Update reconfigurable properties on Hadoop node without restart.
Display reconfigurable properties on namenode.
$ sudo -u hadoop -i hdfs dfsadmin -reconfig namenode namenode.example.org:9000 properties
Node [namenode.example.org:9000] Reconfigurable properties: dfs.heartbeat.interval dfs.namenode.heartbeat.recheck-interval dfs.namenode.replication.max-streams dfs.namenode.replication.max-streams-hard-limit dfs.namenode.replication.work.multiplier.per.iteration dfs.storage.policy.satisfier.mode fs.protected.directories hadoop.caller.context.enabled ipc.9000.backoff.enable
Display reconfigurable properties on datanode.
$ sudo -u hadoop -i hdfs dfsadmin -reconfig datanode datanode3.example.org:9867 properties
Node [datanode3.example.org:9867] Reconfigurable properties: dfs.datanode.data.dir dfs.datanode.balance.max.concurrent.moves
Reconfigure datanode after configuration update.
$ sudo -u hadoop -i hdfs dfsadmin -reconfig datanode datanode3.example.org:9867 start
Started reconfiguration task on node [datanode3.example.org:9867].
Inspect changes.
$ sudo -u hadoop -i hdfs dfsadmin -reconfig datanode datanode3.example.org:9867 status
Reconfiguring status for node [datanode3.example.org:9867]: started at Tue Jul 20 18:41:06 UTC 2021 and finished at Tue Jul 20 18:41:06 UTC 2021. SUCCESS: Changed property dfs.datanode.data.dir From: "/opt/hadoop/local_data/datanode" To: "/opt/hadoop/local_data/datanode,/opt/hadoop/local_data/disk2,/opt/hadoop/local_data/disk3"