[YARN-4333] Fair scheduler should support preemption within a leaf queue

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Duplicate
• Affects Version/s: 2.6.0
• Component/s: fairscheduler
• Assignee: Tao Jie
• Reporter: Tao Jie
• Created: 05/Nov/15 03:29
• Updated: 31/Aug/16 03:48
• Resolved: 31/Aug/16 03:45

Description

Now each app in fair scheduler is allocated its fairshare, however fairshare resource is not ensured even if fairSharePreemption is enabled.
Consider:
1, When the cluster is idle, we submit app1 to queueA,which takes maxResource of queueA.
2, Then the cluster becomes busy, but app1 does not release any resource, queueA resource usage is over its fairshare
3, Then we submit app2(maybe with higher priority) to queueA. Now app2 has its own fairshare, but could not obtain any resource, since queueA is still over its fairshare and resource will not assign to queueA anymore. Also, preemption is not triggered in this case.
So we should allow preemption within queue, when app is starved for fairshare.

Issue Links

• is part of: YARN-4752 FairScheduler should preempt for a ResourceRequest and all preempted containers should be on the same node