Prerequisites for Configuring NameNode Automatic Failover
Make sure you have a working Zookeeper service and you shut down your HA cluster before you try to configure and deploy automatic failover.
Complete the following prerequisites:
Make sure that you have a working ZooKeeper service. If you have an Ambari-deployed HDP cluster with ZooKeeper, you can use that.Note
In a typical deployment, ZooKeeper daemons are configured to run on three or five nodes. It is however acceptable to co-locate the ZooKeeper nodes on the same hardware as the HDFS NameNode and Standby Node. Many operators choose to deploy the third ZooKeeper process on the same node as the YARN ResourceManager. To achieve performance and improve isolation, Hortonworks recommends configuring the ZooKeeper nodes such that the ZooKeeper data and HDFS metadata is stored on separate disk drives.
Shut down your HA cluster (configured for manual failover).
Currently, you cannot transition from a manual failover setup to an automatic failover setup while the cluster is running.