[ClusterLabs] Antw: [EXT] Re: Coming in Pacemaker 2.0.5: better start-up/shutdown coordination with sbd

[Ulrich Windl]

>>> Vladislav Bogdanov <bubble at hoster-ok.com> schrieb am 21.08.2020 um 20:55
in
Nachricht <f16f1c7717b388fcd1445b74340c1372719c2d7e.camel at hoster-ok.com>:
> Hi,
> 
> btw, is sbd is now able to handle cib diffs internally?
> Last time I tried to use it with frequently changing CIB, it became a
> CPU hog - it requested full CIB copy on every change.

Hi!

I also wonder whether sbd is a tool to fence hosts, or a node-quorum maker
that controls the cluster.
I think the cluster should control sbd, not the other way 'round.

Regards,
Ulrich

> 
> 
> Fri, 21/08/2020 в 13:16 -0500, Ken Gaillot wrote:
>> Hi all,
>> 
>> Looking ahead to the Pacemaker 2.0.5 release expected toward the end of
>> this year, we will have improvements of interest to anyone running
>> clusters with sbd.
>> 
>> Previously at start-up, if sbd was blocked from contacting Pacemaker's
>> CIB in a way that looked like pacemaker wasn't running (SELinux being a
>> good example), pacemaker would run resources without protection from
>> sbd. Now, if sbd is running, pacemaker will wait until sbd contacts it
>> before it will start any resources, so the cluster is protected in this
>> situation.
>> 
>> Additionally, sbd will now periodically contact the main pacemaker
>> daemon for a status report. Currently, this is just an immediate
>> response, but it ensures that the main pacemaker daemon is responsive
>> to IPC requests. This is a bit more assurance that pacemaker is not
>> only running, but functioning properly. In future versions, we will
>> have even more in-depth health checks as part of this feature.
>> 
>> Previously at shutdown, sbd determined a clean pacemaker shutdown by
>> checking whether any resources were running at shutdown. This would
>> lead to sbd fencing if pacemaker shut down in maintenance mode with
>> resources active. Now, sbd will determine clean shutdowns as part of
>> the status report described above, avoiding that situation.
>> 
>> These behaviors will be controlled by a new option in
>> /etc/sysconfig/sbd or /etc/default/sbd, SBD_SYNC_RESOURCE_STARTUP. This
>> defaults to "no" for backward compatibility when a newer sbd is used
>> with an older pacemaker or vice versa. Distributions may change the
>> value to "yes" since they can ensure both sbd and pacemaker versions
>> support it; users who build their own installations can set it
>> themselves if both versions support it.