HDFS HA

Perform the tasks
  1. Cloudera Manager does not support the comma separated entries. Review dfs.data.transfer.protection and hadoop.rpc.protection parameters. If SSL is not enabled, then click Undo. This will clear the selections.
  2. Start HDFS service.
  3. Format the ZooKeeper Failover controller ZnNode. SSH to the Failover controller host And perform the following using the example:# cd /var/run/cloudera-scm-agent/process/<xx>-hdfs-FAILOVERCONTROLLER /opt/cloudera/parcels/CDH/bin/hdfs --config /var/run/cloudera-scm-agent/process/<xx>-hdfs-FAILOVERCONTROLLER/ zkfc -formatZK
    1. Check the output in the log for success. If the error is: `ERROR tools.DFSZKFailoverController: DFSZKFailOverController exiting due to earlier exception java.io.IOException: Running in secure mode, but config doesn't have a keytab`.
    2. The ZooKeeper nodes are not created. You must manually create the ZNodes for the Failover controllers to start and allow an Active Namenode to be elected.
    3. With the zookeeper-client, open a ZooKeeper Shell `zookeeper-client -server <a_zk_server>`
    4. Create the required ZNodes create /hadoop-ha create /hadoop-ha/<namenode_namespace>.
  4. Start HDFS service again.