[YARN-10396] Max applications calculation per queue disregards queue level settings in absolute mode

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.2.2, 3.4.0, 3.3.1
• Component/s: capacity scheduler
• Hadoop Flags: Reviewed
• Assignee: Benjamin Teke
• Reporter: Benjamin Teke
• Created: 12/Aug/20 12:01
• Updated: 16/Feb/22 13:29
• Resolved: 18/Nov/20 05:31

Description

Looking at the following code in org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.ParentQueue.java#L1126

int maxApplications = (int) (conf.getMaximumSystemApplications()
    * childQueue.getQueueCapacities().getAbsoluteCapacity(label));
leafQueue.setMaxApplications(maxApplications);

In Absolute Resources mode, setting the number of maximum applications on queue level gets overridden with the system level setting scaled down to the available resources. This means that the only way to set the maximum number of applications is to change the queue's resource pool. This line should consider the queue's {{yarn.scheduler.capacity.{queuepath}.maximum-applications }}setting.