[MAPREDUCE-3274] Race condition in MR App Master Preemtion can cause a dead lock

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 0.23.0, 0.24.0
• Fix Version/s: 0.23.0, 0.24.0
• Component/s: applicationmaster, mrv2
• Target Version/s: 0.23.0, 0.24.0
• Hadoop Flags: Reviewed
• Assignee: Robert Joseph Evans
• Reporter: Robert Joseph Evans
• Created: 26/Oct/11 21:48
• Updated: 15/Nov/11 00:48
• Resolved: 30/Oct/11 11:34

Description

There appears to be a race condition in the MR App Master in relation to preempting reducers to let a mapper run. In the particular case that I have been debugging a reducer was selected for preemption that did not have a container assigned to it yet. When the container became available that reduce started running and the previous TA_KILL event appears to have been ignored.