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https://issues.apache.org/jira/browse/MAPREDUCE-7169?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16770272#comment-16770272
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Zhaohui Xin edited comment on MAPREDUCE-7169 at 2/17/19 2:39 AM:
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After [YARN-6592|https://issues.apache.org/jira/browse/YARN-6592], it's easily
to solve this problem using new resource request class, SchedulingRequest.
Currently, maybe it's better just remove last attempt's node host in next
resource request for speculation attempt. Just like,
{code:java}
taskAttempt.dataLocalHosts =
taskAttempt.dataLocalHosts.remove(lastAttempt.host);
//allocate resource for this speculation attempt.
// code...{code}
[~bibinchundatt], [~ajisakaa]. How do you think this?
was (Author: uranus):
Maybe it's better just remove last attempt's node host in next resource request
for speculation attempt. Just like,
{code:java}
taskAttempt.dataLocalHosts =
taskAttempt.dataLocalHosts.remove(lastAttempt.host);
//allocate resource for this speculation attempt.
{code}
> 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: Zhaohui Xin
> Priority: Major
> Attachments: 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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