[ClusterLabs] Opinions wanted: another logfile question for Pacemaker 2.0

[Klaus Wenninger]

On 01/15/2018 05:51 PM, Ken Gaillot wrote:
> Currently, Pacemaker will use the same detail log as corosync if one is
> specified (as "logfile:" in the "logging {...}" section of
> corosync.conf).
>
> The corosync developers think that is a bad idea, and would like
> pacemaker 2.0 to always use its own log.
>
> Corosync and pacemaker both use libqb to write to the logfile. libqb
> doesn't have any locking mechanism, so there could theoretically be
> some conflicting writes, though we don't see any in practice.
>
> Does anyone have a strong opinion on this one way or the other? Do you
> like having pacemaker and corosync detail messages in one logfile, or
> would you prefer separate logfiles?

I'm aware that a log-entry from one source (like corosync) appearing
before an entry from another source (like pacemaker) doesn't necessarily
mean that this correctly reflects their sequence in time but usually
it is working fairly well.
With timestamps of 1 second granularity in 2 files we would be definitely
off worse.
Please correct me if timestamping is configurable already but if not
I would say we should either have at least the possibility to log into
a single file or we should have timestamping with a granularity at
least 3 magnitudes finer. (configurable timestamps as in pacemaker-alerts
might be a solution)

Regards,
Klaus

>
> Note that this question only applies to the detail log; the syslog
> would still get messages from everything (when configured).