[ClusterLabs] Request for comments: Deprecating five cluster properties

[Reid Wahl]

We're considering deprecating, and eventually dropping, five cluster
properties. Does anyone object? If you find any of these useful, I'd
love to hear how you're using them and why.

cluster-ipc-limit:
This actually has no effect since ae3b5dc. Prior to that, it affected
only pacemaker-based.

--

enable-startup-probes:
Setting this property to false is dangerous in that it prevents
Pacemaker from gaining an accurate view of resource state, without
preventing other actions as (for example) maintenance mode would do.

You can disable probes using a location constraint rule with
resource-discovery=never instead.

This option was introduced by commit b20fd76, and the expressed
motivation was that the "calculation [of startup probes] is a major
bottleneck for very large clusters." I doubt that's a major concern on
modern hardware, and even if it is, Pacemaker still should have a
correct view of resource state.

--

stop-removed-resources (formerly stop-orphaned-resources):
This property was introduced in 2006 by commit ea1359b, with no
motivation or use case given. It defaults to true. It seems like a bad
idea for Pacemaker to continue running resources that are not part of
its configuration.

--

cancel-removed-actions (formerly stop-removed-actions and
stop-orphaned-actions):
This property was introduced in 2006 by commit ea1359b, with no
motivation or use case given. It defaults to true. It seems like a bad
idea for Pacemaker to continue running actions that are not part of
its configuration.

--

stop-all-resources:
This property was introduced in 2008 by commit 0d6945b, with no
motivation or use case given.

On rare occasions, I have found it convenient for troubleshooting
purposes. However, it can be achieved by a location constraint with
rsc-pattern=".*" and a rule matching all nodes. It can also be
achieved by placing all nodes in standby mode. It seems unlikely to be
very useful to anyone besides developers.

Dropping this property would simplify output messages and the set of
overlapping, possibly conflicting options that control where resources
are allowed to run. (Precedence has to be determined when options
conflict, and such a choice will always be somewhat arbitrary.)

If you're using pcs, you can stop all resources by putting all nodes
in standby: `pcs node standby --all`. That's how I do it in practice.
I presume crmsh has a similar functionality.

-- 
Regards,

Reid Wahl (He/Him)
Senior Software Engineer, Red Hat
RHEL High Availability - Pacemaker