[HDFS-15821] Add metrics for in-service datanodes

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 3.3.1, 3.4.0, 3.2.3
• Fix Version/s: 3.3.1, 3.4.0, 3.2.3
• Component/s: metrics
• Labels: pull-request-available
• Target Version/s: 3.3.1, 3.4.0, 3.2.3
• Hadoop Flags: Reviewed
• Assignee: Zehao Chen
• Reporter: Zehao Chen
• Created: 04/Feb/21 22:06
• Updated: 11/Feb/24 08:06
• Resolved: 15/Feb/21 20:53

Description

We currently have metrics for live datanodes but some of the datanodes may be in decommissioning state or maintenance state. Adding this metric allows us to know how many nodes are currently in service, where NumInServiceDatanodes = NumLiveDataNodes - NumDecomLiveDataNodes - NumInMaintenanceLiveDataNodes.

Issue Links

• links to: GitHub Pull Request #2690