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
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.