Turning safe mode on HA NameNodes

You can use the applicable dfsadmin command options to turn safe mode on for a single or both the active and standby NameNodes.

  • To turn safe mode on for both NameNodes, run hdfs dfsadmin -safemode enter.
  • To turn safe mode on for a single NameNode, run hdfs dfsadmin -fs hdfs://<host>:<port> -safemode enter