org.elasticsearch.cluster.routing.allocation.decider

Class ShardsLimitAllocationDecider

java.lang.Object

org.elasticsearch.common.component.AbstractComponent

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

org.elasticsearch.cluster.routing.allocation.decider.ShardsLimitAllocationDecider

public class ShardsLimitAllocationDecider
extends AllocationDecider

This AllocationDecider limits the number of shards per node on a per index or node-wide basis. The allocator prevents a single node to hold more than "index.routing.allocation.total_shards_per_node" per index and "cluster.routing.allocation.total_shards_per_node" globally during the allocation process. The limits of this decider can be changed in real-time via a the index settings API.

If "index.routing.allocation.total_shards_per_node" is reset to a negative value shards per index are unlimited per node. Shards currently in the relocating state are ignored by this AllocationDecider until the shard changed its state to either started, inializing or unassigned

Note: Reducing the number of shards per node via the index update API can trigger relocation and significant additional load on the clusters nodes.

Field Summary

Fields

Modifier and Type	Field and Description
static String	CLUSTER_TOTAL_SHARDS_PER_NODE Controls the maximum number of shards per node on a global level.
static String	INDEX_TOTAL_SHARDS_PER_NODE Controls the maximum number of shards per index on a single Elasticsearch node.
static String	NAME

Fields inherited from class org.elasticsearch.common.component.AbstractComponent

deprecationLogger, logger, settings

Constructor Summary

Constructors

Constructor and Description
ShardsLimitAllocationDecider(Settings settings, NodeSettingsService nodeSettingsService)

Method Summary

Methods

Modifier and Type	Method and Description
Decision	canAllocate(RoutingNode node, RoutingAllocation allocation) Returns a Decision whether the given node can allow any allocation at all at this state of the RoutingAllocation.
Decision	canAllocate(ShardRouting shardRouting, RoutingNode node, RoutingAllocation allocation) Returns a Decision whether the given shard routing can be allocated on the given node.
Decision	canRemain(ShardRouting shardRouting, RoutingNode node, RoutingAllocation allocation) Returns a Decision whether the given shard routing can be remain on the given node.

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

canAllocate, canAllocate, canRebalance, canRebalance

Methods inherited from class org.elasticsearch.common.component.AbstractComponent

logDeprecatedSetting, logRemovedSetting, nodeName

Methods inherited from class java.lang.Object

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

Field Detail

NAME

public static final String NAME

See Also:

Constant Field Values

INDEX_TOTAL_SHARDS_PER_NODE

public static final String INDEX_TOTAL_SHARDS_PER_NODE

Controls the maximum number of shards per index on a single Elasticsearch node. Negative values are interpreted as unlimited.

See Also:

Constant Field Values

CLUSTER_TOTAL_SHARDS_PER_NODE

public static final String CLUSTER_TOTAL_SHARDS_PER_NODE

Controls the maximum number of shards per node on a global level. Negative values are interpreted as unlimited.

See Also:

Constant Field Values

Constructor Detail

ShardsLimitAllocationDecider

@Inject
public ShardsLimitAllocationDecider(Settings settings,
                                   NodeSettingsService nodeSettingsService)

Method Detail

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

canRemain

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

Description copied from class: AllocationDecider

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

Overrides:

canRemain in class AllocationDecider

canAllocate

public Decision canAllocate(RoutingNode node,
                   RoutingAllocation allocation)

Description copied from class: AllocationDecider

Returns a Decision whether the given node can allow any allocation at all at this state of the RoutingAllocation. The default is Decision.ALWAYS.

Overrides:

canAllocate in class AllocationDecider