Hi Klaus, On 8/12/19 1:39 PM, Klaus Wenninger wrote: > On 8/9/19 9:06 PM, Yan Gao wrote: >> On 8/9/19 6:40 PM, Andrei Borzenkov wrote: >>> 09.08.2019 16:34, Yan Gao пишет: >>>> Hi, >>>> >>>> With disk-less sbd, it's fine to stop cluster service from the cluster >>>> nodes all at the same time. >>>> >>>> But if to stop the nodes one by one, for example with a 3-node cluster, >>>> after stopping the 2nd node, the only remaining node resets itself with: >>>> >>> That is sort of documented in SBD manual page: >>> >>> --><-- >>> However, while the cluster is in such a degraded state, it can >>> neither successfully fence nor be shutdown cleanly (as taking the >>> cluster below the quorum threshold will immediately cause all remaining >>> nodes to self-fence). >>> --><-- >>> >>> SBD in shared-nothing mode is basically always in such degraded state >>> and cannot tolerate loss of quorum. >> Well, the context here is it loses quorum *expectedly* since the other >> nodes gracefully shut down. >> >>> >>>> Aug 09 14:30:20 opensuse150-1 sbd[1079]: pcmk: debug: >>>> notify_parent: Not notifying parent: state transient (2) >>>> Aug 09 14:30:20 opensuse150-1 sbd[1080]: cluster: debug: >>>> notify_parent: Notifying parent: healthy >>>> Aug 09 14:30:20 opensuse150-1 sbd[1078]: warning: inquisitor_child: >>>> Latency: No liveness for 4 s exceeds threshold of 3 s (healthy servants: 0) >>>> >>>> I can think of the way to manipulate quorum with last_man_standing and >>>> potentially also auto_tie_breaker, not to mention >>>> last_man_standing_window would also be a factor... But is there a better >>>> solution? >>>> >>> Lack of cluster wide shutdown mode was mentioned more than once on this >>> list. I guess the only workaround is to use higher level tools which >>> basically simply try to stop cluster on all nodes at once. It is still >>> susceptible to race condition. >> Gracefully stopping nodes one by one on purpose is still a reasonable >> need though ... > If you do the teardown as e.g. pcs is doing it - first tear down > pacemaker-instances and then corosync/sbd - it is at > least possible to tear down the pacemaker-instances one-by one > without risking a reboot due to quorum-loss. > With kind of current sbd having in > - > https://github.com/ClusterLabs/sbd/commit/824fe834c67fb7bae7feb87607381f9fa8fa2945 > - > https://github.com/ClusterLabs/sbd/commit/79b778debfee5b4ab2d099b2bfc7385f45597f70 > - > https://github.com/ClusterLabs/sbd/commit/a716a8ddd3df615009bcff3bd96dd9ae64cb5f68 > this should be pretty robust although we are still thinking > (probably together with some heartbeat to pacemakerd > that assures pacemakerd is checking liveness of sub-daemons > properly) of having a cleaner way to detect graceful > pacemaker-shutdown. These are all good improvements, thanks!
But in this case the remaining node is not shutting down yet, or it's intentionally not being shut down :-) Loss of quorum is as expected, so is following no-quorum-policy, but self-reset is probably too much? Regards, Yan _______________________________________________ Manage your subscription: https://lists.clusterlabs.org/mailman/listinfo/users ClusterLabs home: https://www.clusterlabs.org/
