[HDFS-3870] QJM: add metrics to JournalNode

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: QuorumJournalManager (HDFS-3077)
• Fix Version/s: QuorumJournalManager (HDFS-3077)
• Target Version/s: QuorumJournalManager (HDFS-3077)
• Hadoop Flags: Reviewed
• Assignee: Todd Lipcon
• Reporter: Todd Lipcon
• Created: 30/Aug/12 02:33
• Updated: 05/Sep/12 04:31
• Resolved: 05/Sep/12 04:31

Description

The JournalNode should expose some basic metrics through the usual interface. In particular:

• the writer epoch, accepted epoch,
• the last written transaction ID and last committed txid (which may be newer in case that it's in the process of catching up)
• latency information for how long the syncs are taking

Please feel free to suggest others that come to mind.