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https://issues.apache.org/jira/browse/YARN-5686?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15610978#comment-15610978
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Varun Saxena commented on YARN-5686:
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+1. Will commit this pending Jenkins.
> DefaultContainerExecutor random working dir algorigthm skews results
> --------------------------------------------------------------------
>
> Key: YARN-5686
> URL: https://issues.apache.org/jira/browse/YARN-5686
> Project: Hadoop YARN
> Issue Type: Bug
> Reporter: Miklos Szegedi
> Assignee: Vrushali C
> Priority: Minor
> Attachments: YARN-5686.001.patch, YARN-5686.002.patch
>
>
> {code}
> long randomPosition = RandomUtils.nextLong() % totalAvailable;
> ...
> while (randomPosition > availableOnDisk[dir]) {
> randomPosition -= availableOnDisk[dir++];
> }
> {code}
> The code above selects a disk based on the random number weighted by the free
> space on each disk respectively. For example, if I have two disks with 100
> bytes each, totalAvailable is 200. The value of randomPosition will be
> 0..199. 0..99 should select the first disk, 100..199 should select the second
> disk inclusively. Random number 100 should select the second disk to be fair
> but this is not the case right now.
> We need to use
> {code}
> while (randomPosition >= availableOnDisk[dir])
> {code}
> instead of
> {code}
> while (randomPosition > availableOnDisk[dir])
> {code}
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