You could reset the current Kafka cluster by deleting the data directories on the filesystem on each node. This is the same as starting up a new and empty Kafka cluster. To do this, delete everything inside Kafka data directory.

Instead of resetting Kafka as described above, you can let use a new set of queues in the existing Kafka cluster. When reusing the same Kafka cluster, must be configured with a new HUMIO_KAFKA_TOPIC_PREFIX to detect the changes.

It's important to note that it will not work to delete and recreate topics with the same names. In that case cannot detect the Kafka switch. If Kafka is managed by (KAFKA_MANAGED_BY_HUMIO), the new topics will be created automatically when starts up. Otherwise you must create topics externally before you start .

Now you're ready to get the Kafka cluster started. Start all Kafka nodes, wait for them to be running and verify the Kafka cluster.

Once Kafka has started, start the nodes. It's important to start one node first. This node will detect the Kafka switch and create a new epoch in .

To verify that the Kafka switch was detected and handled, look for this line in the debug log:

Switching epoch to=${epochKey} from=${latestEpoch.kafkaClusterId}
- I'm the first cluster member to get here
  for this kafka. newEpoch=${newEpoch}

When the first node is up and running and the above logline confirms a new epoch has been created, the rest of the nodes can be started.

At that point, the cluster should be running again. Check the cluster nodes in the administrative section of the user interface: http://$HUMIOHOST/system/administration/partitions/ingest