import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Optional;
import com.google.common.base.Preconditions;
-import com.google.common.collect.ImmutableMap;
-import com.google.common.collect.ImmutableMap.Builder;
import com.google.protobuf.ByteString;
import java.io.IOException;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
+import java.util.Queue;
import javax.annotation.Nullable;
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.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.Snapshot;
+import org.opendaylight.controller.cluster.raft.VotingState;
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.InstallSnapshotReply;
import org.opendaylight.controller.cluster.raft.messages.RaftRPC;
import org.opendaylight.controller.cluster.raft.messages.RequestVoteReply;
+import org.opendaylight.controller.cluster.raft.messages.UnInitializedFollowerSnapshotReply;
+import org.opendaylight.controller.cluster.raft.persisted.ServerConfigurationPayload;
import scala.concurrent.duration.FiniteDuration;
/**
* set commitIndex = N (§5.3, §5.4).
*/
public abstract class AbstractLeader extends AbstractRaftActorBehavior {
+ private final Map<String, FollowerLogInformation> followerToLog = new HashMap<>();
- // The index of the first chunk that is sent when installing a snapshot
- public static final int FIRST_CHUNK_INDEX = 1;
-
- // The index that the follower should respond with if it needs the install snapshot to be reset
- public static final int INVALID_CHUNK_INDEX = -1;
-
- // This would be passed as the hash code of the last chunk when sending the first chunk
- public static final int INITIAL_LAST_CHUNK_HASH_CODE = -1;
-
- private final Map<String, FollowerLogInformation> followerToLog;
- private final Map<String, FollowerToSnapshot> mapFollowerToSnapshot = new HashMap<>();
+ /**
+ * Lookup table for request contexts based on journal index. We could use a {@link Map} here, but we really
+ * expect the entries to be modified in sequence, hence we open-code the lookup.
+ *
+ * TODO: Evaluate the use of ArrayDeque(), as that has lower memory overhead. Non-head removals are more costly,
+ * but we already expect those to be far from frequent.
+ */
+ private final Queue<ClientRequestTracker> trackers = new LinkedList<>();
private Cancellable heartbeatSchedule = null;
+ private Optional<SnapshotHolder> snapshot = Optional.absent();;
+ private int minReplicationCount;
- private final Collection<ClientRequestTracker> trackerList = new LinkedList<>();
-
- protected final int minReplicationCount;
-
- protected final int minIsolatedLeaderPeerCount;
-
- private Optional<SnapshotHolder> snapshot;
+ protected AbstractLeader(RaftActorContext context, RaftState state,
+ @Nullable AbstractLeader initializeFromLeader) {
+ super(context, state);
- public AbstractLeader(RaftActorContext context) {
- super(context, RaftState.Leader);
-
- setLeaderPayloadVersion(context.getPayloadVersion());
-
- final Builder<String, FollowerLogInformation> ftlBuilder = ImmutableMap.builder();
- for (String followerId : context.getPeerAddresses().keySet()) {
- FollowerLogInformation followerLogInformation =
- new FollowerLogInformationImpl(followerId, -1, context);
-
- ftlBuilder.put(followerId, followerLogInformation);
+ if(initializeFromLeader != null) {
+ followerToLog.putAll(initializeFromLeader.followerToLog);
+ snapshot = initializeFromLeader.snapshot;
+ trackers.addAll(initializeFromLeader.trackers);
+ } else {
+ for(PeerInfo peerInfo: context.getPeers()) {
+ FollowerLogInformation followerLogInformation = new FollowerLogInformationImpl(peerInfo, -1, context);
+ followerToLog.put(peerInfo.getId(), followerLogInformation);
+ }
}
- followerToLog = ftlBuilder.build();
-
- leaderId = context.getId();
LOG.debug("{}: Election: Leader has following peers: {}", logName(), getFollowerIds());
- minReplicationCount = getMajorityVoteCount(getFollowerIds().size());
-
- // the isolated Leader peer count will be 1 less than the majority vote count.
- // this is because the vote count has the self vote counted in it
- // for e.g
- // 0 peers = 1 votesRequired , minIsolatedLeaderPeerCount = 0
- // 2 peers = 2 votesRequired , minIsolatedLeaderPeerCount = 1
- // 4 peers = 3 votesRequired, minIsolatedLeaderPeerCount = 2
- minIsolatedLeaderPeerCount = minReplicationCount > 0 ? (minReplicationCount - 1) : 0;
-
- snapshot = Optional.absent();
+ updateMinReplicaCount();
// Immediately schedule a heartbeat
// Upon election: send initial empty AppendEntries RPCs
scheduleHeartBeat(context.getConfigParams().getHeartBeatInterval());
}
+ protected AbstractLeader(RaftActorContext context, RaftState state) {
+ this(context, state, null);
+ }
+
/**
* Return an immutable collection of follower identifiers.
