Leaving SafeMode :
Failover NameNode :$ bin/hadoop dfsadmin -safemode leave
find HDFS option
dfs.namenode.http-address.mycluster.nn1=nn.example.com:50070
dfs.namenode.http-address.mycluster.nn2=dn1.example.com:50070
So nn.example.com is nn1
[root@nn ~]# hdfs haadmin -getServiceState nn1
standby
Force transition for a NN to Active
[root@nn ~]# hdfs haadmin -transitionToActive --forcemanual nn1