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https://issues.apache.org/jira/browse/FLINK-4087?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15346459#comment-15346459
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ASF GitHub Bot commented on FLINK-4087:
---------------------------------------
Github user tillrohrmann commented on a diff in the pull request:
https://github.com/apache/flink/pull/2145#discussion_r68238384
--- Diff:
flink-core/src/main/java/org/apache/flink/metrics/reporter/JMXReporter.java ---
@@ -265,4 +329,72 @@ public Object getValue() {
return gauge.getValue();
}
}
+
+ /**
+ * JMX Server implementation that JMX clients can connect to.
+ *
+ * Heavily based on j256 simplejmx project
+ *
+ *
https://github.com/j256/simplejmx/blob/master/src/main/java/com/j256/simplejmx/server/JmxServer.java
+ */
+ private static class JMXServer {
+ private int port;
+ private Registry rmiRegistry;
--- End diff --
Hmm, if we don't understand the code and, thus, cannot explain what it
does, we shouldn't include the code. The question who should maintain this kind
of code. I think it would be best if you could do some research to clarify how
the `JMXServer` works and add some comments explaining the different components.
> JMXReporter can't handle port conflicts
> ---------------------------------------
>
> Key: FLINK-4087
> URL: https://issues.apache.org/jira/browse/FLINK-4087
> Project: Flink
> Issue Type: Improvement
> Components: Metrics
> Affects Versions: 1.1.0
> Reporter: Chesnay Schepler
> Assignee: Chesnay Schepler
> Priority: Blocker
> Fix For: 1.1.0
>
>
> The JMXReporter is currently configured to use a single port that is set as a
> JVM argument.
> This approach has a few disadvantages:
> If multiple TaskManagers run on the same machine only 1 can expose metrics.
> This issue is compounded by the upcoming JobManager metrics, which would then
> prevent TM metrics from being exposed in local setups.
> Currently, we prevent other TM's from exposing metrics by checking the the
> start-daemon-sh whether a TM is already running, and if so clear the
> arguments. This isn't a particular safe way to do it, and this script is not
> used when deploying on yarn, leading to TM failures since the JVM can't
> allocate the JMX port.
> We should find a way to specifiy port-ranges for JMX and log the final port
> used.
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