X-Git-Url: https://git.opendaylight.org/gerrit/gitweb?p=controller.git;a=blobdiff_plain;f=opendaylight%2Fmd-sal%2Fsal-akka-raft%2Fsrc%2Fmain%2Fjava%2Forg%2Fopendaylight%2Fcontroller%2Fcluster%2Fraft%2Fbehaviors%2FCandidate.java;h=569f6b3d245fe5a6c1021f0537f08b3e1ec36f6e;hp=74bede171f1f6e6ad6b33feef6806d3c77321581;hb=73ab61a037dd2489600acbc1eaf6f9ee549c204a;hpb=412db94945c5db5d2da918f5e23bd3abcecc4d10 diff --git a/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/Candidate.java b/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/Candidate.java index 74bede171f..569f6b3d24 100644 --- a/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/Candidate.java +++ b/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/Candidate.java @@ -5,24 +5,29 @@ * terms of the Eclipse Public License v1.0 which accompanies this distribution, * and is available at http://www.eclipse.org/legal/epl-v10.html */ - package org.opendaylight.controller.cluster.raft.behaviors; import akka.actor.ActorRef; import akka.actor.ActorSelection; -import java.util.Set; +import java.util.ArrayList; +import java.util.Collection; +import org.opendaylight.controller.cluster.raft.PeerInfo; import org.opendaylight.controller.cluster.raft.RaftActorContext; import org.opendaylight.controller.cluster.raft.RaftState; +import org.opendaylight.controller.cluster.raft.ReplicatedLogEntry; +import org.opendaylight.controller.cluster.raft.base.messages.ApplyState; import org.opendaylight.controller.cluster.raft.base.messages.ElectionTimeout; import org.opendaylight.controller.cluster.raft.messages.AppendEntries; import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply; import org.opendaylight.controller.cluster.raft.messages.RaftRPC; import org.opendaylight.controller.cluster.raft.messages.RequestVote; import org.opendaylight.controller.cluster.raft.messages.RequestVoteReply; +import scala.concurrent.duration.FiniteDuration; /** - * The behavior of a RaftActor when it is in the CandidateState - *

