YARN-1051 enables SLA support by allowing users to reserve cluster capacity ahead of time. YARN-1710 introduced a greedy agent for placing user reservations. The greedy agent makes fast placement decisions but at the cost of ignoring the cluster committed resources, which might result in blocking the cluster resources for certain periods of time, and in turn rejecting some arriving jobs.
We propose LowCost – a new cost-based planning algorithm. LowCost “spreads” the demand of the job throughout the allowed time-window according to a global, load-based cost function.