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https://issues.apache.org/jira/browse/STORM-3501?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Stig Rohde Døssing resolved STORM-3501.
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Fix Version/s: 2.1.0
Resolution: Fixed
Thanks for the fix [~diogopmonteiro]. Applied to master and 2.1.x-branch.
> Local Cluster worker restarts
> -----------------------------
>
> Key: STORM-3501
> URL: https://issues.apache.org/jira/browse/STORM-3501
> Project: Apache Storm
> Issue Type: Bug
> Components: storm-server
> Affects Versions: 2.0.0, 2.1.0
> Environment: Linux
> Reporter: Diogo Monteiro
> Assignee: Diogo Monteiro
> Priority: Minor
> Labels: pull-request-available
> Fix For: 2.1.0
>
> Time Spent: 0.5h
> Remaining Estimate: 0h
>
> I was trying to launch a topology that I'm developing (in 2.0.0) and noticed
> that the worker was getting restarted each ~30 seconds.
> I placed a breakpoint in the _kill_ method of _LocalContainer_
> ([https://github.com/apache/storm/blob/2ba95bbd1c911d4fc6363b1c4b9c4c6d86ac9aae/storm-server/src/main/java/org/apache/storm/daemon/supervisor/LocalContainer.java#L66])
> to try and understand why the worker was getting restarted.
>
> The call stack was:
> _kill:66, LocalContainer (org.apache.storm.daemon.supervisor)
> killContainerFor:269, Slot (org.apache.storm.daemon.supervisor)
> handleRunning:724, Slot (org.apache.storm.daemon.supervisor)
> stateMachineStep:218, Slot (org.apache.storm.daemon.supervisor)
> run:931, Slot (org.apache.storm.daemon.supervisor) _
>
> With this I can understand that the worker is killed because a blob has
> changed
> ([https://github.com/apache/storm/blob/2ba95bbd1c911d4fc6363b1c4b9c4c6d86ac9aae/storm-server/src/main/java/org/apache/storm/daemon/supervisor/Slot.java#L724]).
> In fact, there's a changing blob in the _dynamicState_ at that point.
>
> I checked the _AsyncLocalizer_ which downloads, caches blobs locally, and
> notifies the Slot state machine of a changing blob.
>
> I noticed this:
> *
> [https://github.com/apache/storm/blob/2ba95bbd1c911d4fc6363b1c4b9c4c6d86ac9aae/storm-server/src/main/java/org/apache/storm/localizer/AsyncLocalizer.java#L339]
> *
> [https://github.com/apache/storm/blob/2ba95bbd1c911d4fc6363b1c4b9c4c6d86ac9aae/storm-server/src/main/java/org/apache/storm/localizer/AsyncLocalizer.java#L265]
> *
> [https://github.com/apache/storm/blob/2ba95bbd1c911d4fc6363b1c4b9c4c6d86ac9aae/storm-server/src/main/java/org/apache/storm/localizer/LocallyCachedTopologyBlob.java#L142]
> *
> [https://github.com/apache/storm/blob/2ba95bbd1c911d4fc6363b1c4b9c4c6d86ac9aae/storm-server/src/main/java/org/apache/storm/localizer/LocallyCachedTopologyBlob.java#L192]
>
> Which tell me that (correct me if I'm wrong):
> * Supervisor tries to update blobs each 30 seconds.
> * The topology jar blob requires extraction of the resources directory
> (either from a jar or directly in a classpath URL). It does so in
> _fetchUnzipToTemp_ and it's existence is checked in _isFullyDownloaded_.
> * The Slot is notified of a changing blob if:
> * the remote version is different from the local version (the code has
> changed).
> * OR the blob is not fully downloaded (the jar exists, and the extracted
> resources directory exists).
>
> Well, I did not have a resources folder under the root of the classpath, and
> that's why the worker was being restarted each ~30 seconds, as the Slot was
> being notified of a changing blob everytime _updateBlobs_ ran.
> I created a resources folder (with dummy files) under the root of the
> classpath and the problem is now solved.
>
> However, if I understand correctly, the resources folder is only required
> for _multilang_. Our topologies do not use _multilang_ and this do not happen
> in Storm 1.1.3 for instance.
>
> Happy to submit MR.
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