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https://issues.apache.org/jira/browse/FLINK-23190?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17381369#comment-17381369
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Till Rohrmann commented on FLINK-23190:
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{{cluster.evenly-spread-out-slots}} also works for active deployments. What is
not working is the {{ResourceManager}} part of this option because the active
{{ResourceManager}} can allocate new containers. The {{JobMaster}} part should
work, though.
In your example (the one in the ticket description), all operators will be in
the same {{SlotSharingGroup}}. That's why the example won't work. I think you
might confuse {{JobVertexID}} and {{SlotSharingGroups}} here.
I mean you can try to implement your idea and back it up with some experimental
results that show that your approach produces better results. Maybe this is the
easiest way forward to better evaluate your proposal.
> Make task-slot allocation much more evenly
> ------------------------------------------
>
> Key: FLINK-23190
> URL: https://issues.apache.org/jira/browse/FLINK-23190
> Project: Flink
> Issue Type: Improvement
> Components: Runtime / Coordination
> Affects Versions: 1.12.3
> Reporter: loyi
> Priority: Major
>
> FLINK-12122 only guarantees spreading out tasks across the set of TMs which
> are registered at the time of scheduling, but our jobs are all runing on
> active yarn mode， the job with smaller source parallelism offen cause
> load-balance issues.
>
> For this job:
> {code:java}
> // -ys 4 means 10 taskmanagers
> env.addSource(...).name("A").setParallelism(10).
> map(...).name("B").setParallelism(30)
> .map(...).name("C").setParallelism(40)
> .addSink(...).name("D").setParallelism(20);
> {code}
>
> Flink-1.12.3 task allocation:
> ||operator||tm1 ||tm2||tm3||tm4||tm5||5m6||tm7||tm8||tm9||tm10||
> |A|
> 1|{color:#de350b}2{color}|{color:#de350b}2{color}|1|1|{color:#de350b}3{color}|{color:#de350b}0{color}|{color:#de350b}0{color}|{color:#de350b}0{color}|{color:#de350b}0{color}|
> |B|3|3|3|3|3|3|3|3|{color:#de350b}2{color}|{color:#de350b}4{color}|
> |C|4|4|4|4|4|4|4|4|4|4|
> |D|2|2|2|2|2|{color:#de350b}1{color}|{color:#de350b}1{color}|2|2|{color:#de350b}4{color}|
>
> Suggestions:
> When TaskManger start register slots to slotManager , current processing
> logic will choose the first pendingSlot which meet its resource
> requirements. The "random" strategy usually causes uneven task allocation
> when source-operator's parallelism is significantly below process-operator's.
> A simple feasible idea is {color:#de350b}partition{color} the current
> "{color:#de350b}pendingSlots{color}" by their "JobVertexIds" (such as let
> AllocationID bring the detail) , then allocate the slots proportionally to
> each JobVertexGroup.
>
> For above case, the 40 pendingSlots could be divided into 4 groups：
> [ABCD]: 10 // A、B、C、D reprents {color:#de350b}jobVertexId{color}
> [BCD]: 10
> [CD]: 10
> [D]: 10
>
> Every taskmanager will provide 4 slots one time, and each group will get 1
> slot according their proportion (1/4), the final allocation result is below:
> [ABCD] : deploye on 10 different taskmangers
> [BCD]: deploye on 10 different taskmangers
> [CD]: deploye on 10 different taskmangers
> [D]: deploye on 10 different taskmangers
>
> I have implement a [concept
> code|https://github.com/saddays/flink/commit/dc82e60a7c7599fbcb58c14f8e3445bc8d07ace1]
> based on Flink-1.12.3 , the patch version has {color:#de350b}fully
> evenly{color} task allocation , and works well on my workload . Are there
> other point that have not been considered or does it conflict with future
> plans? Sorry for my poor english.
>
>
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