[Ci-users] Install & enable NTP on Duffy nodes

Sun Jan 12 12:15:45 UTC 2020
František Šumšal <frantisek at sumsal.cz>

Hello!

After recent struggles with compilation under Vagrant over NFS, I'd like to ask
if it would be possible to automatically sync all machines provided by Duffy using
NTP.

We encountered several nasty race conditions caused by system time discrepancies
between a Duffy host and a VM, which I managed to mitigate by installing & enabling
chrony. Unfortunately, it's not perfect, as the time synchronization apparently takes
some time, so the race condition is present, but it's much less probable.

Going through Jenkins logs it looks that all machines have their time significantly off:

● chronyd.service - NTP client/server
   Loaded: loaded (/usr/lib/systemd/system/chronyd.service; enabled; vendor preset: enabled)
   Active: active (running) since Sun 2020-01-12 16:06:53 GMT; 5h 51min left
     Docs: man:chronyd(8)
           man:chrony.conf(5)
 Main PID: 1992 (chronyd)
   CGroup: /system.slice/chronyd.service
           └─1992 /usr/sbin/chronyd

Jan 12 16:06:53 n15.pufty systemd[1]: Starting NTP client/server...
Jan 12 16:06:53 n15.pufty chronyd[1992]: chronyd version 3.4 starting (+CMDMON +NTP +REFCLOCK +RTC +PRIVDROP +SCFILTER +SIGND +ASYNCDNS +SECHASH +IPV6 +DEBUG)
Jan 12 16:06:53 n15.pufty systemd[1]: Started NTP client/server.
Jan 12 16:07:01 n15.pufty chronyd[1992]: Selected source xx.xx.xx.xx
Jan 12 16:07:01 n15.pufty chronyd[1992]: System clock wrong by -21251.336765 seconds, adjustment started
Jan 12 10:12:50 n15.pufty chronyd[1992]: System clock was stepped by -21251.336765 seconds

I suspect waiting for the synchronization to fully complete using chrony's CLI utilities would
help, but having this to be handled automatically by each machine would be much better.

Thanks!

Frantisek

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