NiFi UnknowHostException in Cluster

[#1]

Our group is experiencing issues in our Dev cluster (5 servers). The attached error has started kicking users out of the UI and we are having trouble identifying the underlying issue. Any help is appreciated.

Symptoms:

Server is working fine. After a couple hours this error ("javax.ws.rs.ProcessingException: java.net.UnknownHostException: (Hostname)") starts kicking users out of the webUI.

Thanks

[#2]

@Zack Atkinson

Make sure that every node in your NiFi Cluster can resolve the hostnames for every other node in your NiFi cluster.

Make sure that all NiFi nodes can resolve and reach the configured zookeeper servers.

Make sure the following properties are set and their are no typos (including leading or trailing whitespaces) in the nifi.properties file:

nifi.zookeeper.connect.string <-- should be set to resolvable hostnames for zookeeper servers

nifi.web.https.host or nifi.web.http.host <-- should be set to resolvable hostname for server

nifi.cluster.is.node <-- should be set to resolvable hostname for server

What is seen in the nifi-app.log around timeframe issue occurs? Is there a full stack trace with this error?

Thanks,

Matt