Module org.elasticsearch.server

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

Class NodeReplacementAllocationDecider

java.lang.Object

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

org.elasticsearch.cluster.routing.allocation.decider.NodeReplacementAllocationDecider

public class NodeReplacementAllocationDecider
extends AllocationDecider

An allocation decider that ensures that all the shards allocated to the node scheduled for removal are relocated to the replacement node. It also ensures that auto-expands replicas are expanded to only the replacement source or target (not both at the same time) and only of the shards that were already present on the source node.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	NAME

Constructor Summary

Constructors

Constructor	Description
NodeReplacementAllocationDecider()

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	canAllocateReplicaWhenThereIsRetentionLease(ShardRouting shardRouting, RoutingNode node, RoutingAllocation allocation)	Returns a Decision whether the given replica shard can be allocated to the given node when there is an existing retention lease already existing on the node (meaning it has been allocated there previously) This method does not actually check whether there is a retention lease, that is the responsibility of the caller.
Decision	canForceAllocateDuringReplace(ShardRouting shardRouting, RoutingNode node, RoutingAllocation allocation)	Returns a Decision whether the given shard can be forced to the given node in the event that the shard's source node is being replaced.
Decision	canRemain(IndexMetadata indexMetadata, ShardRouting shardRouting, RoutingNode node, RoutingAllocation allocation)	Returns a Decision whether the given shard routing can be remain on the given node.
Decision	shouldAutoExpandToNode(IndexMetadata indexMetadata, DiscoveryNode node, RoutingAllocation allocation)	Returns a Decision whether shards of the given index should be auto-expanded to this node at this state of the RoutingAllocation.

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

canAllocate, canAllocate, canForceAllocatePrimary, canRebalance, canRebalance, getForcedInitialShardAllocationToNodes

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

Constructor Details

NodeReplacementAllocationDecider

public NodeReplacementAllocationDecider()

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(IndexMetadata indexMetadata,
 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

shouldAutoExpandToNode

public Decision shouldAutoExpandToNode(IndexMetadata indexMetadata,
 DiscoveryNode node,
 RoutingAllocation allocation)

Description copied from class: AllocationDecider

Returns a Decision whether shards of the given index should be auto-expanded to this node at this state of the RoutingAllocation. The default is Decision.ALWAYS.

Overrides:

shouldAutoExpandToNode in class AllocationDecider

canForceAllocateDuringReplace

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

Description copied from class: AllocationDecider

Returns a Decision whether the given shard can be forced to the given node in the event that the shard's source node is being replaced. This allows nodes using a replace-type node shutdown to override certain deciders in the interest of moving the shard away from a node that *must* be removed. It defaults to returning "YES" and must be overridden by deciders that opt-out to having their other NO decisions *not* overridden while vacating. The caller is responsible for first checking: - that a replacement is ongoing - the shard routing's current node is the source of the replacement

Overrides:

canForceAllocateDuringReplace in class AllocationDecider

canAllocateReplicaWhenThereIsRetentionLease

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

Description copied from class: AllocationDecider

Returns a Decision whether the given replica shard can be allocated to the given node when there is an existing retention lease already existing on the node (meaning it has been allocated there previously) This method does not actually check whether there is a retention lease, that is the responsibility of the caller. It defaults to the same value as canAllocate.

Overrides:

canAllocateReplicaWhenThereIsRetentionLease in class AllocationDecider