[Pacemaker] Dependency Trees

Donald Stahl don at blacksun.org
Thu Feb 21 09:40:06 EST 2013


> No.
>
> [quote]
> If you say "colocate A with B" and there is nowhere B is allowed to
> run, then A wont be allowed to run either.
> But once the cluster has figured out where they go, it doesn't stop
> them being started in parallel.
> [/quote]
>
> in this case, A = OraListener1 and B = OraBin1
>
> You only get the "Start A then start B" part by adding the ordering constraint.

I'm not sure I understand where the "sequential" option comes into
play with a colocation set then.

Or to put it another way- I'm not sure what practical difference there
is in these examples:

http://clusterlabs.org/wiki/FAQ#Collocation_Sets

colocation myset inf: app1 app2
colocation myset inf: ( app1 app2 )

The first seems to say that app1 is dependent on app2 being able to
run somewhere.

Does the second one simply say that they must not be split up, but if
only one can run, that's fine?

-Don




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