8.5. HDFS Known Issues

BUG-26890: Commands in HA mode behave differently compared to non-HA

Problem: Commands in HA mode behave differently compared to non-HA. For example:

hdfs dfsadmin -safemode enter - if nn2 is active and nn1 is standby, command will run with no errors, but it will set standby to safemode and not active. If nn1 is actually off, the command will try nn2 and the command in effect will do what it needs to do.

The same behavior is true for hdfs dfsadmin -saveNamespace.

Workaround: You can add the fs and specify hdfs://hostname:8020 of the active namenode, for example: hdfs dfsadmin -fs hdfs://<namenodehostactive>:8020 -saveNamespace.