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https://issues.apache.org/jira/browse/FLINK-23190?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17381794#comment-17381794
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loyi commented on FLINK-23190:
------------------------------
[~trohrmann] Thanks for your patience. I have implement a version based on
flink-1.13.1, and then I will use two real examples for comparison below.
h2. Example 1:
This job could make completely evenly allocation in theory.
// job description
StreamExecutionEnvironment env;
env.addSource(...).name("a").setParallelism(10).
map(...).name("b").setParallelism(30)
.map(...).name("c").setParallelism(40)
.addSink(...).name("d").setParallelism(20);
//We specify -ys 4 , that means the job will apply for 10 TaskExecutors.
flink run -yjm 2048 -ytm 2048 -ys 4 -m yarn-cluster -c
com.loyi.flink.demo.Bootstrap -d /home/deploy/flink-demo.jar
!image-2021-07-16-10-34-30-700.png|width=1042,height=219!
*flink-1.13.1-official*(default config) operator's subtask distribution:
||Operator||TM-1||TM-2||TM-3||TM-4||TM-5||TM-6||TM-7||TM-8||TM-9||TM-10||
|a|0|1|2|0|0|1|2|2|2|0|
|b|4|1|3|3|4|4|3|3|3|2|
|c|4|4|4|4|4|4|4|4|4|4|
|d|3|1|3|1|4|2|2|2|0|2|
*flink-1.13.1-official*(with cluster.evenly-spread-out-slots: true) operator's
subtask distribution:
||Operator||TM-1||TM-2||TM-3||TM-4||TM-5||TM-6||TM-7||TM-8||TM-9||TM-10||
|a|1|1|0|2|0|3|1|0|0|2|
|b|4|1|3|4|4|3|4|2|3|2|
|c|4|4|4|4|4|4|4|4|4|4|
|d|3|1|3|2|3|2|2|1|2|1|
*flink-1.13.1-patch*(default config) operator's subtask distribution:
||Operator||TM-1||TM-2||TM-3||TM-4||TM-5||TM-6||TM-7||TM-8||TM-9||TM-10||
|a|1|1|1|1|1|1|1|1|1|1|
|b|3|3|3|3|3|3|3|3|3|3|
|c|4|4|4|4|4|4|4|4|4|4|
|d|2|2|2|2|2|2|2|2|2|2|
*flink-1.13.1-patch*(with jobmanager.scheduler: adaptive) operator's subtask
distribution:
||Operator||TM-1||TM-2||TM-3||TM-4||TM-5||TM-6||TM-7||TM-8||TM-9||TM-10||
|a|1|1|1|1|1|1|1|1|1|1|
|b|3|3|3|3|3|3|3|3|3|3|
|c|4|4|4|4|4|4|4|4|4|4|
|d|2|2|2|2|2|2|2|2|2|2|
h2. Example 2:
We will construct a job that couldn't acheive absolutely evenly allocation.
//job description is the same with above.
StreamExecutionEnvironment env;
env.addSource(...).name("a").setParallelism(10).
map(...).name("b").setParallelism(30)
.map(...).name("c").setParallelism(40)
.addSink(...).name("d").setParallelism(20);
//We specify -ys 3 , that means the job will apply for 14 TaskExecutors.
flink run -yjm 2048 -ytm 2048 -ys 3 -m yarn-cluster -c
com.loyi.flink.demo.Bootstrap -d /home/deploy/flink-demo.jar
*flink-1.13.1-official*(default config) operator's subtask distribution:
||Operator||TM-1||TM-2||TM-3||TM-4||TM-5||TM-6||TM-7||TM-8||TM-9||TM-10||TM-11||TM-12||TM-13||TM-14||
|a|3|1|0|3|1|1|1|0|0|0|0|0|0|0|
|b|3|3|3|3|2|2|2|1|3|2|3|2|1|0|
|c|3|3|3|3|3|3|3|3|3|1|3|3|3|3|
|d|2|2|1|2|3|1|1|1|1|1|2|2|1|0|
*flink-1.13.1-official*(with cluster.evenly-spread-out-slots: true) operator's
subtask distribution:
||Operator||TM-1||TM-2||TM-3||TM-4||TM-5||TM-6||TM-7||TM-8||TM-9||TM-10||TM-11||TM-12||TM-13||TM-14||
|a|2|1|1|1|2|2|1|0|0|0|0|0|0|0|
|b|3|3|2|1|1|3|3|2|1|3|2|3|3|0|
|c|3|3|3|1|3|3|3|3|3|3|3|3|3|3|
|d|1|2|2|1|2|3|1|2|2|3|1|0|0|0|
*flink-1.13.1-patch*(default config) operator's subtask distribution:
||Operator||TM-1||TM-2||TM-3||TM-4||TM-5||TM-6||TM-7||TM-8||TM-9||TM-10||TM-11||TM-12||TM-13||TM-14||
|a|1|1|1|1|1|0|1|1|0|1|0|1|0|1|
|b|3|2|2|2|2|2|3|2|2|2|2|2|2|2|
|c|3|3|3|3|3|3|3|3|3|3|3|3|1|3|
|d|2|1|2|1|1|1|2|2|1|2|1|2|2|0|
*flink-1.13.1-patch*(with jobmanager.scheduler: adaptive) operator's subtask
distribution:
||Operator||TM-1||TM-2||TM-3||TM-4||TM-5||TM-6||TM-7||TM-8||TM-9||TM-10||TM-11||TM-12||TM-13||TM-14||
|a|1|0|0|1|1|1|1|0|0|1|1|1|1|1|
|b|2|2|2|2|3|3|3|2|1|2|2|2|2|2|
|c|3|3|3|3|3|3|3|3|1|3|3|3|3|3|
|d|1|1|1|1|2|2|2|1|1|2|1|2|1|2|
We can see that the patch has a better allocation effect, and spread out each
operator across all TaskExecutors as possibly as evenly as it can.
> 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
> Attachments: image-2021-07-16-10-34-30-700.png
>
>
> 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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