Details
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Improvement
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Status: Resolved
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Major
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Resolution: Fixed
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None
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None
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Reviewed
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Exposed a metric 'LastJournalTimestamp' for JournalNode
Description
If there are three JNs and only one JN is failing to journal, we can detect it by monitoring the difference of the last written transaction id among JNs from NN WebUI or JN metrics. However, it's difficult to define the threshold to alert because the increase rate of the number of transaction depends on how busy the cluster is. Therefore I'd like to propose a metric to expose the timestamp of the last journal. That way we can easily alert if a JN is failing to journal for some fixed period.