[
https://issues.apache.org/jira/browse/HDFS-17055?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17738642#comment-17738642
]
ASF GitHub Bot commented on HDFS-17055:
---------------------------------------
xinglin commented on PR #5790:
URL: https://github.com/apache/hadoop/pull/5790#issuecomment-1613505813
Hi @goiri ,
Could you help commit this PR into branch-3.3? It is the same change which
you helped merge into trunk this Monday. This PR contains only one code-change
commit and the rest are empty commits to trigger multiple builds. We have one
clean build and that should be good enough to merge. If you have different
thoughts, please let me know. thanks,
> Export HAState as a metric from Namenode for monitoring
> -------------------------------------------------------
>
> Key: HDFS-17055
> URL: https://issues.apache.org/jira/browse/HDFS-17055
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs
> Affects Versions: 3.4.0, 3.3.9
> Reporter: Xing Lin
> Assignee: Xing Lin
> Priority: Minor
> Labels: pull-request-available
> Fix For: 3.4.0
>
>
> We'd like measure the uptime for Namenodes: percentage of time when we have
> the active/standby/observer node available (up and running). We could monitor
> the namenode from an external service, such as ZKFC. But that would require
> the external service to be available 100% itself. And when this third-party
> external monitoring service is down, we won't have info on whether our
> Namenodes are still up.
> We propose to take a different approach: we will emit Namenode state directly
> from namenode itself. Whenever we miss a data point for this metric, we
> consider the corresponding namenode to be down/not available. In other words,
> we assume the metric collection/monitoring infrastructure to be 100% reliable.
> One implementation detail: in hadoop, we have the _NameNodeMetrics_ class,
> which is currently used to emit all metrics for {_}NameNode.java{_}. However,
> we don't think that is a good place to emit NameNode HAState. HAState is
> stored in NameNode.java and we should directly emit it from NameNode.java.
> Otherwise, we basically duplicate this info in two classes and we would have
> to keep them in sync. Besides, _NameNodeMetrics_ class does not have a
> reference to the _NameNode_ object which it belongs to. An _NameNodeMetrics_
> is created by a _static_ function _initMetrics()_ in {_}NameNode.java{_}.
> We shouldn't emit HA state from FSNameSystem.java either, as it is
> initialized from NameNode.java and all state transitions are implemented in
> NameNode.java.
>
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
---------------------------------------------------------------------
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
