org.opendaylight.controller.cluster.datastore.policy

Class TwoNodeClusterRaftPolicy

java.lang.Object

org.opendaylight.controller.cluster.datastore.policy.TwoNodeClusterRaftPolicy

All Implemented Interfaces:

RaftPolicy

public class TwoNodeClusterRaftPolicy
extends Object
implements RaftPolicy

The TwoNodeClusterRaftPolicy is intended to be used in a two node deployment where when one instance of the controller goes down the other instance is to take over and move the state forward. When a TwoNodeClusterRaftPolicy is used Raft elections are disabled. This is primarily because we would need to specify the leader externally. Also since we want one node to continue to function while the other node is down we would need to apply a modification to the state before consensus occurs.

Constructor Summary

Constructors

Constructor and Description
TwoNodeClusterRaftPolicy()

Method Summary

Modifier and Type	Method and Description
boolean	applyModificationToStateBeforeConsensus() According to Raft consensus on a Raft entry is achieved only after a Leader replicates a log entry to a majority of it's followers.
boolean	automaticElectionsEnabled() According to Raft a Follower which does not receive a heartbeat (aka AppendEntries) in a given period should become a Candidate and trigger an election.

Methods inherited from class java.lang.Object

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

Constructor Detail

TwoNodeClusterRaftPolicy

public TwoNodeClusterRaftPolicy()

Method Detail

automaticElectionsEnabled

public boolean automaticElectionsEnabled()

Description copied from interface: RaftPolicy

According to Raft a Follower which does not receive a heartbeat (aka AppendEntries) in a given period should become a Candidate and trigger an election.

Specified by:

automaticElectionsEnabled in interface RaftPolicy

Returns:

true to enable automatic Raft elections, false to disable them

applyModificationToStateBeforeConsensus

public boolean applyModificationToStateBeforeConsensus()

Description copied from interface: RaftPolicy

According to Raft consensus on a Raft entry is achieved only after a Leader replicates a log entry to a majority of it's followers.

Specified by:

applyModificationToStateBeforeConsensus in interface RaftPolicy

Returns:

true if modification should be applied before consensus, false to apply modification to state as per Raft