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https://issues.apache.org/jira/browse/SAMZA-70?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13898412#comment-13898412
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Garry Turkington commented on SAMZA-70:
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Is this a dupe of SAMZA-42?
> Create setup class to handle per-job startup setup
> --------------------------------------------------
>
> Key: SAMZA-70
> URL: https://issues.apache.org/jira/browse/SAMZA-70
> Project: Samza
> Issue Type: Bug
> Components: container
> Affects Versions: 0.6.0
> Reporter: Chris Riccomini
>
> There is some Samza job setup that happens before tasks can be run. This
> includes setting up the checkpoint and state management (change log)
> factories. For example, we want to verify that the change log and checkpoint
> topics exist, and if not, create them with the proper number of partitions.
> We should pull this logic into a SetupJob class, and move the execution into
> a new YarnAppMasterListener called SamzaAppMasterSetup, which should do the
> job setup during the init() call. In addition, we should execute the same
> SetupJob class logic in the ProcessJob.submit and ThreadJob.submit methods,
> as well.
> The motivation for this is threefold:
> 1. There is a race condition in the TaskRunner when multiple containers for a
> single job are running in YARN, where each TaskRunner is trying to create the
> checkpoint/change log topics when they don't exist.
> 2. It makes implementing the TaskRunner logic in other languages easier,
> since non-Java TaskRunner implementations won't have to set the topics up.
> The SetupClass will be handled in the AM (under YARN) or in the Java code of
> the ProcessJob/ThreadJob (under local job).
> 3. It gives us a place to run a single chunk of code in controlled, single
> threaded way, before any of the TaskRunners start.
> Some things to consider: is it OK to just hard-code that the SetupJob class
> should always just setup the checkpoint manager and change log topics? Do we
> need to add a setup() method to the lifecycle for everything?
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