On Sun, Sep 11, 2011 at 2:30 AM, Vadym Chepkov <vchep...@gmail.com> wrote: > > 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.
If the outside[1] world can't reach the cluster, is there much benefit in having it running? [1] Substitute "outside" for wherever your users are, hopefully you picked a ping node from the same area. > > 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 > _______________________________________________ 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
