Package org.elasticsearch.cluster.routing.allocation.decider

Class SameShardAllocationDecider

java.lang.Object

org.elasticsearch.cluster.routing.allocation.decider.AllocationDecider

org.elasticsearch.cluster.routing.allocation.decider.SameShardAllocationDecider

public class SameShardAllocationDecider
extends AllocationDecider

An allocation decider that prevents multiple instances of the same shard to be allocated on the same node. The CLUSTER_ROUTING_ALLOCATION_SAME_HOST_SETTING setting allows to perform a check to prevent allocation of multiple instances of the same shard on a single host, based on host name and host address. Defaults to `false`, meaning that no check is performed by default.

Note: this setting only applies if multiple nodes are started on the same host. Allocations of multiple copies of the same shard on the same node are not allowed independently of this setting.

Field Summary

Fields

Modifier and Type	Field	Description
static Setting<Boolean>	CLUSTER_ROUTING_ALLOCATION_SAME_HOST_SETTING
static String	NAME

Constructor Summary

Constructors

Constructor	Description
SameShardAllocationDecider(Settings settings, ClusterSettings clusterSettings)

Method Summary

Modifier and Type	Method	Description
Decision	canAllocate(ShardRouting shardRouting, RoutingNode node, RoutingAllocation allocation)	Returns a Decision whether the given shard routing can be allocated on the given node.
Decision	canForceAllocatePrimary(ShardRouting shardRouting, RoutingNode node, RoutingAllocation allocation)	Returns a Decision whether the given primary shard can be forcibly allocated on the given node.

Methods inherited from class org.elasticsearch.cluster.routing.allocation.decider.AllocationDecider

canAllocate, canAllocate, canRebalance, canRebalance, canRemain, shouldAutoExpandToNode

Methods inherited from class java.lang.Object

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

Field Details

NAME

public static final String NAME

See Also:

Constant Field Values

CLUSTER_ROUTING_ALLOCATION_SAME_HOST_SETTING

public static final Setting<Boolean> CLUSTER_ROUTING_ALLOCATION_SAME_HOST_SETTING

Constructor Details

SameShardAllocationDecider

public SameShardAllocationDecider(Settings settings,
 ClusterSettings clusterSettings)

Method Details

canAllocate

public Decision canAllocate(ShardRouting shardRouting,
 RoutingNode node,
 RoutingAllocation allocation)

Description copied from class: AllocationDecider

Returns a Decision whether the given shard routing can be allocated on the given node. The default is Decision.ALWAYS.

Overrides:

canAllocate in class AllocationDecider

canForceAllocatePrimary

public Decision canForceAllocatePrimary(ShardRouting shardRouting,
 RoutingNode node,
 RoutingAllocation allocation)

Description copied from class: AllocationDecider

Returns a Decision whether the given primary shard can be forcibly allocated on the given node. This method should only be called for unassigned primary shards where the node has a shard copy on disk. Note: all implementations that override this behavior should take into account the results of AllocationDecider.canAllocate(ShardRouting, RoutingNode, RoutingAllocation) before making a decision on force allocation, because force allocation should only be considered if all deciders return Decision.NO.

Overrides:

canForceAllocatePrimary in class AllocationDecider