*
return followerToLog.keySet();
}
+ public void addFollower(String followerId) {
+ FollowerLogInformation followerLogInformation = new FollowerLogInformationImpl(
+ context.getPeerInfo(followerId), -1, context);
+ followerToLog.put(followerId, followerLogInformation);
+
+ if(heartbeatSchedule == null) {
+ scheduleHeartBeat(context.getConfigParams().getHeartBeatInterval());
+ }
+ }
+
+ public void removeFollower(String followerId) {
+ followerToLog.remove(followerId);
+ }
+
+ public void updateMinReplicaCount() {
+ int numVoting = 0;
+ for(PeerInfo peer: context.getPeers()) {
+ if(peer.isVoting()) {
+ numVoting++;
+ }
+ }
+
+ minReplicationCount = getMajorityVoteCount(numVoting);
+ }
+
+ protected int getMinIsolatedLeaderPeerCount(){
+ //the isolated Leader peer count will be 1 less than the majority vote count.
+ //this is because the vote count has the self vote counted in it
+ //for e.g
+ //0 peers = 1 votesRequired , minIsolatedLeaderPeerCount = 0
+ //2 peers = 2 votesRequired , minIsolatedLeaderPeerCount = 1
+ //4 peers = 3 votesRequired, minIsolatedLeaderPeerCount = 2
+
+ return minReplicationCount > 0 ? (minReplicationCount - 1) : 0;
+ }
+
@VisibleForTesting
void setSnapshot(@Nullable Snapshot snapshot) {
if(snapshot != null) {
}
}
+ @VisibleForTesting
+ boolean hasSnapshot() {
+ return snapshot.isPresent();
+ }
+
@Override
protected RaftActorBehavior handleAppendEntries(ActorRef sender,
AppendEntries appendEntries) {
followerLogInformation.markFollowerActive();
followerLogInformation.setPayloadVersion(appendEntriesReply.getPayloadVersion());
+ followerLogInformation.setRaftVersion(appendEntriesReply.getRaftVersion());
boolean updated = false;
- if (appendEntriesReply.isSuccess()) {
+ if(appendEntriesReply.getLogLastIndex() > context.getReplicatedLog().lastIndex()) {
+ // The follower's log is actually ahead of the leader's log. Normally this doesn't happen
+ // in raft as a node cannot become leader if it's log is behind another's. However, the
+ // non-voting semantics deviate a bit from raft. Only voting members participate in
+ // elections and can become leader so it's possible for a non-voting follower to be ahead
+ // of the leader. This can happen if persistence is disabled and all voting members are
+ // restarted. In this case, the voting leader will start out with an empty log however
+ // the non-voting followers still retain the previous data in memory. On the first
+ // AppendEntries, the non-voting follower returns a successful reply b/c the prevLogIndex
+ // sent by the leader is -1 and thus the integrity checks pass. However the follower's returned
+ // lastLogIndex may be higher in which case we want to reset the follower by installing a
+ // snapshot. It's also possible that the follower's last log index is behind the leader's.
+ // However in this case the log terms won't match and the logs will conflict - this is handled
+ // elsewhere.
