question Re: Format ZKFC(hdfs zkfc –formatZK ) in Kerberos environment in Support Questions

How to Run hdfs zkfc -formatZK in a Kerberos-Enabled Hadoop Cluster

dhirajk — Tue, 30 Jun 2026 16:14:09 GMT

To reset ZKFC we have to stop both the ZKFC processes and run the following command as the hdfs super user : hdfs zkfc –formatZK

Is this same for Kerberos enabled environment?

Do we need to stop all HDFS Services and failover control?

Where do we need to run this command in NN or anywhere?

HDP Version - 2.4.3

Thanks in advance.

Re: Format ZKFC(hdfs zkfc –formatZK ) in Kerberos environment

bandarusridhar1 — Fri, 20 Oct 2017 01:37:40 GMT

@Dhiraj

Yes, it will be the same for even Kerberos environment and you need to have valid hdfs keytab before running the command.

Execute the following command on NN1:

hdfs zkfc -formatZK

This command creates a znode in ZooKeeper. The automatic failover system stores uses this znode for data storage.

Try this in lower environments before trying in prod.

Whats the reason to format znode?

Re: Format ZKFC(hdfs zkfc –formatZK ) in Kerberos environment

dhirajk — Fri, 20 Oct 2017 03:10:45 GMT

Reason for format ZKFC is, Adding service rpc port property in NN: Please look for service rpc port in below link.

https://community.hortonworks.com/articles/43838/scaling-the-hdfs-namenode-part-1.html

Re: Format ZKFC(hdfs zkfc –formatZK ) in Kerberos environment

bandarusridhar1 — Fri, 20 Oct 2017 08:21:04 GMT

@Dhiraj

I hope your just changing the ports here. Already rpc calls should be enabled on the cluster. If thats the case "Changing the service RPC port settings requires a restart of the NameNodes, DataNodes and ZooKeeper Failover Controllers to take full effect. If you have NameNode HA setup, you can restart the NameNodes one at a time followed by a rolling restart of the remaining components to avoid cluster downtime."

Hope this helps you.