import akka.actor.ActorRef;
import akka.japi.Procedure;
import com.google.common.annotations.VisibleForTesting;
-import com.google.common.base.Preconditions;
+import com.google.common.base.Stopwatch;
import java.util.ArrayList;
+import java.util.concurrent.TimeUnit;
+import javax.annotation.Nullable;
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.ServerConfigurationPayload;
import org.opendaylight.controller.cluster.raft.Snapshot;
import org.opendaylight.controller.cluster.raft.base.messages.ApplySnapshot;
import org.opendaylight.controller.cluster.raft.base.messages.ElectionTimeout;
+import org.opendaylight.controller.cluster.raft.base.messages.TimeoutNow;
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.RaftRPC;
import org.opendaylight.controller.cluster.raft.messages.RequestVote;
import org.opendaylight.controller.cluster.raft.messages.RequestVoteReply;
+import org.opendaylight.controller.cluster.raft.persisted.ServerConfigurationPayload;
/**
* The behavior of a RaftActor in the Follower state
}
};
+ private final Stopwatch lastLeaderMessageTimer = Stopwatch.createUnstarted();
private SnapshotTracker snapshotTracker = null;
private String leaderId;
private short leaderPayloadVersion;
initialSyncStatusTracker = new SyncStatusTracker(context.getActor(), getId(), SYNC_THRESHOLD);
- if(canStartElection()) {
- if (context.getPeerIds().isEmpty() && getLeaderId() == null) {
- actor().tell(ElectionTimeout.INSTANCE, actor());
- } else {
- scheduleElection(electionDuration());
- }
+ if (context.getPeerIds().isEmpty() && getLeaderId() == null) {
+ actor().tell(TimeoutNow.INSTANCE, actor());
+ } else {
+ scheduleElection(electionDuration());
}
}
}
@VisibleForTesting
- protected final void setLeaderId(final String leaderId) {
- this.leaderId = Preconditions.checkNotNull(leaderId);
+ protected final void setLeaderId(@Nullable final String leaderId) {
+ this.leaderId = leaderId;
}
@Override
this.leaderPayloadVersion = leaderPayloadVersion;
}
- private boolean isLogEntryPresent(long index){
- if(index == context.getReplicatedLog().getSnapshotIndex()){
- return true;
+ private void restartLastLeaderMessageTimer() {
+ if (lastLeaderMessageTimer.isRunning()) {
+ lastLeaderMessageTimer.reset();
}
- ReplicatedLogEntry previousEntry = context.getReplicatedLog()
- .get(index);
-
- return previousEntry != null;
-
+ lastLeaderMessageTimer.start();
}
- private long getLogEntryTerm(long index){
- if(index == context.getReplicatedLog().getSnapshotIndex()){
- return context.getReplicatedLog().getSnapshotTerm();
+ private boolean isLogEntryPresent(long index){
+ if(context.getReplicatedLog().isInSnapshot(index)) {
+ return true;
}
- ReplicatedLogEntry previousEntry = context.getReplicatedLog()
- .get(index);
+ ReplicatedLogEntry entry = context.getReplicatedLog().get(index);
+ return entry != null;
- if(previousEntry != null){
- return previousEntry.getTerm();
- }
-
- return -1;
}
private void updateInitialSyncStatus(long currentLeaderCommit, String leaderId){
// Find the entry up until the one that is not in the follower's log
for (int i = 0;i < appendEntries.getEntries().size(); i++, addEntriesFrom++) {
ReplicatedLogEntry matchEntry = appendEntries.getEntries().get(i);
- ReplicatedLogEntry newEntry = context.getReplicatedLog().get(matchEntry.getIndex());
- if (newEntry == null) {
- //newEntry not found in the log
+ if(!isLogEntryPresent(matchEntry.getIndex())) {
+ // newEntry not found in the log
break;
}
- if (newEntry.getTerm() == matchEntry.getTerm()) {
+ long existingEntryTerm = getLogEntryTerm(matchEntry.getIndex());
+
+ LOG.debug("{}: matchEntry {} is present: existingEntryTerm: {}", logName(), matchEntry,
+ existingEntryTerm);
+
+ // existingEntryTerm == -1 means it's in the snapshot and not in the log. We don't know
+ // what the term was so we'll assume it matches.
