We have a 2 node cluster (centos-a / centos-b). During on of your failover tests, we noticed that when we rebooted centos-b, sometimes "duplicate" node entries can be seen in the cluster.
We rebooted centos-b and when it came back online the cluster NiFi saw 2 out of 3 nodes connected. centos-b was added twice (using different nodeIds). 1. centos-b : 05/19/2017 06:48:51 UTC : Node disconnected from cluster due to Have not received a heartbeat from node in 44 seconds 2. centos-b : 05/19/2017 07:42:54 UTC : Received first heartbeat from connecting node. Node connected. Is this by design ? In this case (and I assume in most cases), an address / apiPort combo should uniquely identify a particular node. Why does it get assigned a new nodeId ? As a result, we need to manually disconnected the duplicate disconnected centos-b Output of the cluster rest endpoint : { "cluster": { "nodes": [ { "nodeId": "62be0e80-306a-4037-80e5-b4def5fbc78e", "address": "centos-b", "apiPort": 8080, "status": "DISCONNECTED", "roles": [], "events": [ { "timestamp": "05/19/2017 06:48:51 UTC", "category": "WARNING", "message": "Node disconnected from cluster due to Have not received a heartbeat from node in 44 seconds" }, { "timestamp": "05/18/2017 13:33:56 UTC", "category": "INFO", "message": "Node Status changed from CONNECTING to CONNECTED" } ] }, { "nodeId": "d41d71f2-0ab4-4d6e-bbf2-793bd4faad06", "address": "centos-a", "apiPort": 8080, "status": "CONNECTED", "heartbeat": "05/19/2017 07:44:39 UTC", "roles": [ "Primary Node", "Cluster Coordinator" ], "activeThreadCount": 0, "queued": "0 / 0 bytes", "events": [ { "timestamp": "05/18/2017 13:33:56 UTC", "category": "INFO", "message": "Node Status changed from CONNECTING to CONNECTED" } ], "nodeStartTime": "05/18/2017 13:33:51 UTC" }, { "nodeId": "ddd371c7-2618-4079-8c61-ee30245d15cc", "address": "centos-b", "apiPort": 8080, "status": "CONNECTED", "heartbeat": "05/19/2017 07:44:36 UTC", "roles": [], "activeThreadCount": 0, "queued": "0 / 0 bytes", "events": [ { "timestamp": "05/19/2017 07:42:54 UTC", "category": "INFO", "message": "Received first heartbeat from connecting node. Node connected." }, { "timestamp": "05/19/2017 07:42:47 UTC", "category": "INFO", "message": "Connection requested from existing node. Setting status to connecting." } ], "nodeStartTime": "05/19/2017 07:42:40 UTC" } ], "generated": "07:44:39 UTC" } } -- View this message in context: http://apache-nifi-users-list.2361937.n4.nabble.com/Nifi-clusters-duplicate-nodes-shown-in-cluster-overview-tp1966.html Sent from the Apache NiFi Users List mailing list archive at Nabble.com.