Module org.elasticsearch.server

Package org.elasticsearch.cluster.coordination

Class ElectionStrategy

java.lang.Object

org.elasticsearch.cluster.coordination.ElectionStrategy

public abstract class ElectionStrategy
extends Object

Allows plugging in a custom election strategy, restricting the notion of an election quorum. Custom additional quorum restrictions can be defined by implementing the satisfiesAdditionalQuorumConstraints(org.elasticsearch.cluster.node.DiscoveryNode, long, long, long, org.elasticsearch.cluster.coordination.CoordinationMetadata.VotingConfiguration, org.elasticsearch.cluster.coordination.CoordinationMetadata.VotingConfiguration, org.elasticsearch.cluster.coordination.CoordinationState.VoteCollection) method.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final record	ElectionStrategy.NodeEligibility	Contains a result for whether a node may win an election and the reason if not.

Field Summary

Fields

Modifier and Type	Field	Description
static final ElectionStrategy	DEFAULT_INSTANCE
static final ElectionStrategy.NodeEligibility	NODE_MAY_NOT_WIN_ELECTION
static final ElectionStrategy.NodeEligibility	NODE_MAY_WIN_ELECTION

Constructor Summary

Constructors

Constructor	Description
ElectionStrategy()

Method Summary

Modifier and Type	Method	Description
void	beforeCommit(long term, long version, ActionListener<Void> listener)
boolean	isElectionQuorum(DiscoveryNode localNode, long localCurrentTerm, long localAcceptedTerm, long localAcceptedVersion, CoordinationMetadata.VotingConfiguration lastCommittedConfiguration, CoordinationMetadata.VotingConfiguration lastAcceptedConfiguration, CoordinationState.VoteCollection joinVotes)	Whether there is an election quorum from the point of view of the given local node under the provided voting configurations
boolean	isInvalidReconfiguration(ClusterState clusterState, CoordinationMetadata.VotingConfiguration lastAcceptedConfiguration, CoordinationMetadata.VotingConfiguration lastCommittedConfiguration)
boolean	isPublishQuorum(CoordinationState.VoteCollection voteCollection, CoordinationMetadata.VotingConfiguration lastCommittedConfiguration, CoordinationMetadata.VotingConfiguration latestPublishedConfiguration)
ElectionStrategy.NodeEligibility	nodeMayWinElection(ClusterState lastAcceptedState, DiscoveryNode node)
void	onNewElection(DiscoveryNode candidateMasterNode, long proposedTerm, ActionListener<StartJoinRequest> listener)
protected abstract boolean	satisfiesAdditionalQuorumConstraints(DiscoveryNode localNode, long localCurrentTerm, long localAcceptedTerm, long localAcceptedVersion, CoordinationMetadata.VotingConfiguration lastCommittedConfiguration, CoordinationMetadata.VotingConfiguration lastAcceptedConfiguration, CoordinationState.VoteCollection joinVotes)	The extension point to be overridden by plugins.

Methods inherited from class java.lang.Object

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

Field Details

DEFAULT_INSTANCE

public static final ElectionStrategy DEFAULT_INSTANCE

NODE_MAY_WIN_ELECTION

public static final ElectionStrategy.NodeEligibility NODE_MAY_WIN_ELECTION

NODE_MAY_NOT_WIN_ELECTION

public static final ElectionStrategy.NodeEligibility NODE_MAY_NOT_WIN_ELECTION

Constructor Details

ElectionStrategy

public ElectionStrategy()

Method Details

isElectionQuorum

public boolean isElectionQuorum(DiscoveryNode localNode,
 long localCurrentTerm,
 long localAcceptedTerm,
 long localAcceptedVersion,
 CoordinationMetadata.VotingConfiguration lastCommittedConfiguration,
 CoordinationMetadata.VotingConfiguration lastAcceptedConfiguration,
 CoordinationState.VoteCollection joinVotes)

Whether there is an election quorum from the point of view of the given local node under the provided voting configurations

isPublishQuorum

public boolean isPublishQuorum(CoordinationState.VoteCollection voteCollection,
 CoordinationMetadata.VotingConfiguration lastCommittedConfiguration,
 CoordinationMetadata.VotingConfiguration latestPublishedConfiguration)

satisfiesAdditionalQuorumConstraints

protected abstract boolean satisfiesAdditionalQuorumConstraints(DiscoveryNode localNode,
 long localCurrentTerm,
 long localAcceptedTerm,
 long localAcceptedVersion,
 CoordinationMetadata.VotingConfiguration lastCommittedConfiguration,
 CoordinationMetadata.VotingConfiguration lastAcceptedConfiguration,
 CoordinationState.VoteCollection joinVotes)

The extension point to be overridden by plugins. Defines additional constraints on the election quorum.

Parameters:

localNode - the local node for the election quorum

localCurrentTerm - the current term of the local node

localAcceptedTerm - the last accepted term of the local node

localAcceptedVersion - the last accepted version of the local node

lastCommittedConfiguration - the last committed configuration for the election quorum

lastAcceptedConfiguration - the last accepted configuration for the election quorum

joinVotes - the votes that were provided so far

Returns:

true iff the additional quorum constraints are satisfied

onNewElection

public void onNewElection(DiscoveryNode candidateMasterNode,
 long proposedTerm,
 ActionListener<StartJoinRequest> listener)

isInvalidReconfiguration

public boolean isInvalidReconfiguration(ClusterState clusterState,
 CoordinationMetadata.VotingConfiguration lastAcceptedConfiguration,
 CoordinationMetadata.VotingConfiguration lastCommittedConfiguration)

beforeCommit

public void beforeCommit(long term,
 long version,
 ActionListener<Void> listener)

nodeMayWinElection

public ElectionStrategy.NodeEligibility nodeMayWinElection(ClusterState lastAcceptedState,
 DiscoveryNode node)