On Sep 8, 2011, at 3:40 PM, Florian Haas wrote: >>> On 09/08/11 20:59, Brad Johnson wrote: >>>> We have a 2 node cluster with a single resource. The resource must run >>>> on only a single node at one time. Using the pacemaker:ocf:ping RA we >>>> are pinging a WAN gateway and a LAN host on each node so the resource >>>> runs on the node with the greatest connectivity. The problem is when a >>>> ping host goes down (so both nodes lose connectivity to it), the >>>> resource moves to the other node due to timing differences in how fast >>>> they update the score attribute. The dampening value has no effect, >>>> since it delays both nodes by the same amount. These unnecessary >>>> fail-overs aren't acceptable since they are disruptive to the network >>>> for no reason. >>>> Is there a way to dampen the ping update by different amounts on the >>>> active and passive nodes? Or some other way to configure the cluster to >>>> try to keep the resource where it is during these tie score scenarios? > > location pingd-constraint group_1 \ > rule $id="pingd-constraint-rule" pingd: defined pingd > > May I suggest that you simply change this constraint to > > location pingd-constraint group_1 \ > rule $id="pingd-constraint-rule" \ > -inf: not_defined pingd or pingd lte 0 > > That way, only a host that definitely has _no_ connectivity carries a > -INF score for that resource group. And I believe that is what you > really want, rather than take the actual ping score as a placement > weight (your "best connectivity" approach). > > Just my 2 cents, though. >
Even though this approach was recommended many times, there is a problem with it. What if all nodes for some reason are not able to ping ? This rule would cause a resource to be brought down completely, whereas if you use "best connectivity" approach it will stay up where it was before network failed. Vadym _______________________________________________ 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://developerbugs.linux-foundation.org/enter_bug.cgi?product=Pacemaker
