org.elasticsearch.cluster.routing.allocation

Class MoveDecision

java.lang.Object

org.elasticsearch.cluster.routing.allocation.AbstractAllocationDecision

org.elasticsearch.cluster.routing.allocation.MoveDecision

All Implemented Interfaces:

Writeable, ToXContent

public final class MoveDecision
extends AbstractAllocationDecision

Represents a decision to move a started shard, either because it is no longer allowed to remain on its current node or because moving it to another node will form a better cluster balance.

Nested Class Summary

Nested classes/interfaces inherited from interface org.elasticsearch.common.xcontent.ToXContent

ToXContent.DelegatingMapParams, ToXContent.MapParams, ToXContent.Params

Nested classes/interfaces inherited from interface org.elasticsearch.common.io.stream.Writeable

Writeable.Reader<V>, Writeable.Writer<V>

Field Summary

Fields

Modifier and Type	Field and Description
static MoveDecision	NOT_TAKEN a constant representing no decision taken

Fields inherited from class org.elasticsearch.cluster.routing.allocation.AbstractAllocationDecision

nodeDecisions, targetNode

Fields inherited from interface org.elasticsearch.common.xcontent.ToXContent

EMPTY_PARAMS

Constructor Summary

Constructors

Constructor and Description
MoveDecision(StreamInput in)

Method Summary

Modifier and Type	Method and Description
static MoveDecision	cannotRebalance(Decision canRebalanceDecision, AllocationDecision allocationDecision, int currentNodeRanking, java.util.List<NodeAllocationResult> nodeDecisions) Creates a move decision for when rebalancing the shard is not allowed.
static MoveDecision	cannotRemain(Decision canRemainDecision, AllocationDecision allocationDecision, DiscoveryNode assignedNode, java.util.List<NodeAllocationResult> nodeDecisions) Creates a move decision for the shard not being allowed to remain on its current node.
boolean	canRebalanceCluster() Returns true if the shard is allowed to be rebalanced to another node in the cluster, returns false otherwise.
boolean	canRemain() Returns true if the shard can remain on its current node, returns false otherwise.
boolean	equals(java.lang.Object other)
boolean	forceMove() Returns true if the shard cannot remain on its current node and can be moved, returns false otherwise.
AllocationDecision	getAllocationDecision() Returns the AllocationDecision for moving this shard to another node.
Decision	getCanRemainDecision() Returns the decision for the shard being allowed to remain on its current node.
Decision	getClusterRebalanceDecision() Returns the decision for being allowed to rebalance the shard.
int	getCurrentNodeRanking() Gets the current ranking of the node to which the shard is currently assigned, relative to the other nodes in the cluster as reported in NodeAllocationResult.getWeightRanking().
java.lang.String	getExplanation() Gets the explanation for the decision.
int	hashCode()
boolean	isDecisionTaken() Returns true if a decision was taken by the allocator, false otherwise.
static MoveDecision	rebalance(Decision canRebalanceDecision, AllocationDecision allocationDecision, DiscoveryNode assignedNode, int currentNodeRanking, java.util.List<NodeAllocationResult> nodeDecisions) Creates a decision for whether to move the shard to a different node to form a better cluster balance.
static MoveDecision	stay(Decision canRemainDecision) Creates a move decision for the shard being able to remain on its current node, so the shard won't be forced to move to another node.
XContentBuilder	toXContent(XContentBuilder builder, ToXContent.Params params)
MoveDecision	withRemainDecision(Decision canRemainDecision) Creates a new move decision from this decision, plus adding a remain decision.
void	writeTo(StreamOutput out) Write this into the StreamOutput.

Methods inherited from class org.elasticsearch.cluster.routing.allocation.AbstractAllocationDecision

atLeastOneNodeWithYesDecision, checkDecisionState, discoveryNodeToXContent, getNodeDecisions, getTargetNode, nodeDecisionsToXContent, sortNodeDecisions

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.elasticsearch.common.xcontent.ToXContent

isFragment

Field Detail

NOT_TAKEN

public static final MoveDecision NOT_TAKEN

a constant representing no decision taken

Constructor Detail

MoveDecision

public MoveDecision(StreamInput in)
             throws java.io.IOException

Throws:

java.io.IOException

Method Detail

writeTo

public void writeTo(StreamOutput out)
             throws java.io.IOException

Description copied from interface: Writeable

Write this into the StreamOutput.

