software.amazon.kinesis.coordinator.assignment

Class VarianceBasedLeaseAssignmentDecider

java.lang.Object

software.amazon.kinesis.coordinator.assignment.VarianceBasedLeaseAssignmentDecider

All Implemented Interfaces:

LeaseAssignmentDecider

public final class VarianceBasedLeaseAssignmentDecider
extends Object
implements LeaseAssignmentDecider

VarianceBasedLeaseAssignmentDecider This implementation of LeaseAssignmentDecider performs lease assignment by considering the WorkerMetricStats values of workers with respect to fleet level average of that WorkerMetricStats. Rebalanced leases are assigned to workers which has maximum capacity to in terms of throughput to reach fleet level across the WorkerMetricStats value. In case of multiple WorkerMetricStats, the capacity to reach fleet level average is determined by outlier WorkerMetricStats. To minimize the variance, the algorithm picks the fleet level average of the WorkerMetricStats for workers as a pivot point and uses it to determine workers to take leases from and then assign to other workers. The threshold for considering a worker for re-balance is configurable via reBalanceThreshold. During reassignments the dampeningPercentageValue is used to achieve critical dampening.

Constructor Summary

Constructors

Constructor and Description
VarianceBasedLeaseAssignmentDecider(software.amazon.kinesis.coordinator.assignment.LeaseAssignmentManager.InMemoryStorageView inMemoryStorageView, int dampeningPercentageValue, int reBalanceThreshold, boolean allowThroughputOvershoot)

Method Summary

Modifier and Type	Method and Description
void	assignExpiredOrUnassignedLeases(List<Lease> expiredOrUnAssignedLeases) Assigns expiredOrUnAssignedLeases to the available workers.
void	balanceWorkerVariance() Performs the balancing of the throughput assigned to workers based on the WorkerMetricsValues of worker with respect to fleet level average.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

VarianceBasedLeaseAssignmentDecider

public VarianceBasedLeaseAssignmentDecider(software.amazon.kinesis.coordinator.assignment.LeaseAssignmentManager.InMemoryStorageView inMemoryStorageView,
                                           int dampeningPercentageValue,
                                           int reBalanceThreshold,
                                           boolean allowThroughputOvershoot)

Method Detail

assignExpiredOrUnassignedLeases

public void assignExpiredOrUnassignedLeases(List<Lease> expiredOrUnAssignedLeases)

Description copied from interface: LeaseAssignmentDecider

Assigns expiredOrUnAssignedLeases to the available workers.

Specified by:

assignExpiredOrUnassignedLeases in interface LeaseAssignmentDecider

balanceWorkerVariance

public void balanceWorkerVariance()

Performs the balancing of the throughput assigned to workers based on the WorkerMetricsValues of worker with respect to fleet level average. Each WorkerMetricStats is treated independently to determine workers for re-balance computed (computed based on reBalanceThreshold) are determined. The magnitude of throughput to take is determined by how much worker is away from the average of that WorkerMetricStats across fleet and in case of multiple WorkerMetricStats, the one with maximum magnitude of throughput is considered.

Specified by:

balanceWorkerVariance in interface LeaseAssignmentDecider