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

Class ShardsLimitAllocationDecider

java.lang.Object

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	Description
static Setting<Integer>	CLUSTER_TOTAL_SHARDS_PER_NODE_SETTING	Controls the maximum number of shards per node on a global level.
static Setting<Integer>	INDEX_TOTAL_SHARDS_PER_NODE_SETTING	Controls the maximum number of shards per index on a single Elasticsearch node.
static String	NAME

Constructor Summary

Constructors

Constructor	Description
ShardsLimitAllocationDecider(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	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, canForceAllocatePrimary, canRebalance, canRebalance, 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

INDEX_TOTAL_SHARDS_PER_NODE_SETTING

public static final Setting<Integer> INDEX_TOTAL_SHARDS_PER_NODE_SETTING

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

CLUSTER_TOTAL_SHARDS_PER_NODE_SETTING

public static final Setting<Integer> CLUSTER_TOTAL_SHARDS_PER_NODE_SETTING

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

Constructor Details

ShardsLimitAllocationDecider

public ShardsLimitAllocationDecider(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

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