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%2FLeader.java;h=2a44e8b7a5c3adeecd1c534de0664d8deb290934;hp=ec4551ac4ffb7cae84c9ce9fd82a652499017d98;hb=475d28f717bae92b2cc10b0589131771fcc62242;hpb=53e9fc9521e5fc0d49e9b1cb8763f8508101984b diff --git a/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/Leader.java b/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/Leader.java index ec4551ac4f..2a44e8b7a5 100644 --- a/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/Leader.java +++ b/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/Leader.java @@ -19,18 +19,24 @@ import org.opendaylight.controller.cluster.raft.FollowerLogInformationImpl; 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.internal.messages.ApplyState; -import org.opendaylight.controller.cluster.raft.internal.messages.Replicate; -import org.opendaylight.controller.cluster.raft.internal.messages.SendHeartBeat; +import org.opendaylight.controller.cluster.raft.base.messages.ApplyState; +import org.opendaylight.controller.cluster.raft.base.messages.Replicate; +import org.opendaylight.controller.cluster.raft.base.messages.SendHeartBeat; +import org.opendaylight.controller.cluster.raft.base.messages.SendInstallSnapshot; import org.opendaylight.controller.cluster.raft.messages.AppendEntries; import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply; +import org.opendaylight.controller.cluster.raft.messages.InstallSnapshot; +import org.opendaylight.controller.cluster.raft.messages.InstallSnapshotReply; +import org.opendaylight.controller.cluster.raft.messages.RaftRPC; import org.opendaylight.controller.cluster.raft.messages.RequestVoteReply; import scala.concurrent.duration.FiniteDuration; import java.util.ArrayList; +import java.util.Collections; import java.util.HashMap; import java.util.List; import java.util.Map; +import java.util.Set; import java.util.concurrent.TimeUnit; import java.util.concurrent.atomic.AtomicLong; @@ -62,9 +68,11 @@ public class Leader extends AbstractRaftActorBehavior { private final Map followerToLog = new HashMap(); - private final Map followerToActor = new HashMap<>(); + private final Set followers; - private Cancellable heartbeatCancel = null; + private Cancellable heartbeatSchedule = null; + private Cancellable appendEntriesSchedule = null; + private Cancellable installSnapshotSchedule = null; private List trackerList = new ArrayList<>(); @@ -77,21 +85,21 @@ public class Leader extends AbstractRaftActorBehavior { context.setCommitIndex(lastIndex()); } - for (String followerId : context.getPeerAddresses().keySet()) { + followers = context.getPeerAddresses().keySet(); + + for (String followerId : followers) { FollowerLogInformation followerLogInformation = new FollowerLogInformationImpl(followerId, new AtomicLong(lastIndex()), new AtomicLong(-1)); - followerToActor.put(followerId, - context.actorSelection(context.getPeerAddress(followerId))); - followerToLog.put(followerId, followerLogInformation); - } - if (followerToActor.size() > 0) { - minReplicationCount = (followerToActor.size() + 1) / 2 + 1; + context.getLogger().debug("Election:Leader has following peers:"+ followers); + + if (followers.size() > 0) { + minReplicationCount = (followers.size() + 1) / 2 + 1; } else { minReplicationCount = 0; } @@ -103,35 +111,52 @@ public class Leader extends AbstractRaftActorBehavior { // prevent election timeouts (§5.2) scheduleHeartBeat(new FiniteDuration(0, TimeUnit.SECONDS)); + scheduleInstallSnapshotCheck( + new FiniteDuration(context.getConfigParams().getHeartBeatInterval().length() * 1000, + context.getConfigParams().getHeartBeatInterval().unit()) + ); } @Override protected RaftState handleAppendEntries(ActorRef sender, - AppendEntries appendEntries, RaftState suggestedState) { + AppendEntries appendEntries) { - context.getLogger() - .error("An unexpected AppendEntries received in state " + state()); + context.getLogger().info("Leader: Received {}", appendEntries.toString()); - return suggestedState; + return