Specified by:

writeTo in interface Writeable

Overrides:

writeTo in class AbstractAllocationDecision

Throws:

java.io.IOException

stay

public static MoveDecision stay(Decision canRemainDecision)

Creates a move decision for the shard being able to remain on its current node, so the shard won't be forced to move to another node.

cannotRemain

public static MoveDecision cannotRemain(Decision canRemainDecision,
                                        AllocationDecision allocationDecision,
                                        DiscoveryNode assignedNode,
                                        java.util.List<NodeAllocationResult> nodeDecisions)

Creates a move decision for the shard not being allowed to remain on its current node.

Parameters:

canRemainDecision - the decision for whether the shard is allowed to remain on its current node

allocationDecision - the AllocationDecision for moving the shard to another node

assignedNode - the node where the shard should move to

nodeDecisions - the node-level decisions that comprised the final decision, non-null iff explain is true

Returns:

the MoveDecision for moving the shard to another node

cannotRebalance

public static MoveDecision cannotRebalance(Decision canRebalanceDecision,
                                           AllocationDecision allocationDecision,
                                           int currentNodeRanking,
                                           java.util.List<NodeAllocationResult> nodeDecisions)

Creates a move decision for when rebalancing the shard is not allowed.

rebalance

public static MoveDecision rebalance(Decision canRebalanceDecision,
                                     AllocationDecision allocationDecision,
                                     @Nullable
                                     DiscoveryNode assignedNode,
                                     int currentNodeRanking,
                                     java.util.List<NodeAllocationResult> nodeDecisions)

Creates a decision for whether to move the shard to a different node to form a better cluster balance.

isDecisionTaken

public boolean isDecisionTaken()

Description copied from class: AbstractAllocationDecision

Returns true if a decision was taken by the allocator, false otherwise. If no decision was taken, then the rest of the fields in this object cannot be accessed and will throw an IllegalStateException.

Specified by:

isDecisionTaken in class AbstractAllocationDecision

withRemainDecision

public MoveDecision withRemainDecision(Decision canRemainDecision)

Creates a new move decision from this decision, plus adding a remain decision.

forceMove

public boolean forceMove()

Returns true if the shard cannot remain on its current node and can be moved, returns false otherwise. If isDecisionTaken() returns false, then invoking this method will throw an IllegalStateException.

canRemain

public boolean canRemain()

Returns true if the shard can remain on its current node, returns false otherwise. If isDecisionTaken() returns false, then invoking this method will throw an IllegalStateException.

getCanRemainDecision

public Decision getCanRemainDecision()

Returns the decision for the shard being allowed to remain on its current node. If isDecisionTaken() returns false, then invoking this method will throw an IllegalStateException.

canRebalanceCluster

public boolean canRebalanceCluster()

Returns true if the shard is allowed to be rebalanced to another node in the cluster, returns false otherwise. If getClusterRebalanceDecision() returns null, then the result of this method is meaningless, as no rebalance decision was taken. If isDecisionTaken() returns false, then invoking this method will throw an IllegalStateException.

getClusterRebalanceDecision

@Nullable
public Decision getClusterRebalanceDecision()

Returns the decision for being allowed to rebalance the shard. Invoking this method will return null if canRemain() ()} returns false, which means the node is not allowed to remain on its current node, so the cluster is forced to attempt to move the shard to a different node, as opposed to attempting to rebalance the shard if a better cluster balance is possible by moving it. If isDecisionTaken() returns false, then invoking this method will throw an IllegalStateException.

getAllocationDecision

@Nullable
public AllocationDecision getAllocationDecision()

Returns the AllocationDecision for moving this shard to another node. If isDecisionTaken() returns false, then invoking this method will throw an IllegalStateException.

getCurrentNodeRanking

public int getCurrentNodeRanking()

Gets the current ranking of the node to which the shard is currently assigned, relative to the other nodes in the cluster as reported in NodeAllocationResult.getWeightRanking(). The ranking will only return a meaningful positive integer if getClusterRebalanceDecision() returns a non-null value; otherwise, 0 will be returned. If isDecisionTaken() returns false, then invoking this method will throw an IllegalStateException.

getExplanation

public java.lang.String getExplanation()

Description copied from class: AbstractAllocationDecision

Gets the explanation for the decision. If AbstractAllocationDecision.isDecisionTaken() returns false, then invoking this method will throw an IllegalStateException.

Specified by:

getExplanation in class AbstractAllocationDecision

toXContent

public XContentBuilder toXContent(XContentBuilder builder,
                                  ToXContent.Params params)
                           throws java.io.IOException

Throws:

java.io.IOException

equals

public boolean equals(java.lang.Object other)

Overrides:

equals in class AbstractAllocationDecision

hashCode

public int hashCode()

Overrides:

hashCode in class AbstractAllocationDecision