[YARN-5255] Move ResourceRequest expansion for Delay Scheduling to the Scheduler

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Assignee: Arun Suresh
• Reporter: Arun Suresh
• Created: 15/Jun/16 05:06
• Updated: 04/Oct/17 01:25

Description

YARN-4879 proposes to enhance the Allocate Request by introducing an id to explicitly identify a ResourceRequest.

Currently, if relaxLocality == true, a Node specific request is expanded to rack and ANY request by the AMRMClient before being sent to the Scheduler. The requires the 3 copies to perform locality specific delay scheduling.

It would be better to perform the expansion in the Scheduler itself, rather than the client, since:

1. The expansion is not really specified in the ApplicationMasterProtocol, a non-java client will have to duplicate the expansion logic.
2. Refactor out a lot of unnecessary code in the AMRMClientImpl