package org.opendaylight.controller.cluster.raft.behaviors;
import akka.actor.ActorRef;
-import akka.actor.ActorSelection;
import akka.actor.Cancellable;
+import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
-import org.opendaylight.controller.cluster.raft.ClientRequestTracker;
-import org.opendaylight.controller.cluster.raft.ClientRequestTrackerImpl;
-import org.opendaylight.controller.cluster.raft.FollowerLogInformation;
-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.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 org.opendaylight.controller.cluster.raft.base.messages.InitiateInstallSnapshot;
+import org.opendaylight.controller.cluster.raft.base.messages.IsolatedLeaderCheck;
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;
-
/**
* The behavior of a RaftActor when it is in the Leader state
* <p/>
* of matchIndex[i] ≥ N, and log[N].term == currentTerm:
* set commitIndex = N (§5.3, §5.4).
*/
-public class Leader extends AbstractRaftActorBehavior {
-
-
- private final Map<String, FollowerLogInformation> followerToLog =
- new HashMap();
-
- private final Set<String> followers;
-
- private Cancellable heartbeatSchedule = null;
- private Cancellable appendEntriesSchedule = null;
+public class Leader extends AbstractLeader {
private Cancellable installSnapshotSchedule = null;
-
- private List<ClientRequestTracker> trackerList = new ArrayList<>();
-
- private final int minReplicationCount;
+ private Cancellable isolatedLeaderCheckSchedule = null;
public Leader(RaftActorContext context) {
super(context);
- if (lastIndex() >= 0) {
- context.setCommitIndex(lastIndex());
- }
-
- followers = context.getPeerAddresses().keySet();
-
- for (String followerId : followers) {
- FollowerLogInformation followerLogInformation =
- new FollowerLogInformationImpl(followerId,
- new AtomicLong(lastIndex()),
- new AtomicLong(-1));
-
- followerToLog.put(followerId, followerLogInformation);
- }
-
- context.getLogger().debug("Election:Leader has following peers:"+ followers);
-
- if (followers.size() > 0) {
- minReplicationCount = (followers.size() + 1) / 2 + 1;
- } else {
- minReplicationCount = 0;
- }
-
-
- // Immediately schedule a heartbeat
- // Upon election: send initial empty AppendEntries RPCs
- // (heartbeat) to each server; repeat during idle periods to
- // 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) {
-
- context.getLogger().info("Leader: Received {}", appendEntries.toString());
-
- return state();
- }
-
- @Override protected RaftState handleAppendEntriesReply(ActorRef sender,
- AppendEntriesReply appendEntriesReply) {
-
- 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();
- }
-
- // Now figure out if this reply warrants a change in the commitIndex
- // If there exists an N such that N > commitIndex, a majority
- // of matchIndex[i] ≥ N, and log[N].term == currentTerm:
- // set commitIndex = N (§5.3, §5.4).
- for (long N = context.getCommitIndex() + 1; ; N++) {
- int replicatedCount = 1;
-
- for (FollowerLogInformation info : followerToLog.values()) {
- if (info.getMatchIndex().get() >= N) {
- replicatedCount++;
- }
- }
-
- if (replicatedCount >= minReplicationCount) {
- ReplicatedLogEntry replicatedLogEntry =
- context.getReplicatedLog().get(N);
- if (replicatedLogEntry != null
- && replicatedLogEntry.getTerm()
- == currentTerm()) {
- context.setCommitIndex(N);
- }
- } else {
- break;
- }
- }
-
- // Apply the change to the state machine
- if (context.getCommitIndex() > context.getLastApplied()) {
- applyLogToStateMachine(context.getCommitIndex());
- }
+ scheduleInstallSnapshotCheck(context.getConfigParams().getIsolatedCheckInterval());
- return state();
+ scheduleIsolatedLeaderCheck(
+ new FiniteDuration(context.getConfigParams().getHeartBeatInterval().length() * 10,
+ context.getConfigParams().getHeartBeatInterval().unit()));
}
- protected ClientRequestTracker findClientRequestTracker(long logIndex) {
- for (ClientRequestTracker tracker : trackerList) {
- if (tracker.getIndex() == logIndex) {
- return tracker;
- }
- }
-
- return null;
- }
-
- @Override protected RaftState handleRequestVoteReply(ActorRef sender,
- RequestVoteReply requestVoteReply) {
