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https://issues.apache.org/jira/browse/YARN-4353?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15004558#comment-15004558
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Vinod Kumar Vavilapalli commented on YARN-4353:
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[~templedf], added you to the YARN contributors list, so you should be able to
assign this and any future tickets to yourselves from now on.
Regarding this JIRA, a lots of places in NM *do* depend on the user/group
information, so we should be extra careful about how we do this. I get a
feeling there is an alternative fool-proof approach for this - do the getGroups
call once in the NodeManager and pass it down everywhere so we don't repeatedly
do it downstream.
> Provide short circuit user group mapping for NM/AM
> --------------------------------------------------
>
> Key: YARN-4353
> URL: https://issues.apache.org/jira/browse/YARN-4353
> Project: Hadoop YARN
> Issue Type: Improvement
> Components: nodemanager
> Affects Versions: 2.7.1
> Reporter: Daniel Templeton
>
> When the NM launches an AM, the {{ContainerLocalizer}} gets the current user
> from {{UserGroupInformation}}, which triggers user group mapping, even though
> the user groups are never accessed. If secure LDAP is configured for group
> mapping, then there are some additional complications created by the
> unnecessary group resolution. Additionally, it adds unnecessary latency to
> the container launch time.
> To address the issue, before getting the current user, the
> {{ContainerLocalizer}} should configure {{UserGroupInformation}} with a null
> group mapping service that quickly and quietly returns an empty group list
> for all users.
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