Package org.elasticsearch.gateway

Class BaseGatewayShardAllocator

java.lang.Object

org.elasticsearch.gateway.BaseGatewayShardAllocator

Direct Known Subclasses:

PrimaryShardAllocator, ReplicaShardAllocator

public abstract class BaseGatewayShardAllocator
extends java.lang.Object

An abstract class that implements basic functionality for allocating shards to nodes based on shard copies that already exist in the cluster. Individual implementations of this class are responsible for providing the logic to determine to which nodes (if any) those shards are allocated.

Field Summary

Fields

Modifier and Type	Field	Description
protected org.apache.logging.log4j.Logger	logger

Constructor Summary

Constructors

Constructor	Description
BaseGatewayShardAllocator()

Method Summary

Modifier and Type	Method	Description
void	allocateUnassigned(RoutingAllocation allocation)	Allocate unassigned shards to nodes (if any) where valid copies of the shard already exist.
protected java.util.List<NodeAllocationResult>	buildDecisionsForAllNodes(ShardRouting shard, RoutingAllocation allocation)	Builds decisions for all nodes in the cluster, so that the explain API can provide information on allocation decisions for each node, while still waiting to allocate the shard (e.g.
abstract AllocateUnassignedDecision	makeAllocationDecision(ShardRouting unassignedShard, RoutingAllocation allocation, org.apache.logging.log4j.Logger logger)	Make a decision on the allocation of an unassigned shard.

Methods inherited from class java.lang.Object

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

Field Detail

logger

protected final org.apache.logging.log4j.Logger logger

Constructor Detail

BaseGatewayShardAllocator

public BaseGatewayShardAllocator()

Method Detail

allocateUnassigned

public void allocateUnassigned(RoutingAllocation allocation)

Allocate unassigned shards to nodes (if any) where valid copies of the shard already exist. It is up to the individual implementations of makeAllocationDecision(ShardRouting, RoutingAllocation, Logger) to make decisions on assigning shards to nodes.

Parameters:

allocation - the allocation state container object

makeAllocationDecision

public abstract AllocateUnassignedDecision makeAllocationDecision(ShardRouting unassignedShard,
                                                                  RoutingAllocation allocation,
                                                                  org.apache.logging.log4j.Logger logger)

Make a decision on the allocation of an unassigned shard. This method is used by allocateUnassigned(RoutingAllocation) to make decisions about whether or not the shard can be allocated by this allocator and if so, to which node it will be allocated.

Parameters:

unassignedShard - the unassigned shard to allocate

allocation - the current routing state

logger - the logger

Returns:

an AllocateUnassignedDecision with the final decision of whether to allocate and details of the decision

buildDecisionsForAllNodes

protected java.util.List<NodeAllocationResult> buildDecisionsForAllNodes(ShardRouting shard,
                                                                         RoutingAllocation allocation)

Builds decisions for all nodes in the cluster, so that the explain API can provide information on allocation decisions for each node, while still waiting to allocate the shard (e.g. due to fetching shard data).