[Pacemaker] Question about master/slave resource promotion

[Florian Haas]

On Sun, Feb 26, 2012 at 1:08 AM, David Vossel <dvossel at redhat.com> wrote:
> ----- Original Message -----
>> From: "Florian Haas" <florian at hastexo.com>
>> Yeah, actually using a resource type that is capable of running in
>> master/slave mode would be a good start. :) Use
>> ocf:pacemaker:Stateful
>> instead of ocf:pacemaker:Dummy in your test setup.
>>
>
> The example works with the Stateful resource agent, and your comment helped me understand how this concept works better. I was not aware resource agents knew anything about master/slave status.  For some reason I had it in my head the master/slave concept was just internal to Pacemaker and we could make whatever we wanted out of it.

If a resource management feature had no bearing on the resources at
all, being just "internal" to the resource manager, what would be the
point of having the feature in the first place?

Any resource that you want to manage as part of a master/slave set
obviously has to support the promote and demote operations. Those that
don't (such as Dummy, for example) have no way of ever getting
promoted.

The following items in the documentation should provide additional insight:

http://www.clusterlabs.org/doc/en-US/Pacemaker/1.1/html/Pacemaker_Explained/ch10s03s09.html
http://www.linux-ha.org/doc/dev-guides/_literal_promote_literal_action.html
http://www.linux-ha.org/doc/dev-guides/_literal_demote_literal_action.html

Cheers,
Florian

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