[jira] [Created] (YARN-10528) maxAMShare should only be accepted for leaf queues, not parent queues

["Siddharth Ahuja (Jira)" <ji...@apache.org>]

Siddharth Ahuja created YARN-10528:
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             Summary: maxAMShare should only be accepted for leaf queues, not parent queues
                 Key: YARN-10528
                 URL: https://issues.apache.org/jira/browse/YARN-10528
             Project: Hadoop YARN
          Issue Type: Bug
            Reporter: Siddharth Ahuja


Based on [Hadoop documentation|https://hadoop.apache.org/docs/current/hadoop-yarn/hadoop-yarn-site/FairScheduler.html], it is clear that {{maxAMShare}} property can only be used for *leaf queues*. This is similar to the {{reservation}} setting.

However, existing code only ensures that the reservation setting is not accepted for "parent" queues (see https://github.com/apache/hadoop/blob/trunk/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/allocation/AllocationFileQueueParser.java#L226 and https://github.com/apache/hadoop/blob/trunk/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/allocation/AllocationFileQueueParser.java#L233) but it is missing the checks for {{maxAMShare}}. Due to this, it is current possible to have an allocation similar to below:

{code}
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<allocations>
    <queue name="root">
        <weight>1.0</weight>
        <schedulingPolicy>drf</schedulingPolicy>
        <aclSubmitApps>*</aclSubmitApps>
        <aclAdministerApps>*</aclAdministerApps>
        <queue name="default">
            <weight>1.0</weight>
            <schedulingPolicy>drf</schedulingPolicy>
        </queue>
        <queue name="users" type="parent">
            <weight>1.0</weight>
            <schedulingPolicy>drf</schedulingPolicy>
            <maxAMShare>1.0</maxAMShare>
        </queue>
    </queue>
    <defaultQueueSchedulingPolicy>fair</defaultQueueSchedulingPolicy>
    <queuePlacementPolicy>
        <rule name="specified" create="true"/>
        <rule name="nestedUserQueue" create="true">
            <rule name="default" create="true" queue="users"/>
        </rule>
        <rule name="default"/>
    </queuePlacementPolicy>
</allocations>
{code}

where {{maxAMShare}} is 1.0f meaning, it is possible allocate 100% of the queue's resources for Application Masters. Notice above that root.users is a parent queue, however, it still gladly accepts {{maxAMShare}}. This is contrary to the documentation and in fact, it is very misleading because the child queues like root.users.<user> actually do not inherit this setting at all and they still go on and use the default of 0.5 instead of 1.0, see the attached screenshot as an example.



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