- All Implemented Interfaces:
public class BalancedShardsAllocator extends java.lang.Object implements ShardsAllocatorThe
BalancedShardsAllocatorre-balances the nodes allocations within an cluster based on a
BalancedShardsAllocator.WeightFunction. The clusters balance is defined by four parameters which can be set in the cluster update API that allows changes in real-time:
cluster.routing.allocation.balance.shard- The shard balance defines the weight factor for shards allocated on a
cluster.routing.allocation.balance.index- The index balance defines a factor to the number of
ShardRoutings per index allocated on a specific node
cluster.routing.allocation.balance.threshold- A threshold to set the minimal optimization value of operations that should be performed
These parameters are combined in a
BalancedShardsAllocator.WeightFunctionthat allows calculation of node weights which are used to re-balance shards based on global as well as per-index factors.
Modifier and Type Method Description
allocate(RoutingAllocation allocation)Allocates shards to nodes in the cluster.
decideShardAllocation(ShardRouting shard, RoutingAllocation allocation)Returns the decision for where a shard should reside in the cluster.
getIndexBalance()Returns the index related weight factor.
getShardBalance()Returns the shard related weight factor.
getThreshold()Returns the currently configured delta threshold
public void allocate(RoutingAllocation allocation)Description copied from interface:
ShardsAllocatorAllocates shards to nodes in the cluster. An implementation of this method should: - assign unassigned shards - relocate shards that cannot stay on a node anymore - relocate shards to find a good shard balance in the cluster
public ShardAllocationDecision decideShardAllocation(ShardRouting shard, RoutingAllocation allocation)Description copied from interface:
ShardsAllocatorReturns the decision for where a shard should reside in the cluster. If the shard is unassigned, then the
AllocateUnassignedDecisionwill be non-null. If the shard is not in the unassigned state, then the
MoveDecisionwill be non-null. This method is primarily used by the cluster allocation explain API to provide detailed explanations for the allocation of a single shard. Implementations of the
ShardsAllocator.allocate(RoutingAllocation)method may use the results of this method implementation to decide on allocating shards in the routing table to the cluster. If an implementation of this interface does not support explaining decisions for a single shard through the cluster explain API, then this method should throw a
public float getThreshold()Returns the currently configured delta threshold
public float getIndexBalance()Returns the index related weight factor.
public float getShardBalance()Returns the shard related weight factor.