+ LOG.debug("{}: handleAppendEntriesReply: follower {} lastIndex {} is ahead of our lastIndex {} - forcing install snaphot",
+ logName(), followerLogInformation.getId(), appendEntriesReply.getLogLastIndex(),
+ context.getReplicatedLog().lastIndex());
+
+ followerLogInformation.setMatchIndex(-1);
+ followerLogInformation.setNextIndex(-1);
+
+ initiateCaptureSnapshot(followerId);
+ updated = true;
+ } else if (appendEntriesReply.isSuccess()) {
updated = updateFollowerLogInformation(followerLogInformation, appendEntriesReply);
} else {
LOG.debug("{}: handleAppendEntriesReply: received unsuccessful reply: {}", logName(), appendEntriesReply);
long followerLastLogIndex = appendEntriesReply.getLogLastIndex();
- ReplicatedLogEntry followersLastLogEntry = context.getReplicatedLog().get(followerLastLogIndex);
- if(followerLastLogIndex < 0 || (followersLastLogEntry != null &&
- followersLastLogEntry.getTerm() == appendEntriesReply.getLogLastTerm())) {
+ long followersLastLogTerm = getLogEntryTerm(followerLastLogIndex);
+ if(appendEntriesReply.isForceInstallSnapshot()) {
+ // Reset the followers match and next index. This is to signal that this follower has nothing
+ // in common with this Leader and so would require a snapshot to be installed
+ followerLogInformation.setMatchIndex(-1);
+ followerLogInformation.setNextIndex(-1);
+
+ // Force initiate a snapshot capture
+ initiateCaptureSnapshot(followerId);
+ } else if(followerLastLogIndex < 0 || (followersLastLogTerm >= 0 &&
+ followersLastLogTerm == appendEntriesReply.getLogLastTerm())) {
// The follower's log is empty or the last entry is present in the leader's journal
// and the terms match so the follower is just behind the leader's journal from
// the last snapshot, if any. We'll catch up the follower quickly by starting at the
updated = updateFollowerLogInformation(followerLogInformation, appendEntriesReply);
} 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.
+ // The follower's log conflicts with leader's log so decrement follower's next index by 1
+ // in an attempt to find where the logs match.
+
+ LOG.debug("{}: follower's last log term {} conflicts with the leader's {} - dec next index",
+ logName(), appendEntriesReply.getLogLastTerm(), followersLastLogTerm);
followerLogInformation.decrNextIndex();
}
// 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).
+ if(LOG.isTraceEnabled()) {
+ LOG.trace("{}: handleAppendEntriesReply from {}: commitIndex: {}, lastAppliedIndex: {}, currentTerm: {}",
+ logName(), followerId, context.getCommitIndex(), context.getLastApplied(), currentTerm());
+ }
+
for (long N = context.getCommitIndex() + 1; ; N++) {
int replicatedCount = 1;
+ LOG.trace("{}: checking Nth index {}", logName(), N);
for (FollowerLogInformation info : followerToLog.values()) {
- if (info.getMatchIndex() >= N) {
+ final PeerInfo peerInfo = context.getPeerInfo(info.getId());
+ if(info.getMatchIndex() >= N && peerInfo != null && peerInfo.isVoting()) {
replicatedCount++;
+ } else if(LOG.isTraceEnabled()) {
+ LOG.trace("{}: Not counting follower {} - matchIndex: {}, {}", logName(), info.getId(),
+ info.getMatchIndex(), peerInfo);
}
}
+ if(LOG.isTraceEnabled()) {
+ LOG.trace("{}: replicatedCount {}, minReplicationCount: {}", logName(), replicatedCount, minReplicationCount);
+ }
+
if (replicatedCount >= minReplicationCount) {
ReplicatedLogEntry replicatedLogEntry = context.getReplicatedLog().get(N);
- if (replicatedLogEntry != null &&
- replicatedLogEntry.getTerm() == currentTerm()) {
+ if (replicatedLogEntry == null) {
+ LOG.debug("{}: ReplicatedLogEntry not found for index {} - snapshotIndex: {}, journal size: {}",
+ logName(), N, context.getReplicatedLog().getSnapshotIndex(), context.getReplicatedLog().size());
+ break;
+ }
+
+ // Don't update the commit index if the log entry is from a previous term, as per §5.4.1:
+ // "Raft never commits log entries from previous terms by counting replicas".
+ // However we keep looping so we can make progress when new entries in the current term
+ // reach consensus, as per §5.4.1: "once an entry from the current term is committed by
+ // counting replicas, then all prior entries are committed indirectly".
