[YARN-3937] Introducing CANCEL_PREEMPTION event to notify Scheduler and AM when a container is no longer to be preempted

• Type: Sub-task
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 2.7.1
• Component/s: capacityscheduler
• Assignee: Sunil G
• Reporter: Sunil G
• Created: 17/Jul/15 10:31
• Updated: 19/Aug/15 17:35

Description

As discussed in YARN-3784, there are scenarios like few other applications released containers or same application has revoked its resource requests. In these cases, we may not have to preempt a container which would have been marked for preemption earlier.
Introduce a new event to remove such containers if present in the to-be-preempted list of scheduler or inform AM about such a scenario.