Hi Shadi,
The Cluster will be running high availability with one active NameNode and within a cluster we have no trouble executing commands against an HA NameNode using the NameServiceID.
When we are accessing the cluster from external client application, it should be handled by the client application.
The approach will be like below,
· Get the primary and secondary NameNode IP from user.
· Check the NameNode active state periodically and update primary IP.
· If primary NameNode is failed, then check the secondary NameNode IP status.
· Change the hostname if secondary IP is active and continue the operations.
Please refer the below Web HDFS sample with high availability cluster connection support.
Thanks,
Aravindraja T