Chapter 9. Configuring RHEL HA for Hadoop 1.x

Ambari supports High Availability of components such as NameNode or JobTracker in a HDP 1.x cluster running RHEL HA. After installing NameNode monitoring components on hosts in an HA cluster, as described in HDP System Administration, configure Ambari to reassign any component on a failover host in the cluster, using the host_relocate_component.py script.

For example, if the host for the primary NameNode or JobTracker component fails, Ambari reassigns the primary NameNode or JobTracker component to the configured failover host, when you start or restart Ambari server.

	Note
	Make sure that NameNode is installed. For successful reassignment, a component must be in one of the following states: Maintenance (started or stopped) Unknown