+ if (replicatedLogEntry.getTerm() == currentTerm()) {
+ LOG.trace("{}: Setting commit index to {}", logName(), N);
context.setCommitIndex(N);
+ } else {
+ LOG.debug("{}: Not updating commit index to {} - retrieved log entry with index {}, term {} does not match the current term {}",
+ logName(), N, replicatedLogEntry.getIndex(), replicatedLogEntry.getTerm(), currentTerm());
}
} else {
+ LOG.trace("{}: minReplicationCount not reached, actual {} - breaking", logName(), replicatedCount);
break;
}
}
//Send the next log entry immediately, if possible, no need to wait for heartbeat to trigger that event
sendUpdatesToFollower(followerId, followerLogInformation, false, !updated);
+
return this;
}
@Override
protected ClientRequestTracker removeClientRequestTracker(long logIndex) {
- final Iterator<ClientRequestTracker> it = trackerList.iterator();
+ final Iterator<ClientRequestTracker> it = trackers.iterator();
while (it.hasNext()) {
final ClientRequestTracker t = it.next();
if (t.getIndex() == logIndex) {
return null;
}
- @Override
- protected ClientRequestTracker findClientRequestTracker(long logIndex) {
- for (ClientRequestTracker tracker : trackerList) {
- if (tracker.getIndex() == logIndex) {
- return tracker;
- }
- }
- return null;
- }
-
@Override
protected RaftActorBehavior handleRequestVoteReply(ActorRef sender,
RequestVoteReply requestVoteReply) {
protected void beforeSendHeartbeat(){}
@Override
- public RaftActorBehavior handleMessage(ActorRef sender, Object originalMessage) {
+ public RaftActorBehavior handleMessage(ActorRef sender, Object message) {
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:
beforeSendHeartbeat();
sendHeartBeat();
scheduleHeartBeat(context.getConfigParams().getHeartBeatInterval());
- return this;
-
} else if(message instanceof SendInstallSnapshot) {
// received from RaftActor
setSnapshot(((SendInstallSnapshot) message).getSnapshot());
sendInstallSnapshot();
-
} else if (message instanceof Replicate) {
replicate((Replicate) message);
-
- } else if (message instanceof InstallSnapshotReply){
+ } else if (message instanceof InstallSnapshotReply) {
handleInstallSnapshotReply((InstallSnapshotReply) message);
-
+ } else {
+ return super.handleMessage(sender, message);
}
-
- return super.handleMessage(sender, message);
+ return this;
}
private void handleInstallSnapshotReply(InstallSnapshotReply reply) {
LOG.debug("{}: handleInstallSnapshotReply: {}", logName(), reply);
String followerId = reply.getFollowerId();
- FollowerToSnapshot followerToSnapshot = mapFollowerToSnapshot.get(followerId);
+ FollowerLogInformation followerLogInformation = followerToLog.get(followerId);
+ if(followerLogInformation == null) {
+ // This can happen during AddServer if it times out.
+ LOG.error("{}: FollowerLogInformation not found for follower {} in InstallSnapshotReply",
+ logName(), followerId);
+ return;
+ }
- if (followerToSnapshot == null) {
- LOG.error("{}: FollowerId {} in InstallSnapshotReply not known to Leader",
+ LeaderInstallSnapshotState installSnapshotState = followerLogInformation.getInstallSnapshotState();
+ if (installSnapshotState == null) {
+ LOG.error("{}: LeaderInstallSnapshotState not found for follower {} in InstallSnapshotReply",
logName(), followerId);
return;
}
- FollowerLogInformation followerLogInformation = followerToLog.get(followerId);
followerLogInformation.markFollowerActive();
- if (followerToSnapshot.getChunkIndex() == reply.getChunkIndex()) {
+ if (installSnapshotState.getChunkIndex() == reply.getChunkIndex()) {
boolean wasLastChunk = false;
if (reply.isSuccess()) {
- if(followerToSnapshot.isLastChunk(reply.getChunkIndex())) {
+ if(installSnapshotState.isLastChunk(reply.getChunkIndex())) {
//this was the last chunk reply
if(LOG.isDebugEnabled()) {
LOG.debug("{}: InstallSnapshotReply received, " +
long followerMatchIndex = snapshot.get().getLastIncludedIndex();
followerLogInformation.setMatchIndex(followerMatchIndex);
followerLogInformation.setNextIndex(followerMatchIndex + 1);
- mapFollowerToSnapshot.remove(followerId);
+ followerLogInformation.clearLeaderInstallSnapshotState();
LOG.debug("{}: follower: {}, matchIndex set to {}, nextIndex set to {}",
- logName(), followerId, followerLogInformation.getMatchIndex(),
- followerLogInformation.getNextIndex());
+ logName(), followerId, followerLogInformation.getMatchIndex(),
+ followerLogInformation.getNextIndex());
- if (mapFollowerToSnapshot.isEmpty()) {
+ if (!anyFollowersInstallingSnapshot()) {
// once there are no pending followers receiving snapshots
// we can remove snapshot from the memory
setSnapshot(null);
}
- wasLastChunk = true;
+ wasLastChunk = true;
+ if(context.getPeerInfo(followerId).getVotingState() == VotingState.VOTING_NOT_INITIALIZED){
+ UnInitializedFollowerSnapshotReply unInitFollowerSnapshotSuccess =
+ new UnInitializedFollowerSnapshotReply(followerId);
+ context.getActor().tell(unInitFollowerSnapshotSuccess, context.getActor());
+ LOG.debug("Sent message UnInitializedFollowerSnapshotReply to self");
+ }
} else {
- followerToSnapshot.markSendStatus(true);
+ installSnapshotState.markSendStatus(true);
}
} else {
LOG.info("{}: InstallSnapshotReply received sending snapshot chunk failed, Will retry, Chunk: {}",
logName(), reply.getChunkIndex());
- followerToSnapshot.markSendStatus(false);
+ installSnapshotState.markSendStatus(false);
}
if (wasLastChunk && !context.getSnapshotManager().isCapturing()) {
// Since the follower is now caught up try to purge the log.
