[Pacemaker] Order Constraint for: stop rscA only when rscB is running ?

[Andrew Beekhof]

On Thu, Oct 2, 2008 at 10:23, Andreas Kurz <andreas.kurz at linbit.com> wrote:
> Hi,
>
> I have a Heartbeat 2.1.3 two-node cluster and I wonder if there is a way to
> create constraints that work like that:
>
> * Two resources (rscA and rscB) of class "heartbeat" that should run together
> on one node .... simple advisory colocation constraint
>
> <rsc_colocation id="rscA-colocated-with-rscB"
>        from="rscA" to="rscB"
>        score="1" symmetrical="true"/>
>
> * When doing maintenance on one node I put the node into standby mode and want
> rscA only stop and migrate away if rscB is already up and running on the
> other node and vice versa because  there must always run at least one of
> these resources in the cluster.
>
> I added two order_constraints and tested it with ptest on an adapted live cib
> but they seem to produce a loop:

This is logical if you draw it out (and remember that Stop X always
precedes Start X)

Any reason not to just use the following?

<rsc_order id="always-start-A-after-B"
       from="service_rscB" action="start"
       type="before"
       to="service_rscA" to_action="start"
       symmetrical="true" score="0"/>

>
> <rsc_order id="stop-rscA-only-after-rscB-start"
>        from="service_rscA" action="stop"
>        type="after"
>        to="service_rscB" to_action="start"
>        symmetrical="false" score="0"/>
>
> <rsc_order id="stop-rscB-only-after-rscA-start"
>        from="service_rscB" action="stop"
>        type="after"
>        to="service_rscA" to_action="start"
>        symmetrical="false" score="0"/>
>
> Is there a way to get the requested behavior or is a manual resource after
> resource migration the only way to achieve this?
>
> Regards,
> Andreas
>
> --
> : Andreas Kurz
> : LINBIT | Your Way to High Availability
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> :
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