[MAPREDUCE-4982] AM hung with one pending map task

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Duplicate
• Affects Version/s: 0.23.6
• Component/s: mr-am
• Assignee: Unassigned
• Reporter: Jason Darrell Lowe
• Created: 06/Feb/13 19:26
• Updated: 13/Feb/13 02:00
• Resolved: 08/Feb/13 23:11

Description

Saw a job that hung with one pending map task that never ran. The task was in the SCHEDULED state with a single attempt that was in the UNASSIGNED state. The AM looked like it was waiting for a container from the RM, but the RM was never granting it the one container it needed.

I suspect the AM botched the container request bookkeeping somehow. More details to follow.

Issue Links

• duplicates: MAPREDUCE-4893 MR AppMaster can do sub-optimal assignment of containers to map tasks leading to poor node locality
• is related to: MAPREDUCE-5002 AM could potentially allocate a reduce container to a map attempt