title: How to resolve ERROR: epmd error for host nxdomain (non-existing domain)?
body: <p>I am trying to setup RabbitMQ Operator and RabbitMQ Cluster  on K8S cluster on bare metal using this <a href="https://www.rabbitmq.com/kubernetes/operator/using-operator.html#create" rel="nofollow noreferrer">link</a></p>
  <p>K8S Cluster has got 1 master and 1 worker node</p>
  <p>RabbitMQ Cluster pod log</p>
  <p>[root@re-ctrl01 containers]# kubectl logs definition-server-0 -n rabbitmq-system</p>
  <pre><code>BOOT FAILED  (Tailored output)
  ===========
  ERROR: epmd error for host definition-server-0.definition-nodes.rabbitmq-system: nxdomain (non-existing domain)
  
  11:51:13.733 [error] Supervisor rabbit_prelaunch_sup had child prelaunch started with rabbit_prelaunch:run_prelaunch_first_phase() at undefined exit with reason {epmd_error,&quot;definition-server-0.definition-nodes.rabbitmq-system&quot;,nxdomain} in context start_error.  Crash dump is being written to: erl_crash.dump...
  </code></pre>
  <p>[root@re-ctrl01 containers]# kubectl describe pod definition-server-0 -n rabbitmq-system</p>
  <pre><code>Name:         definition-server-0
  Namespace:    rabbitmq-system
  Priority:     0
  Events:
    Type     Reason     Age               From               Message
    ----     ------     ----              ----               -------
    Normal   Scheduled  44s               default-scheduler  Successfully assigned rabbitmq-system/definition-server-0 to re-ctrl01.local
    Normal   Pulled     43s               kubelet            Container image &quot;rabbitmq:3.8.16-management&quot; already present on machine
    Normal   Created    43s               kubelet            Created container setup-container
    Normal   Started    43s               kubelet            Started container setup-container
    Normal   Pulled     42s               kubelet            Container image &quot;rabbitmq:3.8.16-management&quot; already present on machine
    Normal   Created    42s               kubelet            Created container rabbitmq
    Normal   Started    42s               kubelet            Started container rabbitmq
    Warning  Unhealthy  4s (x3 over 24s)  kubelet            Readiness probe failed: dial tcp 10.244.0.xxx:5672: connect: connection refused
  </code></pre>
  <p>I added the following entries to <code>/etc/hosts</code> file of <code>worker node</code> because I am NOT sure whether the entry has to be added to <code>master or worker</code></p>
  <pre><code>[root@re-worker01 ~]# cat /etc/hosts
  127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
  127.0.0.1   re-worker01.local re-worker01 definition-server-0.definition-nodes.rabbitmq-system
  </code></pre>
  <p>I am stuck with this issue for almost 2 days.  I googled and found similar issues but none resolved my issue</p>
  <p>I see multiple issues in pod logs and describe output and I am unable to find out the root cause</p>
  <ol>
  <li>Where can I find <code>erl_crash.dump</code>  file on K8S ?</li>
  <li>Is this really a hostname related issue ?</li>
  <li>10.244.0.xxx:5672: connect: connection refused  - Is this issue is because of <code>'epmd'</code> or something else ?</li>
  </ol>