Continuous Scheduling

Enabling or disabling continuous scheduling changes how often YARN schedules, either continuously or based on the node heartbeats.

For larger clusters (more than 75 nodes) seeing heavy YARN workloads, disabling continuous scheduling with the following settings is recommended in general:
  • yarn.scheduler.fair.continuous-scheduling-enabled should be false
  • yarn.scheduler.fair.assignmultiple should be true
On large clusters, continuous scheduling can cause the ResourceManager to appear unresponsive since continuous scheduling iterates through all the nodes in the cluster.

For more information about continuous scheduling tuning, see the following knowledge base article: FairScheduler Tuning with assignmultiple and Continuous Scheduling