav! It does seem like the PTP device is being removed re-created based on the symptoms so far.

Here's a stack trace in case it gives any clues on how I could workaround this: https://gist.github.com/peacepenguin/f5f101d5baa090ab4eebc28d904cc47c#file-gistfile1-txt

In that strace interesting times are at lines:

1: started chronyd via strace, syncs up and runs for awhile just fine

~400: On the host performed sleep--waited 70 seconds--resume

414 : no selectable sources

420: running with no selectable sources, not able to sync up in this state

473: exited chrony, then restarted it, syncs up after that point

Then here's the debug output from another VM on the same host during the sleep/resume cycle, this VM is the same config and has the same problem:

benjamin@home-keycloak:~$ sudo chronyd -d -d
2019-08-12T23:37:26Z chronyd version 3.2 starting (+CMDMON +NTP +REFCLOCK +RTC +PRIVDROP +SCFILTER +SECHASH +SIGND +ASYNCDNS +IPV6 -DEBUG)
2019-08-12T23:37:26Z Setting filter length for PHC0 to 2
2019-08-12T23:37:26Z Frequency -0.462 +/- 1.024 ppm read from /var/lib/chrony/chrony.drift
2019-08-12T23:37:31Z Selected source PHC0
2019-08-12T23:40:27Z Can't synchronise: no selectable sources
^C2019-08-12T23:40:44Z chronyd exiting
benjamin@home-keycloak:~$ date
Mon Aug 12 17:40:51 MDT 2019
benjamin@home-keycloak:~$ sudo chronyd -d -d
2019-08-12T23:41:19Z chronyd version 3.2 starting (+CMDMON +NTP +REFCLOCK +RTC +PRIVDROP +SCFILTER +SECHASH +SIGND +ASYNCDNS +IPV6 -DEBUG)
2019-08-12T23:41:19Z Setting filter length for PHC0 to 2
2019-08-12T23:41:19Z Frequency 0.372 +/- 1.148 ppm read from /var/lib/chrony/chrony.drift
2019-08-12T23:41:24Z Selected source PHC0
2019-08-12T23:41:24Z System clock wrong by 71.153229 seconds, adjustment started
2019-08-12T23:42:36Z System clock was stepped by 71.153229 seconds

Thanks for any help!

-Ben

On Mon, Aug 12, 2019 at 1:23 AM Miroslav Lichvar <mlichvar@xxxxxxxxxx> wrote:

On Fri, Aug 09, 2019 at 12:14:09PM -0600, Benjamin DeCamp wrote:
> It appears that once Chrony has decided that there are no selectable
> sources, chrony goes silent and doesn't seem to retry those sources. Log
> entry: "Can't synchronise: no selectable sources".
>
> How can I force Chrony to regularly re-check for a selectable source? or is
> there a configuration item to control re-checking the selectable sources?

chronyd is polling the refclock constantly and when it starts
providing measurements, if it will be selected again. If that doesn't
happen in your case, it's probably something wrong with the PTP device
that happens in the suspend/resume cycle. Maybe it was removed and a
new one was created? That would require a restart of chronyd.

It might help if we could see the debug output (chronyd -d -d) and
maybe also a strace.

--
Miroslav Lichvar

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