[MAPREDUCE-4671] AM does not tell the RM about container requests that are no longer needed

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.23.3, 2.0.0-alpha
• Fix Version/s: 0.23.7, 2.1.0-beta
• Target Version/s: 2.0.3-alpha
• Hadoop Flags: Reviewed
• Assignee: Bikas Saha
• Reporter: Bikas Saha
• Created: 20/Sep/12 22:59
• Updated: 27/Aug/13 22:22
• Resolved: 07/Feb/13 07:09

Description

Say the AM wanted a container at hosts h1, h2, h3. After getting a container at h1 it should tell RM that it no longer needs containers at h2, h3. Otherwise on the RM h2, h3 remain valid allocation locations.
The AM RMContainerAllocator does remove these resource requests internally. When the resource request container count drops to 0 then it drops the resource request from its tables but forgets to send the 0 sized request to the RM.

Issue Links

• is duplicated by: MAPREDUCE-4984 AM leaves unwanted node/rack requests after container has been assigned
• relates to: YARN-110 AM releases too many containers due to the protocol