title: Regular network connection failure of a Kafka broker in a 3 broker cluster in OpenShift
body: <p>For reasons unknown and often several times a week in Production and Test, we cannot communicate with a Kafka broker, and this message repeats in the log: WARN Connection to node nnnn could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient) </p>
  
  <p>Strangely this in turn prevents Kafka working (We cannot Produce/Consume).</p>
  
  <p>OpenShift doesn't recognize it's not working, and Kafka doesn't recognize it either.</p>
  
  <p>I am about to add a Livenessprobe to the YAML to restart the Pod if the command in a Broker container is not executed, but we'd like to find the root cause naturally.</p>
  
  <p>If I use the Curl url:hostport command from another Broker or Zookeeper node, you can get a reply from all other Brokers and Zookeepers. Yet Curl to the Kafka node that has "failed" returns "Could not resolve host ...", even though I can go into OpenShift and use the Terminal. I cannot find any other errors in the logs.</p>
  
  <p>I don't know if this is a Kafka or OpenShift/Kubernetes issue.</p>
  
  <p>If anyone else has had this and resolved it, I'd be grateful for some pointers.</p>