"hdfs dfsadmin -rollingUpgrade" command was newly added in HDFS-5752, and some other commands and parameters will be added in the future. This issue exists to flag undocumented commands and parameters when HDFS-5535 branch is merging to trunk.
Provide admin commands for data node upgrade
Add a new DFSAdminCommand for rolling upgrade
Add new NN startup options for downgrade and rollback using upgrade marker
Add a new option for starting standby NN when rolling upgrade is in progress