Types of queues
As mentioned earlier in this chapter, YARN defines two schedulers (capacity and fair schedulers). These schedulers use their own implementation of the queue interface. The following diagram represents a class diagram for different queues defined in YARN:
CapacityScheduler Queue (CSQueue)
CSQueue is an interface that extends the Queue interface. It is defined in the org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity package. The CSQueue interface represents a queue structure for a node in the tree of hierarchical queues for CapacityScheduler.
The two classes that implement the CSQueue interface are as follows:
ParentQueueLeafQueue
The properties associated with a CapacityScheduler queue are as follows:
yarn.scheduler.capacity.<queue-path>.capacity: This is a float value that specifies the capacity of the queue in percentage (%). At each level of queues (hierarchical queues), the sum of capacities for all queues must be equal to 100. In order to provide...
