[HBASE-21320] [canary] Cleanup of usage and add commentary

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.2.0, 2.1.1, 2.0.3
• Component/s: canary
• Hadoop Flags: Reviewed
• Release Note: Cleans up usage and docs around Canary. Does not change command-line args (though we should -- smile).
• Assignee: Michael Stack
• Reporter: Michael Stack
• Created: 16/Oct/18 05:32
• Updated: 17/Oct/18 13:05
• Resolved: 17/Oct/18 05:21

Description

I was trying to us the Canary as a diagnosis tool figuring what was online and what was off but I couldn't make sense of how to use it. There was a bug where we default to regionserver 'mode' always and only way to change it was via a system property and a cryptic class name.

Changed it so we don't specify output ahead of figuring what 'mode' we are to run in. Cleaned-up usage and added commentary. It seems useable now (Did not change command-line args though they need changing).

Issue Links

• links to: Review Board (branch-2.1)