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https://issues.apache.org/jira/browse/MAPREDUCE-7169?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17095502#comment-17095502
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Bilwa S T edited comment on MAPREDUCE-7169 at 4/29/20, 2:40 PM:
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Hi [~ahussein]
{code:java}
The same node will be picked if there are no other available nodes. In
MAPREDUCE-7169.005.patch , what is the expected behavior if the resources
available to run the taskAttempt are only available on the same node? I do not
see this case in the unit test.{code}
Container is not assigned until resources are available on other node. Task
will wait until it gets container on other node. As per use case we do not want
container to be launched on same node as node might have a problem
was (Author: bilwast):
Hi [~ahussein]
{code:java}
The same node will be picked if there are no other available nodes. In
MAPREDUCE-7169.005.patch , what is the expected behavior if the resources
available to run the taskAttempt are only available on the same node? I do not
see this case in the unit test.{code}
Container is not assigned until resources are available on other node.
> Speculative attempts should not run on the same node
> ----------------------------------------------------
>
> Key: MAPREDUCE-7169
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-7169
> Project: Hadoop Map/Reduce
> Issue Type: New Feature
> Components: yarn
> Affects Versions: 2.7.2
> Reporter: Lee chen
> Assignee: Bilwa S T
> Priority: Major
> Attachments: MAPREDUCE-7169-001.patch, MAPREDUCE-7169-002.patch,
> MAPREDUCE-7169-003.patch, MAPREDUCE-7169.004.patch, MAPREDUCE-7169.005.patch,
> image-2018-12-03-09-54-07-859.png
>
>
> I found in all versions of yarn, Speculative Execution may set the
> speculative task to the node of original task.What i have read is only it
> will try to have one more task attempt. haven't seen any place mentioning not
> on same node.It is unreasonable.If the node have some problems lead to tasks
> execution will be very slow. and then placement the speculative task to same
> node cannot help the problematic task.
> In our cluster （version 2.7.2，2700 nodes），this phenomenon appear
> almost everyday.
> !image-2018-12-03-09-54-07-859.png!
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