On 2013-03-20 04:11, Quentin Smith wrote: > On Wed, 20 Mar 2013, Andreas Kurz wrote: > >> On 2013-03-19 17:02, Quentin Smith wrote: >>> Hi- >>> >>> I have my cluster configured to use a cloned ping resource, such that I >>> can write a constraint that I prefer resources to run on a node that has >>> network connectivity. That works fine if a machine loses its network >>> connection (the ping attribute goes to 0, resources migrate to another >>> machine, etc.). >>> >>> However, if instead what happens is the ping /target/ goes offline, it >>> seems that Pacemaker will bounce resources around the cluster, as each >>> node notices that the ping target is unreachable at a slightly different >>> time. >> >> using more than one targets is always a good idea and choose targets >> that are also highly available > > Sure, and we have. No choice of ping targets is going to help us if the > servers are partitioned from the rest of the network, through.
In that case typically no-one can access the services anyways, then not having resources bouncing around is more a cosmetic issue ... assuming it is not extremely expensive to start/stop them e.g. because of cold caches. > >>> Is there any way to get Pacemaker to delay resource transitions until at >>> least one full polling cycle has happened, so that in the event of an >>> outage of the ping target, resources stay put where they are running? >> >> there is the "dampen" parameter .... use a high value like 3 or more >> times the monitor-interval to give all nodes the chance to detect the >> dead target(s), that should help. > > Does that actually help in this case? My understanding is that the > dampen parameter will delay the attribute change for each host, but > those delays will still tick down separately for each node, resulting in > exactly the same behavior, just delayed by dampen seconds. if the dampen time-out is reached and there was a permanent change of that attribute on one node, all nodes flush their current value ... so yes, that should actually help. Regards, Andreas > > --Quentin > >> >> Regards, >> Andreas >> >> -- >> Need help with Pacemaker? >> http://www.hastexo.com/now >> >>> >>> --Quentin >>> >>> _______________________________________________ >>> Pacemaker mailing list: Pacemaker@oss.clusterlabs.org >>> http://oss.clusterlabs.org/mailman/listinfo/pacemaker >>> >>> Project Home: http://www.clusterlabs.org >>> Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf >>> Bugs: http://bugs.clusterlabs.org >> >> >> >> >> >> _______________________________________________ >> Pacemaker mailing list: Pacemaker@oss.clusterlabs.org >> http://oss.clusterlabs.org/mailman/listinfo/pacemaker >> >> Project Home: http://www.clusterlabs.org >> Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf >> Bugs: http://bugs.clusterlabs.org >> > > _______________________________________________ > Pacemaker mailing list: Pacemaker@oss.clusterlabs.org > http://oss.clusterlabs.org/mailman/listinfo/pacemaker > > Project Home: http://www.clusterlabs.org > Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf > Bugs: http://bugs.clusterlabs.org
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_______________________________________________ Pacemaker mailing list: Pacemaker@oss.clusterlabs.org http://oss.clusterlabs.org/mailman/listinfo/pacemaker Project Home: http://www.clusterlabs.org Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf Bugs: http://bugs.clusterlabs.org