state(); } @Override protected RaftState handleAppendEntriesReply(ActorRef sender, - AppendEntriesReply appendEntriesReply, RaftState suggestedState) { + AppendEntriesReply appendEntriesReply) { - // Do not take any other action since a behavior change is coming - if (suggestedState != state()) - return suggestedState; + if(! appendEntriesReply.isSuccess()) { + context.getLogger() + .info("Leader: Received {}", appendEntriesReply.toString()); + } // Update the FollowerLogInformation String followerId = appendEntriesReply.getFollowerId(); FollowerLogInformation followerLogInformation = followerToLog.get(followerId); + + if(followerLogInformation == null){ + context.getLogger().error("Unknown follower {}", followerId); + return state(); + } + if (appendEntriesReply.isSuccess()) { followerLogInformation .setMatchIndex(appendEntriesReply.getLogLastIndex()); followerLogInformation .setNextIndex(appendEntriesReply.getLogLastIndex() + 1); } else { + + // TODO: When we find that the follower is out of sync with the + // Leader we simply decrement that followers next index by 1. + // Would it be possible to do better than this? The RAFT spec + // does not explicitly deal with it but may be something for us to + // think about + followerLogInformation.decrNextIndex(); } @@ -166,7 +191,7 @@ public class Leader extends AbstractRaftActorBehavior { applyLogToStateMachine(context.getCommitIndex()); } - return suggestedState; + return state(); } protected ClientRequestTracker findClientRequestTracker(long logIndex) { @@ -180,36 +205,66 @@ public class Leader extends AbstractRaftActorBehavior { } @Override protected RaftState handleRequestVoteReply(ActorRef sender, - RequestVoteReply requestVoteReply, RaftState suggestedState) { - return suggestedState; + RequestVoteReply requestVoteReply) { + return state(); } @Override public RaftState state() { return RaftState.Leader; } - @Override public RaftState handleMessage(ActorRef sender, Object message) { + @Override public RaftState handleMessage(ActorRef sender, Object originalMessage) { Preconditions.checkNotNull(sender, "sender should not be null"); + Object message = fromSerializableMessage(originalMessage); + + if (message instanceof RaftRPC) { + RaftRPC rpc = (RaftRPC) message; + // 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 RaftState.Follower; + } + } + try { if (message instanceof SendHeartBeat) { return sendHeartBeat(); + } else if(message instanceof SendInstallSnapshot) { + installSnapshotIfNeeded(); } else if (message instanceof Replicate) { replicate((Replicate) message); + } else if (message instanceof InstallSnapshotReply){ + handleInstallSnapshotReply( + (InstallSnapshotReply) message); } } finally { - scheduleHeartBeat(HEART_BEAT_INTERVAL); + scheduleHeartBeat(context.getConfigParams().getHeartBeatInterval()); } return super.handleMessage(sender, message); } + private void handleInstallSnapshotReply(InstallSnapshotReply message) { + InstallSnapshotReply reply = message; + String followerId = reply.getFollowerId(); + FollowerLogInformation followerLogInformation = + followerToLog.get(followerId); + + followerLogInformation + .setMatchIndex(context.getReplicatedLog().getSnapshotIndex()); + followerLogInformation + .setNextIndex(context.getReplicatedLog().getSnapshotIndex() + 1); + } + private void replicate(Replicate replicate) { long logIndex = replicate.getReplicatedLogEntry().getIndex(); context.getLogger().debug("Replicate message " + logIndex); - if (followerToActor.size() == 0) { + if (followers.size() == 0) { context.setCommitIndex( replicate.getReplicatedLogEntry().getIndex()); @@ -235,43 +290,92 @@ public class Leader extends AbstractRaftActorBehavior { private void sendAppendEntries() { // Send an AppendEntries to all followers - for (String followerId : followerToActor.keySet()) { + for (String followerId : followers) { ActorSelection followerActor = - followerToActor.get(followerId); + context.getPeerActorSelection(followerId); - FollowerLogInformation followerLogInformation = - followerToLog.get(followerId); + if (followerActor != null) { + FollowerLogInformation followerLogInformation = + followerToLog.get(followerId); - long nextIndex = followerLogInformation.getNextIndex().get(); + long nextIndex = followerLogInformation.getNextIndex().get(); - List entries = - context.getReplicatedLog().getFrom(nextIndex); + List entries = Collections.emptyList(); - followerActor.tell( - new AppendEntries(currentTerm(), context.getId(), - prevLogIndex(nextIndex), prevLogTerm(nextIndex), - entries, context.getCommitIndex() - ), - actor() - ); + if (context.getReplicatedLog().isPresent(nextIndex)) { + // TODO: Instead of sending all entries from nextIndex + // only send a fixed number of entries to each follower + // This is to avoid the situation where there are a lot of + // entries to install for a fresh follower or to a follower + // that has fallen too far behind with the log but yet is not + // eligible to receive a snapshot + entries = + context.getReplicatedLog().getFrom(nextIndex); + } + + followerActor.tell( + new AppendEntries(currentTerm(), context.getId(), + prevLogIndex(nextIndex), + prevLogTerm(nextIndex), entries, + context.getCommitIndex()).toSerializable(), + actor() + ); + } + } + } + + /** + * An installSnapshot is scheduled at a interval that is a multiple of + * a HEARTBEAT_INTERVAL. This is to avoid the need to check for installing + * snapshots at every heartbeat. + */ + private void installSnapshotIfNeeded(){ + for (String followerId : followers) { + ActorSelection followerActor = + context.getPeerActorSelection(followerId); + + if(followerActor != null) { + FollowerLogInformation followerLogInformation = + followerToLog.get(followerId); + + long nextIndex = followerLogInformation.getNextIndex().get(); + + if (!context.getReplicatedLog().isPresent(nextIndex) && context + .getReplicatedLog().isInSnapshot(nextIndex)) { + followerActor.tell( + new InstallSnapshot(currentTerm(), context.getId(), + context.getReplicatedLog().getSnapshotIndex(), + context.getReplicatedLog().getSnapshotTerm(), + context.getReplicatedLog().getSnapshot() + ), + actor() + ); + } + } } } private RaftState sendHeartBeat() { - if (followerToActor.size() > 0) { + if (followers.size() > 0) { sendAppendEntries(); } return state(); } private void stopHeartBeat() { - if (heartbeatCancel != null && !heartbeatCancel.isCancelled()) { - heartbeatCancel.cancel(); + if (heartbeatSchedule != null && !heartbeatSchedule.isCancelled()) { + heartbeatSchedule.cancel(); + } + } + + private void stopInstallSnapshotSchedule() { + if (installSnapshotSchedule != null && !installSnapshotSchedule.isCancelled()) { + installSnapshotSchedule.cancel(); } } private void scheduleHeartBeat(FiniteDuration interval) { - if(followerToActor.keySet().size() == 0){ + if(followers.size() == 0){ // Optimization - do not bother scheduling a heartbeat as there are // no followers return; @@ -284,13 +388,34 @@ public class Leader extends AbstractRaftActorBehavior { // Scheduling the heartbeat only once here because heartbeats do not // need to be sent if there are other messages being sent to the remote // actor. - heartbeatCancel = + heartbeatSchedule = context.getActorSystem().scheduler().scheduleOnce( interval, context.getActor(), new SendHeartBeat(), context.getActorSystem().dispatcher(), context.getActor()); } + + private void scheduleInstallSnapshotCheck(FiniteDuration interval) { + if(followers.size() == 0){ + // Optimization - do not bother scheduling a heartbeat as there are + // no followers + return; + } + + stopInstallSnapshotSchedule(); + + // Schedule a message to send append entries to followers that can + // accept an append entries with some data in it + installSnapshotSchedule = + context.getActorSystem().scheduler().scheduleOnce( + interval, + context.getActor(), new SendInstallSnapshot(), + context.getActorSystem().dispatcher(), context.getActor()); + } + + + @Override public void close() throws Exception { stopHeartBeat(); }