[HBASE-20943] Add offline/online region count into metrics

• Type: Improvement
• Status: Patch Available
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 2.0.0, 1.2.6.1
• Component/s: metrics
• Assignee: jinghan xu
• Reporter: Tianying Chang
• Created: 25/Jul/18 23:59
• Updated: 23/Aug/18 09:34

Description

We intensively use metrics to monitor the health of our HBase production cluster. We have seen some regions of a table stuck and cannot be brought online due to AWS issue which cause some log file corrupted. It will be good if we can catch this early. Although WebUI has this information, it is not useful for automated monitoring. By adding this metric, we can easily monitor them with our monitoring system.