On 2012-12-04T14:48:50, David Vossel <dvos...@redhat.com> wrote:
> The resource ordered set with the 'restart-origin' option gets us half way
> there in the constraint definition. We still have to build the colocation
> set between the vm and the resources so everything runs on the same node
> (perhaps I just assumed that was necessary, correct me if I am wrong)
Right, we end up with two resource sets.
(Unless we allow the "restart-origin" to be set for the order
constraints that are implicit if a colocation resource set is used with
sequential=true. Ouch.)
> The above is "usable", but it requires the user to explicitly set up
> and manage multiple constraint definitions. It seems to me like we
> will eventually want to simplify this process. When that time comes,
> I just want to make sure we approach building the simplified
> abstraction at the configuration level and have the management tools
> (crm/pcs) be a transparent extension of whatever we come up with.
For what it is worth, I'd agree with this; the fact that the most common
constraints are order *AND* colocation and we don't have a
(link|chain|join) statement that adequately provides that has been
annoying me for a while. ;-) I massively appreciate that we do have the
separate dimensions, and people use that - but still, the combination of
both is extremely common.
The independent order + colocation statements do allow for that though;
and in theory, a frontend *could* detect that there's both "A first,
then B" and "B where A is" with the same priority and present it merged
as:
join id-494 inf: A B
Regards,
Lars
--
Architect Storage/HA
SUSE LINUX Products GmbH, GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer, HRB
21284 (AG Nürnberg)
"Experience is the name everyone gives to their mistakes." -- Oscar Wilde
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