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Sandy Ryza commented on YARN-752: --------------------------------- bq. If the user has provided racks - just trust that information instead of resolving and then checking whether the user has provided the correct information. If we do this, I think it would be good at least to log some sort of warnings when the given and expected racks don't match up. The consequences of a user getting it wrong can be pretty subtle. bq. but isn't it possible for users to ask for specific hosts, without specifying racks (Ignoring scheduler implementation here) Currently, it does not make sense for users to ask for specific hosts without specifying racks in any scheduler implementation. Containers may still be scheduled on those nodes, but they will be treated like any other non-local nodes for the purposes of delay-scheduling and locality-specific requests. I believe that this is not just an implementation issue, but a result of the protocol. A scheduler having zero containers requested on rack1, but non-zero containers requested on nodes on rack1, can occur when a single container was requested for any of multiple nodes on rack1. > In AMRMClient, automatically add corresponding rack requests for requested > nodes > -------------------------------------------------------------------------------- > > Key: YARN-752 > URL: https://issues.apache.org/jira/browse/YARN-752 > Project: Hadoop YARN > Issue Type: Improvement > Components: api, applications > Affects Versions: 2.0.4-alpha > Reporter: Sandy Ryza > Assignee: Sandy Ryza > Attachments: YARN-752-1.patch, YARN-752-1.patch, YARN-752.patch > > > A ContainerRequest that includes node-level requests must also include > matching rack-level requests for the racks that those nodes are on. When a > node is present without its rack, it makes sense for the client to > automatically add the node's rack. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira