[Linux-HA] Parallel execution of RAs

[Andrew Beekhof]

On 3/8/07, Pavol Gono <palo.gono at gmail.com> wrote:
> Hi
>
> I was long time in belief, that all executions of a resource agent
> with unique instance parameters are serialized. And that there is no
> way to have two such agents (processes) running at the same time.
> (I am not talking about RAs, which are serving different instances of
> resources - here parallelism is logical)
>
> But tests show that during periodic executions for monitoring reasons,
> there can suddenly come stop request. The RA with stop parameter is
> executed even when RA with monitor parameter is running. After some
> time RA with monitor parameter is killed with SIGKILL.
>
> Could you add to documents (e.g. to
> http://www.linux-ha.org/ResourceAgent) the big fat warning, that
> parallel execution of RAs is possible and also killing of RAs before
> timeout is also possible?

LRM actions for any given resource are serialized
if you are seeing the LRM running two actions for the same resource in
parallel then you should log a bug and mark it critical - because
thats really bad

> I designed my RA in bad way because of this :(
>
> My questions are:
> Is there another possibility of parallelism? E.g. start&monitor,
> start&stop, start&start, stop&stop, monitor&monitor? The last case is
> maybe normal when timeout>interval.
> Is there another possibility to have RA killed, before
> timeout/default-action-timeout expires?
>
> Thanks
> Palo
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