purgeInMemoryLog();
- } else if (!wasLastChunk && followerToSnapshot.canSendNextChunk()) {
+ } else if (!wasLastChunk && installSnapshotState.canSendNextChunk()) {
ActorSelection followerActor = context.getPeerActorSelection(followerId);
if(followerActor != null) {
sendSnapshotChunk(followerActor, followerId);
} else {
LOG.error("{}: Chunk index {} in InstallSnapshotReply from follower {} does not match expected index {}",
logName(), reply.getChunkIndex(), followerId,
- followerToSnapshot.getChunkIndex());
+ installSnapshotState.getChunkIndex());
- if(reply.getChunkIndex() == INVALID_CHUNK_INDEX){
+ if(reply.getChunkIndex() == LeaderInstallSnapshotState.INVALID_CHUNK_INDEX){
// Since the Follower did not find this index to be valid we should reset the follower snapshot
// so that Installing the snapshot can resume from the beginning
- followerToSnapshot.reset();
+ installSnapshotState.reset();
}
}
}
+ private boolean anyFollowersInstallingSnapshot() {
+ for(FollowerLogInformation info: followerToLog.values()) {
+ if(info.getInstallSnapshotState() != null) {
+ return true;
+ }
+
+ }
+
+ return false;
+ }
+
private void replicate(Replicate replicate) {
long logIndex = replicate.getReplicatedLogEntry().getIndex();
- LOG.debug("{}: Replicate message: identifier: {}, logIndex: {}", logName(),
- replicate.getIdentifier(), logIndex);
+ LOG.debug("{}: Replicate message: identifier: {}, logIndex: {}, payload: {}", logName(),
+ replicate.getIdentifier(), logIndex, replicate.getReplicatedLogEntry().getData().getClass());
// Create a tracker entry we will use this later to notify the
// client actor
- trackerList.add(
- new ClientRequestTrackerImpl(replicate.getClientActor(),
- replicate.getIdentifier(),
- logIndex)
- );
+ if(replicate.getClientActor() != null) {
+ trackers.add(new ClientRequestTrackerImpl(replicate.getClientActor(), replicate.getIdentifier(),
+ logIndex));
+ }
- boolean applyModificationToState = followerToLog.isEmpty()
+ boolean applyModificationToState = !context.anyVotingPeers()
|| context.getRaftPolicy().applyModificationToStateBeforeConsensus();
if(applyModificationToState){
}
}
- private void sendAppendEntries(long timeSinceLastActivityInterval, boolean isHeartbeat) {
+ protected void sendAppendEntries(long timeSinceLastActivityInterval, boolean isHeartbeat) {
// Send an AppendEntries to all followers
for (Entry<String, FollowerLogInformation> e : followerToLog.entrySet()) {
final String followerId = e.getKey();
boolean sendAppendEntries = false;
List<ReplicatedLogEntry> entries = Collections.emptyList();
- if (mapFollowerToSnapshot.get(followerId) != null) {
+ LeaderInstallSnapshotState installSnapshotState = followerLogInformation.getInstallSnapshotState();
+ if (installSnapshotState != null) {
// if install snapshot is in process , then sent next chunk if possible
- if (isFollowerActive && mapFollowerToSnapshot.get(followerId).canSendNextChunk()) {
+ if (isFollowerActive && installSnapshotState.canSendNextChunk()) {
sendSnapshotChunk(followerActor, followerId);
} else if(sendHeartbeat) {
// we send a heartbeat even if we have not received a reply for the last chunk
// then snapshot should be sent
if (LOG.isDebugEnabled()) {
- LOG.debug(String.format("%s: InitiateInstallSnapshot to follower: %s," +
+ LOG.debug(String.format("%s: InitiateInstallSnapshot to follower: %s, " +
"follower-nextIndex: %d, leader-snapshot-index: %d, " +
"leader-last-index: %d", logName(), followerId,
followerNextIndex, leaderSnapShotIndex, leaderLastIndex));
// Send heartbeat to follower whenever install snapshot is initiated.
