[ClusterLabs] Antw: [EXT] Coming in Pacemaker 2.1.3: multiple‑active=stop_unexpected

[Ulrich Windl]

>>> Ken Gaillot <kgaillot at redhat.com> schrieb am 08.04.2022 um 19:16 in
Nachricht
<4a554b35dabcffa792e03802b48f6b7b29849e24.camel at redhat.com>:
> Hi all,
> 
> I'm hoping to have the first release candidate for Pacemaker 2.1.3
> available in a couple of weeks.
> 
> One of the new features will be a new possible value for the "multiple‑
> active" resource meta‑attribute, which specifies how the cluster should
> react if multiple instances of a resource are detected to be active
> when only one should be.
> 
> The default behavior, "restart", stops all the instances and then
> starts one instance where it should be. This is the safest approach
> since some services become disrupted when multiple copies are started.
> 
> However if the user is confident that only the extra copies need to be
> stopped, they can now set multiple‑active to "stop_unexpected". The
> instance that is active where it is supposed to be will not be stopped,
> but all other instances will be.

I tend to suggest an additional value like "wait-for-monitor" which causes the
probe result to be ignored, but see what the next regular monitoring result
is.
In some cases a "monitor" will resolve the virtual conflict. If it's still
there, it could revert to "stop_unexpected".

> 
> If any resources are ordered after the multiply active resource, those
> other resources will still need to be fully restarted. This is because
> any ordering constraint "start A then start B" implies "stop B then
> stop A", so we can't stop the wrongly active instances of A until B is
> stopped.
> ‑‑ 
> Ken Gaillot <kgaillot at redhat.com>
> 
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