Assume we have an ELB cluster with 2 nodes connected to AS and ESB clusters. (Here the well known members are 2 ELBs) All nodes are connected and working fine (members joined the cluster). Let’s say, if both ELBs were down and then restarted, the ASs and ESBs also have to be restarted to join the cluster again. This is a known issue in Hazelcast. If all WK members fail, the entire cluster has to be restarted. Thats why they have recommend to have two WKs members at minimum. To avoid this situation you can configure the AS and ESB management nodes also as well-known members. Clustering details can found on AS[2] and ESB[3] links. [1] https://docs.wso2.com/display/CLUSTER420/Overview [2] https://docs.wso2.com/display/CLUSTER420/Clustering+Application+Server [3] https://docs.wso2.com/display/CLUSTER420/Clustering+ESB To configure AS & ESB mgt nodes as WK members, follow the following steps - Update the AS mgt node axis2.xml file with WK member details as f