title: I'm getting data consuming error with Flume Kafka Source in Kubernetes
body: <p>We have a Kafka cluster currently running. An application of ours is retrieving data from a Topic in this Kafka cluster using Flume Kafka Source. Our Kafka Cluster is running on servers. Our Flume application is running on a Docker Container.</p>
  <p>Now we want to migrate our Flume application running on Docker to Kubernetes environment. When we did this, we encountered some errors. We detected that the Flume Kafka Source was unable to retrieve the data.</p>
  <p>Flume logs about errors are as follows. (I replaced some special parts with ...)</p>
  <pre><code>[PollableSourceRunner-KafkaSource-r1] (org.apache.kafka.clients.NetworkClient.processDisconnection:671)  - [Consumer clientId=consumer-1, groupId=test1] Connection to node 1 could not be established. Broker may not be available.
  [PollableSourceRunner-KafkaSource-r1] (org.apache.kafka.clients.consumer.internals.AbstractCoordinator.markCoordinatorUnknown:729)  - [Consumer clientId=consumer-1, groupId=...] Group coordinator ...:9092 (id: ... rack: null) is unavailable or invalid, will attempt rediscovery
  </code></pre>
  <p>Why did we get an error in a Kubernetes environment when we did not encounter any problems while working on Docker?</p>
  <p>Thank you!</p>