On 5.5.2017 08:15, Ulrich Windl wrote:
Jan Wrona <[email protected]> schrieb am 04.05.2017 um 16:41 in Nachricht<[email protected]>:I hope I'll be able to explain the problem clearly and correctly.My setup (simplified): I have two cloned resources, a filesystem mount and a process which writes to that filesystem. The filesystem is Gluster so its OK to clone it. I also have a mandatory ordering constraint "start gluster-mount-clone then start writer-process-clone". I don't have a STONITH device, so I've disable STONITH by settin||||g stonith-enabled=false. The problem: Sometimes the Gluster freezes for a while, which causes the gluster-mount resource's monitor with the OCF_CHECK_LEVEL=20 to timeout (it is unable to write the status file). When this happens, the clusterActually I would do two things: 1) Find out why Gluster freezes, and what to do to avoid that
It freezes when one of the underlying MD RAIDs starts its regular check. I've decreased its speed limit (from the default 200 MB/s to the 50 MB/s, I cannot go any lower), but it helped only a little, the mount still tends to freeze for a few seconds during the check.
2) Implement stonith
Currently I can't. But AFAIK Pacemaker should work properly even with disabled STONITH and the state I've run into doesn't seem right to me at all. I was asking for clarification of what the cluster is trying to do in such situation, I don't understand the "Ignoring expired calculated failure" log messages and I don't understand why the crm_mon was showing that the writer-process is started even though it was not.
Regards, Ulrichtries to recover by restarting the writer-process resource. But the writer-process is writing to the frozen filesystem which makes it uninterruptable, not even SIGKILL works. Then the stop operation times out and on-fail with disabled STONITH defaults to block (don’t perform any further operations on the resource): warning: Forcing writer-process-clone away from node1.example.org after 1000000 failures (max=1000000) After that, the cluster continues with the recovery process by restarting the gluster-mount resource on that node and it usually succeeds. As a consequence of that remount, the uninterruptable system call in the writer process fails, signals are finally delivered and the writer-process is terminated. But the cluster doesn't know about that! I thought I can solve this by setting the failure-timeout meta attribute to the writer-process resource, but it only made things worse. The documentation states: "Stop failures are slightly different and crucial. ... If a resource fails to stop and STONITH is not enabled, then the cluster has no way to continue and will not try to start the resource elsewhere, but will try to stop it again after the failure timeout.", but I'm seeing something different. When the policy engine is launched after the nearest cluster-recheck-interval, following lines are written to the syslog: crmd[11852]: notice: State transition S_IDLE -> S_POLICY_ENGINE pengine[11851]: notice: Clearing expired failcount for writer-process:1 on node1.example.org pengine[11851]: notice: Clearing expired failcount for writer-process:1 on node1.example.org pengine[11851]: notice: Ignoring expired calculated failure writer-process_stop_0 (rc=1, magic=2:1;64:557:0:2169780b-ca1f-483e-ad42-118b7c7c1a7d) on node1.example.org pengine[11851]: notice: Clearing expired failcount for writer-process:1 on node1.example.org pengine[11851]: notice: Ignoring expired calculated failure writer-process_stop_0 (rc=1, magic=2:1;64:557:0:2169780b-ca1f-483e-ad42-118b7c7c1a7d) on node1.example.org pengine[11851]: warning: Processing failed op monitor for gluster-mount:1 on node1.example.org: unknown error (1) pengine[11851]: notice: Calculated transition 564, saving inputs in /var/lib/pacemaker/pengine/pe-input-362.bz2 crmd[11852]: notice: Transition 564 (Complete=2, Pending=0, Fired=0, Skipped=0, Incomplete=0, Source=/var/lib/pacemaker/pengine/pe-input-362.bz2): Complete crmd[11852]: notice: State transition S_TRANSITION_ENGINE -> S_IDLE crmd[11852]: notice: State transition S_IDLE -> S_POLICY_ENGINE crmd[11852]: warning: No reason to expect node 3 to be down crmd[11852]: warning: No reason to expect node 1 to be down crmd[11852]: warning: No reason to expect node 1 to be down crmd[11852]: warning: No reason to expect node 3 to be down pengine[11851]: warning: Processing failed op stop for writer-process:1 on node1.example.org: unknown error (1) pengine[11851]: warning: Processing failed op monitor for gluster-mount:1 on node1.example.org: unknown error (1) pengine[11851]: warning: Forcing writer-process-clone away from node1.example.org after 1000000 failures (max=1000000) pengine[11851]: warning: Forcing writer-process-clone away from node1.example.org after 1000000 failures (max=1000000) pengine[11851]: warning: Forcing writer-process-clone away from node1.example.org after 1000000 failures (max=1000000) pengine[11851]: notice: Calculated transition 565, saving inputs in /var/lib/pacemaker/pengine/pe-input-363.bz2 pengine[11851]: notice: Ignoring expired calculated failure writer-process_stop_0 (rc=1, magic=2:1;64:557:0:2169780b-ca1f-483e-ad42-118b7c7c1a7d) on node1.example.org pengine[11851]: warning: Processing failed op monitor for gluster-mount:1 on node1.example.org: unknown error (1) crmd[11852]: notice: Transition 566 (Complete=0, Pending=0, Fired=0, Skipped=0, Incomplete=0, Source=/var/lib/pacemaker/pengine/pe-input-364.bz2): Complete crmd[11852]: notice: State transition S_TRANSITION_ENGINE -> S_IDLE pengine[11851]: notice: Calculated transition 566, saving inputs in /var/lib/pacemaker/pengine/pe-input-364.bz2 Then after each cluster-recheck-interval: crmd[11852]: notice: State transition S_IDLE -> S_POLICY_ENGINE pengine[11851]: notice: Ignoring expired calculated failure writer-process_stop_0 (rc=1, magic=2:1;64:557:0:2169780b-ca1f-483e-ad42-118b7c7c1a7d) on node1.example.org pengine[11851]: warning: Processing failed op monitor for gluster-mount:1 on node1.example.org: unknown error (1) crmd[11852]: notice: Transition 567 (Complete=0, Pending=0, Fired=0, Skipped=0, Incomplete=0, Source=/var/lib/pacemaker/pengine/pe-input-364.bz2): Complete crmd[11852]: notice: State transition S_TRANSITION_ENGINE -> S_IDLE And the crm_mon is happily showing the writer-process as Started, although it is not running. This is very confusing. Could anyone please explain what is going on here? ||||_______________________________________________ Users mailing list: [email protected] http://lists.clusterlabs.org/mailman/listinfo/users 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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_______________________________________________ Users mailing list: [email protected] http://lists.clusterlabs.org/mailman/listinfo/users Project Home: http://www.clusterlabs.org Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf Bugs: http://bugs.clusterlabs.org
