Bug#964444: systemd-timesyncd: time synchronization suddenly stopped working

[Vincent Lefevre]

On 2020-07-08 01:49:16 +0200, Vincent Lefevre wrote:
> On 2020-07-07 23:59:06 +0200, Michael Biebl wrote:
> > Am 07.07.20 um 12:58 schrieb Vincent Lefevre:
> > > Package: systemd-timesyncd
> > > Version: 245.6-1
> > > Severity: important
> > > 
> > > systemd-timesyncd no longer seems to work. I couldn't find any
> > > reason in the logs. Now there's a 5-second delta!
> > > 
> > > zira:~> timedatectl timesync-status
> > >        Server: (null) (3.debian.pool.ntp.org)   
> > > Poll interval: 34min 8s (min: 32s; max 34min 8s)
> > >          Leap: normal                           
> > >       Version: 4                                
> > >       Stratum: 2                                
> > >     Reference: 596DFB17                         
> > >     Precision: 1us (-24)                        
> > > Root distance: 40.580ms (max: 5s)               
> > >        Offset: -1.087495s                       
> > 
> > For smaller offset likes this one, timesyncd will adjust the time gradually.
> > I don't see anything in the logs which would show that timesyncd is not
> > working.
> 
> I don't know what this offset means, but this does not explain the
> 5-second difference with other machines.

Note that after a reboot yesterday, I can't currently reproduce
the issue.

There's something suspicious in the "timedatectl timesync-status"
output above:

> > >        Server: (null) (3.debian.pool.ntp.org)   

Currerntly I get:

       Server: 193.52.136.2 (0.debian.pool.ntp.org)

So, why "(null)" above instead of the IP address?

It seems that there was a temporary DNS resolution failure, and
after that, systemd-timesyncd stopped doing anything (I think that
the offset was the old difference, but the difference increased
over the hours).

Note also that "systemctl status systemd-timesyncd.service" was
outputting

     Status: "Idle."

which is unusual.

-- 
Vincent Lefèvre <vincent at vinc17.net> - Web: <https://www.vinc17.net/>
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