[HDFS-3723] All commands should support meaningful --help

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.0-alpha
• Fix Version/s: 2.0.2-alpha
• Component/s: scripts, tools
• Target Version/s: 2.0.2-alpha
• Hadoop Flags: Reviewed
• Assignee: Jing Zhao
• Reporter: Eric Sammer
• Created: 25/Jul/12 16:32
• Updated: 12/May/17 03:33
• Resolved: 15/Aug/12 00:06

Description

Some (sub)commands support -help or -h options for detailed help while others do not. Ideally, all commands should support meaningful help that works regardless of current state or configuration.

For example, hdfs zkfc --help (or -h or -help) is not very useful. Option checking should occur before state / configuration checking.

[esammer@hadoop-fed01 ~]# hdfs zkfc --help
Exception in thread "main" org.apache.hadoop.HadoopIllegalArgumentException: HA is not enabled for this namenode.
        at org.apache.hadoop.hdfs.tools.DFSZKFailoverController.setConf(DFSZKFailoverController.java:122)
        at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:66)
        at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:84)
        at org.apache.hadoop.hdfs.tools.DFSZKFailoverController.main(DFSZKFailoverController.java:168)

This would go a long way toward better usability for ops staff.

Issue Links

• is related to: HDFS-11806 hdfs journalnode command should support meaningful --help