In HDFS, following roles are supported in NameNodeRole: ACTIVE, BACKUP, CHECKPOINT and STANDBY.
Active and Standby are the state of the NameNode. While Backup and CheckPoint are the name/role of the daemons that are started. This mixes up the run time state of NameNode with the daemon role. I propose changing the NameNodeRole to: NAMENODE, BACKUP, CHECKPOINT.
HDFS-1974 will introduce the states active and standby to the daemon that is running in the role NAMENODE.