@Sampath Kumar : It looks like namenode is not installed on one of the hosts configured for namenode HA. Check both the hosts where you are trying to configure nn1 and nn2, and install the namenode on the host where it is not installed. curl -u <ambari_user>:<ambari_password> -H "X-Requested-By:ambari" -i -X POST http://<ambari-port>:<ambari-port>/api/v1/clusters/<cluster_name>/hosts/<host_name>/host_components/NAMENODE ... View more