org.elasticsearch.cluster.routing.allocation.allocator

Class BalancedShardsAllocator.Balancer

java.lang.Object

org.elasticsearch.cluster.routing.allocation.allocator.BalancedShardsAllocator.Balancer

Enclosing class:

BalancedShardsAllocator

public static class BalancedShardsAllocator.Balancer
extends Object

A BalancedShardsAllocator.Balancer

Constructor Summary

Constructors

Constructor and Description
Balancer(ESLogger logger, RoutingAllocation allocation, BalancedShardsAllocator.WeightFunction weight, float threshold)

Method Summary

Modifier and Type	Method and Description
float	avgShardsPerNode() Returns the global average of shards per node
float	avgShardsPerNode(String index) Returns the average of shards per node for the given index
boolean	balance() Balances the nodes on the cluster model according to the weight function.
boolean	moveShards() Move started shards that can not be allocated to a node anymore For each shard to be moved this function executes a move operation to the minimal eligible node with respect to the weight function.

Methods inherited from class java.lang.Object

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

Constructor Detail

Balancer

public Balancer(ESLogger logger,
                RoutingAllocation allocation,
                BalancedShardsAllocator.WeightFunction weight,
                float threshold)

Method Detail

avgShardsPerNode

public float avgShardsPerNode(String index)

Returns the average of shards per node for the given index

avgShardsPerNode

public float avgShardsPerNode()

Returns the global average of shards per node

balance

public boolean balance()

Balances the nodes on the cluster model according to the weight function. The configured threshold is the minimum delta between the weight of the maximum node and the minimum node according to the BalancedShardsAllocator.WeightFunction. This weight is calculated per index to distribute shards evenly per index. The balancer tries to relocate shards only if the delta exceeds the threshold. If the default case the threshold is set to 1.0 to enforce gaining relocation only, or in other words relocations that move the weight delta closer to 0.0

Returns:

true if the current configuration has been changed, otherwise false

moveShards

public boolean moveShards()

Move started shards that can not be allocated to a node anymore For each shard to be moved this function executes a move operation to the minimal eligible node with respect to the weight function. If a shard is moved the shard will be set to ShardRoutingState.RELOCATING and a shadow instance of this shard is created with an incremented version in the state ShardRoutingState.INITIALIZING.

Returns:

true if the allocation has changed, otherwise false