+ if(existingEntryTerm == -1 || existingEntryTerm == matchEntry.getTerm()) {
continue;
}
matchEntry.getIndex());
// Entries do not match so remove all subsequent entries
- context.getReplicatedLog().removeFromAndPersist(matchEntry.getIndex());
+ if(!context.getReplicatedLog().removeFromAndPersist(matchEntry.getIndex())) {
+ // Could not remove the entries - this means the matchEntry index must be in the
+ // snapshot and not the log. In this case the prior entries are part of the state
+ // so we must send back a reply to force a snapshot to completely re-sync the
+ // follower's log and state.
+
+ LOG.debug("{}: Could not remove entries - sending reply to force snapshot", logName());
+ sender.tell(new AppendEntriesReply(context.getId(), currentTerm(), false, lastIndex,
+ lastTerm(), context.getPayloadVersion(), true), actor());
+ return this;
+ }
+
break;
} else {
sender.tell(new AppendEntriesReply(context.getId(), currentTerm(), false, lastIndex,
}
lastIndex = lastIndex();
- LOG.debug("{}: After cleanup entries to be added from = {}", logName(),
- (addEntriesFrom + lastIndex));
+ LOG.debug("{}: After cleanup, lastIndex: {}, entries to be added from: {}", logName(),
+ lastIndex, addEntriesFrom);
// 4. Append any new entries not already in the log
for (int i = addEntriesFrom; i < appendEntries.getEntries().size(); i++) {
// The follower's log is out of sync because the Leader's
// prevLogIndex entry was not found in it's log
- LOG.debug("{}: The log is not empty but the prevLogIndex {} was not found in it",
- logName(), appendEntries.getPrevLogIndex());
+ LOG.debug("{}: The log is not empty but the prevLogIndex {} was not found in it - lastIndex: {}, snapshotIndex: {}",
+ logName(), appendEntries.getPrevLogIndex(), lastIndex, context.getReplicatedLog().getSnapshotIndex());
} else if (lastIndex > -1 && prevEntryPresent && prevLogTerm != appendEntries.getPrevLogTerm()) {
// The follower's log is out of sync because the Leader's
logName(), prevLogTerm, appendEntries.getPrevLogTerm());
} else if(appendEntries.getPrevLogIndex() == -1 && appendEntries.getPrevLogTerm() == -1
&& appendEntries.getReplicatedToAllIndex() != -1
- && !isLogEntryPresent(appendEntries.getReplicatedToAllIndex())
- && !context.getReplicatedLog().isInSnapshot(appendEntries.getReplicatedToAllIndex())) {
+ && !isLogEntryPresent(appendEntries.getReplicatedToAllIndex())) {
// This append entry comes from a leader who has it's log aggressively trimmed and so does not have
// the previous entry in it's in-memory journal
logName(), appendEntries.getReplicatedToAllIndex());
} else if(appendEntries.getPrevLogIndex() == -1 && appendEntries.getPrevLogTerm() == -1
&& appendEntries.getReplicatedToAllIndex() != -1 && numLogEntries > 0
- && !isLogEntryPresent(appendEntries.getEntries().get(0).getIndex() - 1)
- && !context.getReplicatedLog().isInSnapshot(appendEntries.getEntries().get(0).getIndex() - 1)) {
+ && !isLogEntryPresent(appendEntries.getEntries().get(0).getIndex() - 1)) {
LOG.debug(
"{}: Cannot append entries because the calculated previousIndex {} was not found in the in-memory journal",
logName(), appendEntries.getEntries().get(0).getIndex() - 1);
@Override
public RaftActorBehavior handleMessage(ActorRef sender, Object originalMessage) {
+ if (originalMessage instanceof ElectionTimeout || originalMessage instanceof TimeoutNow) {
+ return handleElectionTimeout(originalMessage);
+ }
- Object message = fromSerializableMessage(originalMessage);