sendAppendEntries = true;
- initiateCaptureSnapshot(followerId, followerNextIndex);
+ if (canInstallSnapshot(followerNextIndex)) {
+ initiateCaptureSnapshot(followerId);
+ }
} else if(sendHeartbeat) {
// we send an AppendEntries, even if the follower is inactive
private void sendAppendEntriesToFollower(ActorSelection followerActor, long followerNextIndex,
List<ReplicatedLogEntry> entries, String followerId) {
AppendEntries appendEntries = new AppendEntries(currentTerm(), context.getId(),
- prevLogIndex(followerNextIndex),
- prevLogTerm(followerNextIndex), entries,
+ getLogEntryIndex(followerNextIndex - 1),
+ getLogEntryTerm(followerNextIndex - 1), entries,
context.getCommitIndex(), super.getReplicatedToAllIndex(), context.getPayloadVersion());
if(!entries.isEmpty() || LOG.isTraceEnabled()) {
appendEntries);
}
- followerActor.tell(appendEntries.toSerializable(), actor());
+ followerActor.tell(appendEntries, actor());
}
/**
* 6. If another follower requires a snapshot and a snapshot has been collected (via CaptureSnapshotReply)
* then send the existing snapshot in chunks to the follower.
* @param followerId
- * @param followerNextIndex
*/
- private void initiateCaptureSnapshot(String followerId, long followerNextIndex) {
- if (!context.getReplicatedLog().isPresent(followerNextIndex) &&
- context.getReplicatedLog().isInSnapshot(followerNextIndex)) {
-
- if (snapshot.isPresent()) {
- // if a snapshot is present in the memory, most likely another install is in progress
- // no need to capture snapshot.
- // This could happen if another follower needs an install when one is going on.
- final ActorSelection followerActor = context.getPeerActorSelection(followerId);
- sendSnapshotChunk(followerActor, followerId);
+ public boolean initiateCaptureSnapshot(String followerId) {
+ if (snapshot.isPresent()) {
+ // if a snapshot is present in the memory, most likely another install is in progress
+ // no need to capture snapshot.
+ // This could happen if another follower needs an install when one is going on.
+ final ActorSelection followerActor = context.getPeerActorSelection(followerId);
+ sendSnapshotChunk(followerActor, followerId);
+ return true;
+ } else {
+ return context.getSnapshotManager().captureToInstall(context.getReplicatedLog().last(),
+ this.getReplicatedToAllIndex(), followerId);
+ }
+ }
+ private boolean canInstallSnapshot(long nextIndex){
+ // If the follower's nextIndex is -1 then we might as well send it a snapshot
+ // Otherwise send it a snapshot only if the nextIndex is not present in the log but is present
+ // in the snapshot
+ return nextIndex == -1 ||
+ (!context.getReplicatedLog().isPresent(nextIndex)
+ && context.getReplicatedLog().isInSnapshot(nextIndex));
- } else {
- context.getSnapshotManager().captureToInstall(context.getReplicatedLog().last(),
- this.getReplicatedToAllIndex(), followerId);
- }
- }
}
private void sendInstallSnapshot() {
LOG.debug("{}: sendInstallSnapshot", logName());
for (Entry<String, FollowerLogInformation> e : followerToLog.entrySet()) {
- ActorSelection followerActor = context.getPeerActorSelection(e.getKey());
+ String followerId = e.getKey();
+ ActorSelection followerActor = context.getPeerActorSelection(followerId);
+ FollowerLogInformation followerLogInfo = e.getValue();
if (followerActor != null) {
- long nextIndex = e.getValue().getNextIndex();
-
- if (!context.getReplicatedLog().isPresent(nextIndex) &&
- context.getReplicatedLog().isInSnapshot(nextIndex)) {
- sendSnapshotChunk(followerActor, e.getKey());
+ long nextIndex = followerLogInfo.getNextIndex();
+ if (context.getPeerInfo(followerId).getVotingState() == VotingState.VOTING_NOT_INITIALIZED ||
+ canInstallSnapshot(nextIndex)) {
+ sendSnapshotChunk(followerActor, followerId);
}
}
}
private void sendSnapshotChunk(ActorSelection followerActor, String followerId) {
try {
if (snapshot.isPresent()) {
- ByteString nextSnapshotChunk = getNextSnapshotChunk(followerId, snapshot.get().getSnapshotBytes());
+ byte[] nextSnapshotChunk = getNextSnapshotChunk(followerId, snapshot.get().getSnapshotBytes());
// Note: the previous call to getNextSnapshotChunk has the side-effect of adding
// followerId to the followerToSnapshot map.
