[HDFS-8551] Fix hdfs datanode CLI usage message

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.6.0
• Fix Version/s: 2.8.0, 3.0.0-alpha1
• Hadoop Flags: Reviewed
• Assignee: Brahma Reddy Battula
• Reporter: Xiaoyu Yao
• Created: 06/Jun/15 06:06
• Updated: 30/Aug/16 01:33
• Resolved: 16/Jun/15 21:21

Description

There are two issues with current "hdfs datanode" usage message below.

Usage: java DataNode [-regular | -rollback]
    -regular                 : Normal DataNode startup (default).
    -rollback                : Rollback a standard or rolling upgrade.
  Refer to HDFS documentation for the difference between standard
  and rolling upgrades.

1. "java DataNode" should be "hdfs datanode"
2. "rollingupgrace" option is missing but it is document correctly in the link.

Usage: hdfs datanode [-regular | -rollback | -rollingupgrace rollback]

COMMAND_OPTION	Description
-regular	Normal datanode startup (default).
-rollback	Rollback the datanode to the previous version. This should be used after stopping the datanode and distributing the old hadoop version.
-rollingupgrade rollback	Rollback a rolling upgrade operation.