Scheduling queues

The scheduler assigns the application into a queue by using the identity of the job submitter. We can also configure the queue in the configuration of the application at the time of application submission. The application first falls into the default queue that is shared by all the users and then applications are further divided into different queues. Queues are organized hierarchically and are assigned with weights. These weights indicate the proposition of cluster resources. The following diagram gives a better explanation of the queue hierarchy:

The fair scheduler guarantees the configured minimum amount of resources share to the queue. Remember the guaranteed minimum share of resources is applicable for any application submitted to the queue. If the application is not submitted to any particular queue, then the resources belonging to that queue will be allocated to the queues running the application. These processes make sure that resources are not under utilized and that applications are not suffering resource starvation.