- FollowerToSnapshot followerToSnapshot = mapFollowerToSnapshot.get(followerId);
+ LeaderInstallSnapshotState installSnapshotState = followerToLog.get(followerId).getInstallSnapshotState();
+
+ int nextChunkIndex = installSnapshotState.incrementChunkIndex();
+ Optional<ServerConfigurationPayload> serverConfig = Optional.absent();
+ if(installSnapshotState.isLastChunk(nextChunkIndex)) {
+ serverConfig = Optional.fromNullable(context.getPeerServerInfo(true));
+ }
followerActor.tell(
new InstallSnapshot(currentTerm(), context.getId(),
snapshot.get().getLastIncludedIndex(),
snapshot.get().getLastIncludedTerm(),
nextSnapshotChunk,
- followerToSnapshot.incrementChunkIndex(),
- followerToSnapshot.getTotalChunks(),
- Optional.of(followerToSnapshot.getLastChunkHashCode())
- ).toSerializable(),
+ nextChunkIndex,
+ installSnapshotState.getTotalChunks(),
+ Optional.of(installSnapshotState.getLastChunkHashCode()),
+ serverConfig
+ ).toSerializable(followerToLog.get(followerId).getRaftVersion()),
actor()
);
if(LOG.isDebugEnabled()) {
LOG.debug("{}: InstallSnapshot sent to follower {}, Chunk: {}/{}",
- logName(), followerActor.path(), followerToSnapshot.getChunkIndex(),
- followerToSnapshot.getTotalChunks());
+ logName(), followerActor.path(), installSnapshotState.getChunkIndex(),
+ installSnapshotState.getTotalChunks());
}
}
} catch (IOException e) {
* Acccepts snaphot as ByteString, enters into map for future chunks
* creates and return a ByteString chunk
*/
- private ByteString getNextSnapshotChunk(String followerId, ByteString snapshotBytes) throws IOException {
- FollowerToSnapshot followerToSnapshot = mapFollowerToSnapshot.get(followerId);
- if (followerToSnapshot == null) {
- followerToSnapshot = new FollowerToSnapshot(snapshotBytes);
- mapFollowerToSnapshot.put(followerId, followerToSnapshot);
+ private byte[] getNextSnapshotChunk(String followerId, ByteString snapshotBytes) throws IOException {
+ LeaderInstallSnapshotState installSnapshotState = followerToLog.get(followerId).getInstallSnapshotState();
+ if (installSnapshotState == null) {
+ installSnapshotState = new LeaderInstallSnapshotState(snapshotBytes, context.getConfigParams().getSnapshotChunkSize(),
+ logName());
+ followerToLog.get(followerId).setLeaderInstallSnapshotState(installSnapshotState);
}
- ByteString nextChunk = followerToSnapshot.getNextChunk();
+ byte[] nextChunk = installSnapshotState.getNextChunk();
- LOG.debug("{}: next snapshot chunk size for follower {}: {}", logName(), followerId, nextChunk.size());
+ LOG.debug("{}: next snapshot chunk size for follower {}: {}", logName(), followerId, nextChunk.length);
return nextChunk;
}
// 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(),
+ interval, context.getActor(), SendHeartBeat.INSTANCE,
context.getActorSystem().dispatcher(), context.getActor());
}
@Override
- public void close() throws Exception {
+ public void close() {
stopHeartBeat();
}
@Override
- public String getLeaderId() {
+ public final String getLeaderId() {
return context.getId();
}
+ @Override
+ public final short getLeaderPayloadVersion() {
+ return context.getPayloadVersion();
+ }
+
protected boolean isLeaderIsolated() {
- int minPresent = minIsolatedLeaderPeerCount;
+ int minPresent = getMinIsolatedLeaderPeerCount();
for (FollowerLogInformation followerLogInformation : followerToLog.values()) {
- if (followerLogInformation.isFollowerActive()) {
+ final PeerInfo peerInfo = context.getPeerInfo(followerLogInformation.getId());
+ if(peerInfo != null && peerInfo.isVoting() && followerLogInformation.isFollowerActive()) {
--minPresent;
if (minPresent == 0) {
- break;
+ return false;
}
}
}
- return (minPresent != 0);
- }
-
- /**
- * Encapsulates the snapshot bytestring and handles the logic of sending
- * snapshot chunks
- */
