[ClusterLabs] kind=Optional order constraint not working at startup

Andrei Borzenkov arvidjaar at gmail.com
Thu Sep 22 12:32:09 EDT 2016


22.09.2016 11:19, Auer, Jens пишет:
...
> I think start-up is just a special case of what I think is a dependency for starting a resource. 
> My current understanding is that a mandatory constraint means "If you start/stop resource A then you 
> have to start/stop resource B". An optional  constraint says that the constraint only holds when
> you start/stop two resources together in a single transition. What I want to express is more like
> a dependency "don't start resource A before resource B has been started at all. State changes of resource B 
> should not impact resource A". I realize this is kind of odd, but if A can tolerate outages of its dependency B,
> e.g. reconnect, this makes sense. In principle this is what an optional constraint does, but not restricted
> to a single transition.
> 

But if A can tolerate outage of B, why does it matter whether A is
started before or after B? By the same logic it should be able to
reconnect once B is up? At least that is what I'd expect.




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