+ final Object message = fromSerializableMessage(originalMessage);
+ if (!(message instanceof RaftRPC)) {
+ // The rest of the processing requires the message to be a RaftRPC
+ return null;
+ }
- 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()) {
- LOG.debug("{}: Term {} in \"{}\" message is greater than follower's term {} - updating term",
- logName(), rpc.getTerm(), rpc, context.getTermInformation().getCurrentTerm());
+ final 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()) {
+ LOG.debug("{}: Term {} in \"{}\" message is greater than follower's term {} - updating term",
+ logName(), rpc.getTerm(), rpc, context.getTermInformation().getCurrentTerm());
- context.getTermInformation().updateAndPersist(rpc.getTerm(), null);
- }
+ context.getTermInformation().updateAndPersist(rpc.getTerm(), null);
+ }
+
+ if (rpc instanceof InstallSnapshot) {
+ handleInstallSnapshot(sender, (InstallSnapshot) rpc);
+ restartLastLeaderMessageTimer();
+ scheduleElection(electionDuration());
+ return this;
+ }
+
+ if (!(rpc instanceof RequestVote) || canGrantVote((RequestVote) rpc)) {
+ restartLastLeaderMessageTimer();
+ scheduleElection(electionDuration());
}
- if (message instanceof ElectionTimeout) {
- if(canStartElection()) {
- LOG.debug("{}: Received ElectionTimeout - switching to Candidate", logName());
+ return super.handleMessage(sender, rpc);
+ }
+
+ private RaftActorBehavior handleElectionTimeout(Object message) {
+ // If the message is ElectionTimeout, verify we haven't actually seen a message from the leader
+ // during the election timeout interval. It may that the election timer expired b/c this actor
+ // was busy and messages got delayed, in which case leader messages would be backed up in the
+ // queue but would be processed before the ElectionTimeout message and thus would restart the
+ // lastLeaderMessageTimer.
+ long lastLeaderMessageInterval = lastLeaderMessageTimer.elapsed(TimeUnit.MILLISECONDS);
+ boolean noLeaderMessageReceived = !lastLeaderMessageTimer.isRunning() || lastLeaderMessageInterval >=
+ context.getConfigParams().getElectionTimeOutInterval().toMillis();
+
+ if(canStartElection()) {
+ if(message instanceof TimeoutNow || noLeaderMessageReceived) {
+ LOG.debug("{}: Received {} - switching to Candidate", logName(), message.getClass().getSimpleName());
return internalSwitchBehavior(RaftState.Candidate);
} else {
- return this;
+ LOG.debug("{}: Received ElectionTimeout but lastLeaderMessageInterval {} < election timeout",
+ logName(), lastLeaderMessageInterval);
+ scheduleElection(electionDuration());
+ }
+ } else if(message instanceof ElectionTimeout) {
+ if(noLeaderMessageReceived) {
+ setLeaderId(null);
}
- } else if (message instanceof InstallSnapshot) {
- InstallSnapshot installSnapshot = (InstallSnapshot) message;
- handleInstallSnapshot(sender, installSnapshot);
- }
-
- if(message instanceof RaftRPC && (!(message instanceof RequestVote) || (canGrantVote((RequestVote) message)))){
scheduleElection(electionDuration());
}
- return super.handleMessage(sender, message);
+ return this;
}
private void handleInstallSnapshot(final ActorRef sender, InstallSnapshot installSnapshot) {
installSnapshot.getLastIncludedTerm(),
context.getTermInformation().getCurrentTerm(),
context.getTermInformation().getVotedFor(),
- context.getPeerServerInfo(true));
+ installSnapshot.getServerConfig().orNull());
ApplySnapshot.Callback applySnapshotCallback = new ApplySnapshot.Callback() {
@Override
Code Review / controller.git / blobdiff