- protected class FollowerToSnapshot {
- private final ByteString snapshotBytes;
- private int offset = 0;
- // the next snapshot chunk is sent only if the replyReceivedForOffset matches offset
- private int replyReceivedForOffset;
- // if replyStatus is false, the previous chunk is attempted
- private boolean replyStatus = false;
- private int chunkIndex;
- private final int totalChunks;
- private int lastChunkHashCode = AbstractLeader.INITIAL_LAST_CHUNK_HASH_CODE;
- private int nextChunkHashCode = AbstractLeader.INITIAL_LAST_CHUNK_HASH_CODE;
-
- public FollowerToSnapshot(ByteString snapshotBytes) {
- this.snapshotBytes = snapshotBytes;
- int size = snapshotBytes.size();
- totalChunks = ( size / context.getConfigParams().getSnapshotChunkSize()) +
- ((size % context.getConfigParams().getSnapshotChunkSize()) > 0 ? 1 : 0);
- if(LOG.isDebugEnabled()) {
- LOG.debug("{}: Snapshot {} bytes, total chunks to send:{}",
- logName(), size, totalChunks);
- }
- replyReceivedForOffset = -1;
- chunkIndex = AbstractLeader.FIRST_CHUNK_INDEX;
- }
-
- public ByteString getSnapshotBytes() {
- return snapshotBytes;
- }
-
- public int incrementOffset() {
- if(replyStatus) {
- // if prev chunk failed, we would want to sent the same chunk again
- offset = offset + context.getConfigParams().getSnapshotChunkSize();
- }
- return offset;
- }
-
- public int incrementChunkIndex() {
- if (replyStatus) {
- // if prev chunk failed, we would want to sent the same chunk again
- chunkIndex = chunkIndex + 1;
- }
- return chunkIndex;
- }
-
- public int getChunkIndex() {
- return chunkIndex;
- }
-
- public int getTotalChunks() {
- return totalChunks;
- }
-
- public boolean canSendNextChunk() {
- // we only send a false if a chunk is sent but we have not received a reply yet
- return replyReceivedForOffset == offset;
- }
-
- public boolean isLastChunk(int chunkIndex) {
- return totalChunks == chunkIndex;
- }
-
- public void markSendStatus(boolean success) {
- if (success) {
- // if the chunk sent was successful
- replyReceivedForOffset = offset;
- replyStatus = true;
- lastChunkHashCode = nextChunkHashCode;
- } else {
- // if the chunk sent was failure
- replyReceivedForOffset = offset;
- replyStatus = false;
- }
- }
-
- public ByteString getNextChunk() {
- int snapshotLength = getSnapshotBytes().size();
- int start = incrementOffset();
- int size = context.getConfigParams().getSnapshotChunkSize();
- if (context.getConfigParams().getSnapshotChunkSize() > snapshotLength) {
- size = snapshotLength;
- } else {
- if ((start + context.getConfigParams().getSnapshotChunkSize()) > snapshotLength) {
- size = snapshotLength - start;
- }
- }
-
-
- LOG.debug("{}: Next chunk: length={}, offset={},size={}", logName(),
- snapshotLength, start, size);
-
- ByteString substring = getSnapshotBytes().substring(start, start + size);
- nextChunkHashCode = substring.hashCode();
- return substring;
- }
-
- /**
- * reset should be called when the Follower needs to be sent the snapshot from the beginning
- */
- public void reset(){
- offset = 0;
- replyStatus = false;
- replyReceivedForOffset = offset;
- chunkIndex = AbstractLeader.FIRST_CHUNK_INDEX;
- lastChunkHashCode = AbstractLeader.INITIAL_LAST_CHUNK_HASH_CODE;
- }
-
- public int getLastChunkHashCode() {
- return lastChunkHashCode;
- }
+ return minPresent != 0;
}
// called from example-actor for printing the follower-states
return followerToLog.get(followerId);
}
- @VisibleForTesting
- protected void setFollowerSnapshot(String followerId, FollowerToSnapshot snapshot) {
- mapFollowerToSnapshot.put(followerId, snapshot);
- }
-
- @VisibleForTesting
- public int followerSnapshotSize() {
- return mapFollowerToSnapshot.size();
- }
-
@VisibleForTesting
public int followerLogSize() {
return followerToLog.size();
Code Review / controller.git / blobdiff