- return state();
- }
-
- @Override public RaftState state() {
- return RaftState.Leader;
- }
-
- @Override public RaftState handleMessage(ActorRef sender, Object originalMessage) {
+ @Override public RaftActorBehavior 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;
+ if (originalMessage instanceof IsolatedLeaderCheck) {
+ if (isLeaderIsolated()) {
+ LOG.info("At least {} followers need to be active, Switching {} from Leader to IsolatedLeader",
+ minIsolatedLeaderPeerCount, leaderId);
+ return switchBehavior(new IsolatedLeader(context));
}
}
- 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(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);
-
- // Create a tracker entry we will use this later to notify the
- // client actor
- trackerList.add(
- new ClientRequestTrackerImpl(replicate.getClientActor(),
- replicate.getIdentifier(),
- logIndex)
- );
-
- if (followers.size() == 0) {
- context.setCommitIndex(logIndex);
- applyLogToStateMachine(logIndex);
- } else {
- sendAppendEntries();
- }
- }
-
- private void sendAppendEntries() {
- // Send an AppendEntries to all followers
- for (String followerId : followers) {
- ActorSelection followerActor =
- context.getPeerActorSelection(followerId);
-
- if (followerActor != null) {
- FollowerLogInformation followerLogInformation =
- followerToLog.get(followerId);
-
- long nextIndex = followerLogInformation.getNextIndex().get();
-
- List<ReplicatedLogEntry> entries = Collections.emptyList();
-
- 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, 1);
- }
-
- 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()
- );
- }
- }
- }
+ return super.handleMessage(sender, originalMessage);
}
- private RaftState sendHeartBeat() {
- if (followers.size() > 0) {
- sendAppendEntries();
- }
- return state();
- }
-
- private void stopHeartBeat() {
- if (heartbeatSchedule != null && !heartbeatSchedule.isCancelled()) {
- heartbeatSchedule.cancel();
- }
- }
-
- private void stopInstallSnapshotSchedule() {
+ protected void stopInstallSnapshotSchedule() {
if (installSnapshotSchedule != null && !installSnapshotSchedule.isCancelled()) {
installSnapshotSchedule.cancel();
}
}
- private void scheduleHeartBeat(FiniteDuration interval) {
- if(followers.size() == 0){
- // Optimization - do not bother scheduling a heartbeat as there are
- // no followers
- return;
- }
-
- stopHeartBeat();
-
- // Schedule a heartbeat. When the scheduler triggers a SendHeartbeat
- // message is sent to itself.
- // 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.
- heartbeatSchedule =
- context.getActorSystem().scheduler().scheduleOnce(
- interval,
- context.getActor(), new SendHeartBeat(),
- context.getActorSystem().dispatcher(), context.getActor());
- }
-
-
- private void scheduleInstallSnapshotCheck(FiniteDuration interval) {
+ protected void scheduleInstallSnapshotCheck(FiniteDuration interval) {
if(followers.size() == 0){
// Optimization - do not bother scheduling a heartbeat as there are
// no followers
installSnapshotSchedule =
context.getActorSystem().scheduler().scheduleOnce(
interval,
- context.getActor(), new SendInstallSnapshot(),
+ context.getActor(), new InitiateInstallSnapshot(),
context.getActorSystem().dispatcher(), context.getActor());
}
+ protected void stopIsolatedLeaderCheckSchedule() {
+ if (isolatedLeaderCheckSchedule != null && !isolatedLeaderCheckSchedule.isCancelled()) {
+ isolatedLeaderCheckSchedule.cancel();
+ }
+ }
+ protected void scheduleIsolatedLeaderCheck(FiniteDuration isolatedCheckInterval) {
+ isolatedLeaderCheckSchedule = context.getActorSystem().scheduler().schedule(isolatedCheckInterval, isolatedCheckInterval,
+ context.getActor(), new IsolatedLeaderCheck(),
+ context.getActorSystem().dispatcher(), context.getActor());
+ }
@Override public void close() throws Exception {
- stopHeartBeat();
+ stopInstallSnapshotSchedule();
+ stopIsolatedLeaderCheckSchedule();
+ super.close();
}
- @Override public String getLeaderId() {
- return context.getId();
+ @VisibleForTesting
+ void markFollowerActive(String followerId) {
+ followerToLog.get(followerId).markFollowerActive();
}
-
}
Code Review / controller.git / blobdiff