Thanks for the help! Before I break out my editor and start writing custom resource agents, one question: Is there a way to use a cloned ocf:pacemaker:attribute resource to set a clone-specific attribute on a node? I.e. attribute "started-0=1" and "started-1=1", depending on the clone ID? For this I would need e.g. a rule to configure a clone specific resource parameter, or is there something like variable substitution in resource parameters?
> On 16. Oct 2024, at 16:22, Ken Gaillot <kgail...@redhat.com> wrote: > > On Mon, 2024-10-14 at 18:49 +0200, Jochen wrote: >> Hi, I have two cloned resources in my cluster that have the following >> properties: >> >> * There are a maximum of two instances of R1 in the cluster, with a >> maximum of two per node >> * When any instance of R1 is started on a node, exactly one instance >> of R2 should run on that node >> >> When I configure this, and verify the configuration with "crm_verify >> -LV", I get the following error: >> >> clone_rsc_colocation_rh) error: Cannot interleave R2-clone and >> R1-clone because they do not support the same number of instances per >> node >> >> How can I make this work? Any help would be greatly appreciated. > > Hi, > > I believe the number of instances has to be the same because each > instance pair on a single node is interleaved. > > There's no direct way to configure what you want, but it might be > possible with a custom OCF agent for R1 and attribute-based rules. > > On start, the R1 agent could set a custom node attribute to some value. > On stop, it could check whether any other instances are active > (assuming that's possible), and if not, clear the attribute. Then, R2 > could have a location rule enabling it only on nodes where the > attribute has the desired value. > > R2 wouldn't stop until *after* the last instance of R1 stops, which > could be a problem depending on the particulars of the service. There > might also be a race condition if two instances are stopping at the > same time, so it might be worthwhile to set ordered=true on the clone. > >> >> >> Current configuration is as follows: >> >> <resources> >> <clone id="R1-clone"> >> <meta_attributes id="R1-clone-meta_attributes"> >> <nvpair name="interleave" value="true" id="R1-clone- >> meta_attributes-interleave"/> >> <nvpair name="resource-stickiness" value="0" id="R1-clone- >> meta_attributes-resource-stickiness"/> >> <nvpair name="clone-max" value="2" id="R1-clone- >> meta_attributes-clone-max"/> >> <nvpair name="clone-node-max" value="2" id="R1-clone- >> meta_attributes-clone-node-max"/> >> <nvpair name="globally-unique" value="true" id="R1-clone- >> meta_attributes-globally-unique"/> >> <nvpair name="failure-timeout" value="300" id="R1-clone- >> meta_attributes-failure-timeout"/> >> <nvpair name="migration-threshold" value="0" id="R1-clone- >> meta_attributes-migration-threshold"/> >> <nvpair id="R1-clone-meta_attributes-target-role" name="target- >> role" value="Stopped"/> >> </meta_attributes> >> </clone> >> <clone id="R2-clone"> >> <meta_attributes id="R2-clone-meta_attributes"> >> <nvpair name="interleave" value="true" id="R2-clone- >> meta_attributes-interleave"/> >> <nvpair name="resource-stickiness" value="0" id="R2-clone- >> meta_attributes-resource-stickiness"/> >> <nvpair name="failure-timeout" value="300" id="R2-clone- >> meta_attributes-failure-timeout"/> >> <nvpair name="migration-threshold" value="0" id="R2-clone- >> meta_attributes-migration-threshold"/> >> <nvpair id="R2-clone-meta_attributes-target-role" name="target- >> role" value="Stopped"/> >> </meta_attributes> >> </clone> >> </resources> >> >> <constraints> >> <rsc_order id="R1-order" kind="Mandatory" first="R1-clone" >> then="R2-clone"/> >> <rsc_colocation id="R2-clone-colocation" score="INFINITY" rsc="R2- >> clone" with-rsc="R1-clone"/> >> </constraints> >> >> > -- > Ken Gaillot <kgail...@redhat.com <mailto:kgail...@redhat.com>> > > _______________________________________________ > Manage your subscription: > https://lists.clusterlabs.org/mailman/listinfo/users > > ClusterLabs home: https://www.clusterlabs.org/
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