Cluster members not able to identify its correct group leader.
Last updated on APRIL 17, 2018
Applies to:Oracle WebLogic Server - Version 10.3.3 and later
Information in this document applies to any platform.
When one of the Cluster member reconnects to the group it is not able to identify its group leader and selects the wrong group leader.
In unicast Clustering, the cluster is divided into smaller manageable groups. Each group has a group leader associated with it. Group members communicate with the group leader and the group leaders communicate within themselves. This can be seen in the Clusters > Monitoring page for Unicast Clusters.
Whenever a server drops out of a cluster, based on the heartbeat messages received after that, it would re-join the cluster.
When re-joining the cluster it would attempt to find its group leader in order to join that particular group.
In this scenario, the server was unable to find its group leader and would randomly select a new group leader, thus creating a new group.
However in the customer's scenario (review Attachment MS4.jsp) we would find that if MS4 dropped out of the cluster and rejoined it, it would select MS2 as the group leader. whereas MS2 would still show MS1 as the group leader. In this scenario, the correct behavior would be MS2 showing MS2 as the group leader for itself, as MS2 itself is a group leader, however that was not happening.
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