Ram Venkatesh created YARN-2362: ----------------------------------- Summary: Capacity Scheduler apps with requests that exceed capacity can starve pending apps Key: YARN-2362 URL: https://issues.apache.org/jira/browse/YARN-2362 Project: Hadoop YARN Issue Type: Bug Components: capacityscheduler Affects Versions: 2.4.1 Reporter: Ram Venkatesh
Cluster configuration: Total memory: 8GB yarn.scheduler.minimum-allocation-mb 256 yarn.scheduler.capacity.maximum-am-resource-percent 1 (100%, test only config) App 1 makes a request for 4.6 GB, succeeds, app transitions to RUNNING state. It subsequently makes a request for 4.6 GB, which cannot be granted and it waits. App 2 makes a request for 1 GB - never receives it, so the app stays in the ACCEPTED state for ever. I think this can happen in leaf queues that are near capacity. The fix is likely in LeafQueue.java assignContainers near line 861, where it returns if the assignment would exceed queue capacity, instead of checking if requests for other active applications can be met. // Check queue max-capacity limit if (!assignToQueue(clusterResource, required)) { - return NULL_ASSIGNMENT; + break; } With this change, the scenario above allows App 2 to start and finish while App 1 continues to wait. I have a patch available, but wondering if the current behavior is by design. -- This message was sent by Atlassian JIRA (v6.2#6252)