HA configuration is backward compatible and works with your existing single NameNode configuration. The following instructions describe how to set up NameName HA on a manually-installed cluster. If you installed with Ambari and manage HDP on Ambari 2.0.0 or later, instead of the manual instructions use the Ambari documentation for the NameNode HA wizard.
![[Note]](../common/images/admon/note.png) | Note |
|---|---|
HA cannot accept HDFS cluster names that include an underscore (_). |
To deploy a NameNode HA cluster, use the steps in the following subsections.
