Additional HDFS haadmin commands to administer the cluster

After your HA NameNodes are configured and started, you will have access to some additional commands to administer your HA HDFS cluster.

The following are high-level uses of some important subcommands. For specific usage information of each subcommand, you should run hdfs haadmin -help <command>.


Determine whether the given NameNode is active or standby

Connect to the provided NameNode to determine its current state, printing either "standby" or "active" to STDOUT as appropriate. This subcommand might be used by cron jobs or monitoring scripts which need to behave differently based on whether the NameNode is currently active or standby.


Check the health of the given NameNode

Connect to the provided NameNode to check its health. The NameNode is capable of performing some diagnostics on itself, including checking if internal services are running as expected. This command will return 0 if the NameNode is healthy, non-zero otherwise. One might use this command for monitoring purposes.