HA configuration is backward compatible and works with your existing single NameNode configuration.
![[Note]](../common/images/admon/note.png) | Note |
|---|---|
These instructions provide information on setting up NameNode HA on a manually installed cluster. If you installed with Ambari and manage HDP 2.0 on Ambari 1.4.1 or later, use the Ambari documentation for the NameNode HA wizard instead of these instructions. |
First, enable the NameNodes to share metadata through QJM. Then, enable automatic failover through Zookeeper.
