>>> shivraj dongawe <shivraj...@gmail.com> schrieb am 14.02.2021 um 12:03 in Nachricht <calpaho--3erfwst70mbl-wm9g6yh3ytd-wda1r_cknbrsxu...@mail.gmail.com>: > We are running a two node cluster on Ubuntu 20.04 LTS. Cluster related > package version details are as > follows: pacemaker/focal-updates,focal-security 2.0.3-3ubuntu4.1 amd64 > pacemaker/focal 2.0.3-3ubuntu3 amd64 > corosync/focal 3.0.3-2ubuntu2 amd64 > pcs/focal 0.10.4-3 all > fence-agents/focal 4.5.2-1 amd64 > gfs2-utils/focal 3.2.0-3 amd64 > dlm-controld/focal 4.0.9-1build1 amd64 > lvm2-lockd/focal 2.03.07-1ubuntu1 amd64 > > Cluster configuration details: > 1. Cluster is having a shared storage mounted through gfs2 filesystem with > the help of dlm and lvmlockd. > 2. Corosync is configured to use knet for transport. > 3. Fencing is configured using fence_scsi on the shared storage which is > being used for gfs2 filesystem > 4. Two main resources configured are cluster/virtual ip and postgresql-12, > postgresql-12 is configured as a systemd resource. > We had done failover testing(rebooting/shutting down of a node, link > failure) of the cluster and had observed that resources were getting > migrated properly on the active node. > > Recently we came across an issue which has occurred repeatedly in span of > two days. > Details are below: > 1. Out of memory killer is getting invoked on active node and it starts > killing processes. > Sample is as follows: > postgres invoked oom-killer: gfp_mask=0x100cca(GFP_HIGHUSER_MOVABLE), > order=0, oom_score_adj=0 > 2. At one instance it started with killing of pacemaker and on another with > postgresql. It does not stop with the killing of a single process it goes > on killing others(more concerning is killing of cluster related processes) > as well. We have observed that swap space on that node is 2 GB against RAM > of 96 GB and are in the process of increasing swap space to see if this > resolves this issue. Postgres is configured with shared_buffers value of 32 > GB(which is way less than 96 GB). > We are not yet sure which process is eating up that much memory suddenly. > 3. As a result of killing processes on node1, node2 is trying to fence > node1 and thereby initiating stopping of cluster resources on node1.
How is fencing being done? > 4. At this point we go in a stage where it is assumed that node1 is down > and application resources, cluster IP and postgresql are being started on > node2. > 5. Postgresql on node 2 fails to start in 60 sec(start operation timeout) > and is declared as failed. During the start operation of postgres, we have > found many messages related to failure of fencing and other resources such > as dlm and vg waiting for fencing to complete. > Details of syslog messages of node2 during this event are attached in file. > 6. After this point we are in a state where node1 and node2 both go in > fenced state and resources are unrecoverable(all resources on both nodes). > > Now my question is out of memory issue of node1 can be taken care by > increasing swap and finding out the process responsible for such huge > memory usage and taking necessary actions to minimize that memory usage, > but the other issue that remains unclear is why cluster is not shifted to > node2 cleanly and become unrecoverable. _______________________________________________ Manage your subscription: https://lists.clusterlabs.org/mailman/listinfo/users ClusterLabs home: https://www.clusterlabs.org/