+ * The behavior of a RaftActor when it is in the Candidate raft state. + * + *

* Candidates (§5.2): *

*/ -public class Candidate extends AbstractRaftActorBehavior { +public final class Candidate extends AbstractRaftActorBehavior { private int voteCount; private final int votesRequired; - private final Set peers; + private final Collection votingPeers = new ArrayList<>(); - public Candidate(RaftActorContext context) { + public Candidate(final RaftActorContext context) { super(context, RaftState.Candidate); - peers = context.getPeerAddresses().keySet(); - - if(LOG.isDebugEnabled()) { - LOG.debug("{}: Election: Candidate has following peers: {}", logName(), peers); + for (PeerInfo peer: context.getPeers()) { + if (peer.isVoting()) { + votingPeers.add(peer.getId()); + } } - votesRequired = getMajorityVoteCount(peers.size()); + log.debug("{}: Election: Candidate has following voting peers: {}", logName(), votingPeers); + + votesRequired = getMajorityVoteCount(votingPeers.size()); startNewTerm(); - if(context.getPeerAddresses().isEmpty()){ - actor().tell(ELECTION_TIMEOUT, actor()); + if (votingPeers.isEmpty()) { + actor().tell(ElectionTimeout.INSTANCE, actor()); } else { scheduleElection(electionDuration()); } + } + @Override + public String getLeaderId() { + return null; + } + @Override + public short getLeaderPayloadVersion() { + return -1; } - @Override protected RaftActorBehavior handleAppendEntries(ActorRef sender, - AppendEntries appendEntries) { + @Override + protected RaftActorBehavior handleAppendEntries(final ActorRef sender, final AppendEntries appendEntries) { + + log.debug("{}: handleAppendEntries: {}", logName(), appendEntries); + + // Some other candidate for the same term became a leader and sent us an append entry + if (currentTerm() == appendEntries.getTerm()) { + log.info("{}: New Leader {} sent an AppendEntries to Candidate for term {} - will switch to Follower", + logName(), appendEntries.getLeaderId(), currentTerm()); - if(LOG.isDebugEnabled()) { - LOG.debug("{}: handleAppendEntries: {}", logName(), appendEntries); + return switchBehavior(new Follower(context)); } return this; } - @Override protected RaftActorBehavior handleAppendEntriesReply(ActorRef sender, - AppendEntriesReply appendEntriesReply) { - + @Override + protected RaftActorBehavior handleAppendEntriesReply(final ActorRef sender, + final AppendEntriesReply appendEntriesReply) { return this; } - @Override protected RaftActorBehavior handleRequestVoteReply(ActorRef sender, - RequestVoteReply requestVoteReply) { - - LOG.debug("{}: handleRequestVoteReply: {}, current voteCount: {}", logName(), requestVoteReply, - voteCount); + @Override + protected RaftActorBehavior handleRequestVoteReply(final ActorRef sender, final RequestVoteReply requestVoteReply) { + log.debug("{}: handleRequestVoteReply: {}, current voteCount: {}", logName(), requestVoteReply, voteCount); if (requestVoteReply.isVoteGranted()) { voteCount++; } if (voteCount >= votesRequired) { - return switchBehavior(new Leader(context)); + if (context.getLastApplied() < context.getReplicatedLog().lastIndex()) { + log.info("{}: LastApplied index {} is behind last index {} - switching to PreLeader", + logName(), context.getLastApplied(), context.getReplicatedLog().lastIndex()); + return internalSwitchBehavior(RaftState.PreLeader); + } else { + return internalSwitchBehavior(RaftState.Leader); + } } return this; } @Override - public RaftActorBehavior handleMessage(ActorRef sender, Object originalMessage) { - - Object message = fromSerializableMessage(originalMessage); - - if (message instanceof RaftRPC) { - - RaftRPC rpc = (RaftRPC) message; - - if(LOG.isDebugEnabled()) { - LOG.debug("{}: RaftRPC message received {}, my term is {}", logName(), rpc, - context.getTermInformation().getCurrentTerm()); - } + protected FiniteDuration electionDuration() { + return super.electionDuration().$div(context.getConfigParams().getCandidateElectionTimeoutDivisor()); + } - // If RPC request or response contains term T > currentTerm: - // set currentTerm = T, convert to follower (§5.1) - // This applies to all RPC messages and responses - if (rpc.getTerm() > context.getTermInformation().getCurrentTerm()) { - context.getTermInformation().updateAndPersist(rpc.getTerm(), null); - return switchBehavior(new Follower(context)); - } - } + @Override + ApplyState getApplyStateFor(final ReplicatedLogEntry entry) { + throw new IllegalStateException("A candidate should never attempt to apply " + entry); + } + @Override + public RaftActorBehavior handleMessage(final ActorRef sender, final Object message) { if (message instanceof ElectionTimeout) { - LOG.debug("{}: Received ElectionTimeout", logName()); + log.debug("{}: Received ElectionTimeout", logName()); if (votesRequired == 0) { // If there are no peers then we should be a Leader @@ -135,20 +149,44 @@ public class Candidate extends AbstractRaftActorBehavior { // who we do not know about (as a peer) // to send a message to the candidate - return switchBehavior(new Leader(context)); + return internalSwitchBehavior(RaftState.Leader); } + startNewTerm(); scheduleElection(electionDuration()); return this; } - return super.handleMessage(sender, message); - } + if (message instanceof RaftRPC) { + RaftRPC rpc = (RaftRPC) message; - private void startNewTerm() { + log.debug("{}: RaftRPC message received {}, my term is {}", logName(), rpc, + context.getTermInformation().getCurrentTerm()); + // If RPC request or response contains term T > currentTerm: + // set currentTerm = T, convert to follower (§5.1) + // This applies to all RPC messages and responses + if (rpc.getTerm() > context.getTermInformation().getCurrentTerm()) { + log.info("{}: Term {} in \"{}\" message is greater than Candidate's term {} - switching to Follower", + logName(), rpc.getTerm(), rpc, context.getTermInformation().getCurrentTerm()); + + context.getTermInformation().updateAndPersist(rpc.getTerm(), null); + + // The raft paper does not say whether or not a Candidate can/should process a RequestVote in + // this case but doing so gains quicker convergence when the sender's log is more up-to-date. + if (message instanceof RequestVote) { + super.handleMessage(sender, message); + } + + return internalSwitchBehavior(RaftState.Follower); + } + } + return super.handleMessage(sender, message); + } + + private void startNewTerm() { // set voteCount back to 1 (that is voting for self) voteCount = 1; @@ -157,28 +195,29 @@ public class Candidate extends AbstractRaftActorBehavior { long newTerm = currentTerm + 1; context.getTermInformation().updateAndPersist(newTerm, context.getId()); - LOG.debug("{}: Starting new term {}", logName(), newTerm); + log.info("{}: Starting new election term {}", logName(), newTerm); // Request for a vote // TODO: Retry request for vote if replies do not arrive in a reasonable // amount of time TBD - for (String peerId : peers) { + for (String peerId : votingPeers) { ActorSelection peerActor = context.getPeerActorSelection(peerId); - if(peerActor != null) { + if (peerActor != null) { RequestVote requestVote = new RequestVote( context.getTermInformation().getCurrentTerm(), context.getId(), context.getReplicatedLog().lastIndex(), context.getReplicatedLog().lastTerm()); - LOG.debug("{}: Sending {} to peer {}", logName(), requestVote, peerId); + log.debug("{}: Sending {} to peer {}", logName(), requestVote, peerId); peerActor.tell(requestVote, context.getActor()); } } } - @Override public void close() throws Exception { + @Override + public void close() { stopElection(); } }