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https://issues.apache.org/jira/browse/FLINK-12122?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17013089#comment-17013089
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Till Rohrmann commented on FLINK-12122:
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[~ethanli] there are no plan to backport this feature to {{1.8}}.
[~liuyufei] the feature only guarantees spreading out tasks across the set of
TMs which are registered at the time of scheduling. Hence, when you are using
the active Yarn mode and submit the first job, then there won't be any TMs
registered. Consequently, Flink will allocate the first container, fill it up
and then only allocate a new container. However, if you start Flink in
standalone mode or after your first job finishes on Yarn there are still some
TMs registered, then the next job would be spread out.
[~shazeline] there is currently no random distribution mode. When activating
{{cluster.evenly-spread-out-slots}}, Flink will try to allocate slots from the
TMs so that they are evenly utilized. Additionally, Flink will try to spread
out the subtasks belonging to the same operator equally across the available
slots. Hence, Flink should be able to spread your source tasks out across the
available TMs.
> Spread out tasks evenly across all available registered TaskManagers
> --------------------------------------------------------------------
>
> Key: FLINK-12122
> URL: https://issues.apache.org/jira/browse/FLINK-12122
> Project: Flink
> Issue Type: Sub-task
> Components: Runtime / Coordination
> Affects Versions: 1.6.4, 1.7.2, 1.8.0
> Reporter: Till Rohrmann
> Assignee: Till Rohrmann
> Priority: Major
> Labels: pull-request-available
> Fix For: 1.9.2, 1.10.0
>
> Attachments: image-2019-05-21-12-28-29-538.png,
> image-2019-05-21-13-02-50-251.png
>
> Time Spent: 20m
> Remaining Estimate: 0h
>
> With Flip-6, we changed the default behaviour how slots are assigned to
> {{TaskManages}}. Instead of evenly spreading it out over all registered
> {{TaskManagers}}, we randomly pick slots from {{TaskManagers}} with a
> tendency to first fill up a TM before using another one. This is a regression
> wrt the pre Flip-6 code.
> I suggest to change the behaviour so that we try to evenly distribute slots
> across all available {{TaskManagers}} by considering how many of their slots
> are already allocated.
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