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https://issues.apache.org/jira/browse/FLINK-11127?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16964210#comment-16964210
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Hwanju Kim commented on FLINK-11127:
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[~tsubasa2oo2], in addition to what [~trohrmann] said (and it's interesting to
me as well why cancel led to metric connection issue), I also wonder what was
the workaround fix you used before 1.8 and had worked fine in the same scenario
without the error you mentioned above. The problematic error related to DNS
would show akka error with "Name or service not known". We've tested for
TM-to-RM registration but not necessarily have seen the metrics connection
error that you showed.
> Make metrics query service establish connection to JobManager
> -------------------------------------------------------------
>
> Key: FLINK-11127
> URL: https://issues.apache.org/jira/browse/FLINK-11127
> Project: Flink
> Issue Type: Improvement
> Components: Deployment / Kubernetes, Runtime / Coordination, Runtime
> / Metrics
> Affects Versions: 1.7.0
> Reporter: Ufuk Celebi
> Priority: Major
> Labels: pull-request-available
> Time Spent: 10m
> Remaining Estimate: 0h
>
> As part of FLINK-10247, the internal metrics query service has been separated
> into its own actor system. Before this change, the JobManager (JM) queried
> TaskManager (TM) metrics via the TM actor. Now, the JM needs to establish a
> separate connection to the TM metrics query service actor.
> In the context of Kubernetes, this is problematic as the JM will typically
> *not* be able to resolve the TMs by name, resulting in warnings as follows:
> {code}
> 2018-12-11 08:32:33,962 WARN akka.remote.ReliableDeliverySupervisor
> - Association with remote system
> [akka.tcp://flink-metrics@flink-task-manager-64b868487c-x9l4b:39183] has
> failed, address is now gated for [50] ms. Reason: [Association failed with
> [akka.tcp://flink-metrics@flink-task-manager-64b868487c-x9l4b:39183]] Caused
> by: [flink-task-manager-64b868487c-x9l4b: Name does not resolve]
> {code}
> In order to expose the TMs by name in Kubernetes, users require a service
> *for each* TM instance which is not practical.
> This currently results in the web UI not being to display some basic metrics
> about number of sent records. You can reproduce this by following the READMEs
> in {{flink-container/kubernetes}}.
> This worked before, because the JM is typically exposed via a service with a
> known name and the TMs establish the connection to it which the metrics query
> service piggybacked on.
> A potential solution to this might be to let the query service connect to the
> JM similar to how the TMs register.
> I tagged this ticket as an improvement, but in the context of Kubernetes I
> would consider this to be a bug.
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