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https://issues.apache.org/jira/browse/FLINK-21309?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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jiguodai updated FLINK-21309:
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Comment: was deleted
(was: [~chesnay]If so, "randomJobNameSuffix" will be a must-option instead of
be optional when somebody wanna use jobName as filter condition in PromQL. The
solution is confusing and we have no choice but to use regular expressions to
find metrics with exact jobName, which will degrade the speed of data retrieval
in prometheus.
What about invoking callback function to delete metrics in pushgateway when JVM
stops or flink jobs are canceled? We can define a optional configuration in
flink-conf.yaml to support deleting metrics using jobName)
> Metrics of JobManager and TaskManager overwrite each other in pushgateway
> -------------------------------------------------------------------------
>
> Key: FLINK-21309
> URL: https://issues.apache.org/jira/browse/FLINK-21309
> Project: Flink
> Issue Type: Bug
> Components: Runtime / Metrics
> Affects Versions: 1.9.0, 1.10.0, 1.11.0
> Environment: 1. Components :
> Flink 1.9.0/1.10.0/1.11.0 + Prometheus + Pushgateway + Yarn
> 2. Metrics Configuration in flink-conf.yaml :
> {code:java}
> metrics.reporter.promgateway.class:
> org.apache.flink.metrics.prometheus.PrometheusPushGatewayReporter
> metrics.reporter.promgateway.jobName: myjob
> metrics.reporter.promgateway.randomJobNameSuffix: false{code}
>
> Reporter: jiguodai
> Priority: Major
> Attachments: image-2021-02-05-21-07-42-292.png
>
> Original Estimate: 12h
> Remaining Estimate: 12h
>
> When a flink job run on yarn, metrics of jobmanager and taskmanagers will
> overwrite each other. The phenomenon is that on one second you can find only
> jobmanager metrics on pushgateway web ui, while on the next second you can
> find only taskmanager metrics on pushgateway web ui, these two kinds of
> metrics appear alternately. One metric of taskmanager on grafana will be like
> below intermittently (this taskmanager metric disappear on grafana when
> jobmanager metrics overwrite taskmanager metrics):
> !image-2021-02-05-21-07-42-292.png!
> The real reason is that Flink PrometheusPushGatewayReporter use PUT style
> instead of POST style to push metrics to pushgateway, what's more,
> taskmanagers and jobmanager use the same jobName (the only grouping key)
> which we configured in flink-conf.yaml.
> Althought REST URLs are same as below,
> {code:java}
> /metrics/job/<JOB_NAME>{/<LABEL_NAME>/<LABEL_VALUE>}
> {code}
> PUT and POST caused different results, as we can see below :
> * PUT is used to push a group of metrics. All metrics with the grouping key
> specified in the URL are replaced by the metrics pushed with PUT.
> * POST works exactly like the PUT method but only metrics with the same name
> as the newly pushed metrics are replaced.
> For these reasons, it's better to use POST style to push metrics to
> pushgateway to prevent jobmanager metrics and taskmanager metrics from
> overwriting each other, so that we can get continuous graph on grafana. Maybe
> you will say that we can set
> {code:java}
> metrics.reporter.promgateway.randomJobNameSuffix: true{code}
> in flink-conf.yaml, in this way, jobName from different nodes will has a
> random suffix and metrics will not overwrite each other any more. While we
> should be aware that most of users tend to use jobName as filter condition in
> PromQL, and using regular expressions to find exact jobName will degrade the
> speed of data retrieval in prometheus.
> Everytime some body ask why metrics on grafana is discontinuous on Flink
> mailing list, i will tell him that you should change the style of pushing
> metrics to pushgateway from PUT to POST and then repackage the
> flink-metrics-prometheus module. So, why don't we solve the problem
> permanently now ? I hope to have the chance to solve the problem, sincerely.
> related links :
> [https://github.com/prometheus/pushgateway#put-method]
> [https://github.com/prometheus/pushgateway/issues/308]
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