[YARN-4353] Provide short circuit user group mapping for NM/AM

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Won't Fix
• Affects Version/s: 2.7.1
• Component/s: nodemanager
• Hadoop Flags: Reviewed
• Assignee: Daniel Templeton
• Reporter: Daniel Templeton
• Created: 12/Nov/15 21:49
• Updated: 26/Feb/20 05:29
• Resolved: 21/May/18 15:47

Description

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.

Issue Links

• is blocked by: HADOOP-12566 Add NullGroupMapping