import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
-import java.util.concurrent.TimeUnit;
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.RaftState;
import org.opendaylight.controller.cluster.raft.ReplicatedLogEntry;
import org.opendaylight.controller.cluster.raft.base.messages.CaptureSnapshot;
-import org.opendaylight.controller.cluster.raft.base.messages.InitiateInstallSnapshot;
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;
// 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));
+ sendAppendEntries(0);
}
/**
applyLogToStateMachine(context.getCommitIndex());
}
+ if (!context.isSnapshotCaptureInitiated()) {
+ purgeInMemoryLog();
+ }
+
+ //Send the next log entry immediately, if possible, no need to wait for heartbeat to trigger that event
+ sendUpdatesToFollower(followerId, followerLogInformation, false);
return this;
}
+ private void purgeInMemoryLog() {
+ //find the lowest index across followers which has been replicated to all.
+ // lastApplied if there are no followers, so that we keep clearing the log for single-node
+ // we would delete the in-mem log from that index on, in-order to minimize mem usage
+ // we would also share this info thru AE with the followers so that they can delete their log entries as well.
+ long minReplicatedToAllIndex = followerToLog.isEmpty() ? context.getLastApplied() : Long.MAX_VALUE;
+ for (FollowerLogInformation info : followerToLog.values()) {
+ minReplicatedToAllIndex = Math.min(minReplicatedToAllIndex, info.getMatchIndex());
+ }
+
+ super.performSnapshotWithoutCapture(minReplicatedToAllIndex);
+ }
+
@Override
protected ClientRequestTracker removeClientRequestTracker(long logIndex) {
final Iterator<ClientRequestTracker> it = trackerList.iterator();
// 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 leader's term {}", context.getId(),
+ rpc.getTerm(), rpc, context.getTermInformation().getCurrentTerm());
+
context.getTermInformation().updateAndPersist(rpc.getTerm(), null);
return switchBehavior(new Follower(context));
sendHeartBeat();
return this;
- } else if(message instanceof InitiateInstallSnapshot) {
- installSnapshotIfNeeded();
-
} else if(message instanceof SendInstallSnapshot) {
// received from RaftActor
setSnapshot(Optional.of(((SendInstallSnapshot) message).getSnapshot()));
private void handleInstallSnapshotReply(InstallSnapshotReply reply) {
String followerId = reply.getFollowerId();
FollowerToSnapshot followerToSnapshot = mapFollowerToSnapshot.get(followerId);
+
+ if (followerToSnapshot == null) {
+ LOG.error("{}: FollowerId {} in InstallSnapshotReply not known to Leader",
+ context.getId(), followerId);
+ return;
+ }
+
FollowerLogInformation followerLogInformation = followerToLog.get(followerId);
followerLogInformation.markFollowerActive();
- if (followerToSnapshot != null &&
- followerToSnapshot.getChunkIndex() == reply.getChunkIndex()) {
-
+ if (followerToSnapshot.getChunkIndex() == reply.getChunkIndex()) {
+ boolean wasLastChunk = false;
if (reply.isSuccess()) {
if(followerToSnapshot.isLastChunk(reply.getChunkIndex())) {
//this was the last chunk reply
// we can remove snapshot from the memory
setSnapshot(Optional.<ByteString>absent());
}
+ wasLastChunk = true;
} else {
followerToSnapshot.markSendStatus(true);
followerToSnapshot.markSendStatus(false);
}
+ if (!wasLastChunk && followerToSnapshot.canSendNextChunk()) {
+ ActorSelection followerActor = context.getPeerActorSelection(followerId);
+ if(followerActor != null) {
+ sendSnapshotChunk(followerActor, followerId);
+ }
+ }
+
} else {
- LOG.error("{}: FollowerId in InstallSnapshotReply not known to Leader" +
- " or Chunk Index in InstallSnapshotReply not matching {} != {}",
- context.getId(), followerToSnapshot.getChunkIndex(), reply.getChunkIndex()
- );
+ LOG.error("{}: Chunk index {} in InstallSnapshotReply from follower {} does not match expected index {}",
+ context.getId(), reply.getChunkIndex(), followerId,
+ followerToSnapshot.getChunkIndex());
if(reply.getChunkIndex() == INVALID_CHUNK_INDEX){
// Since the Follower did not find this index to be valid we should reset the follower snapshot
context.setCommitIndex(logIndex);
applyLogToStateMachine(logIndex);
} else {
- sendAppendEntries();
+ sendAppendEntries(0);
}
}
- private void sendAppendEntries() {
+ private void sendAppendEntries(long timeSinceLastActivityInterval) {
// Send an AppendEntries to all followers
for (Entry<String, FollowerLogInformation> e : followerToLog.entrySet()) {
final String followerId = e.getKey();
- ActorSelection followerActor = context.getPeerActorSelection(followerId);
+ final FollowerLogInformation followerLogInformation = e.getValue();
+ // This checks helps not to send a repeat message to the follower
+ if(!followerLogInformation.isFollowerActive() ||
+ followerLogInformation.timeSinceLastActivity() >= timeSinceLastActivityInterval) {
+ sendUpdatesToFollower(followerId, followerLogInformation, true);
+ }
+ }
+ }
- if (followerActor != null) {
- FollowerLogInformation followerLogInformation = followerToLog.get(followerId);
- long followerNextIndex = followerLogInformation.getNextIndex();
- boolean isFollowerActive = followerLogInformation.isFollowerActive();
-
- if (mapFollowerToSnapshot.get(followerId) != null) {
- // if install snapshot is in process , then sent next chunk if possible
- if (isFollowerActive && mapFollowerToSnapshot.get(followerId).canSendNextChunk()) {
- sendSnapshotChunk(followerActor, followerId);
- } else {
- // we send a heartbeat even if we have not received a reply for the last chunk
- sendAppendEntriesToFollower(followerActor, followerNextIndex,
- Collections.<ReplicatedLogEntry>emptyList());
- }
+ /**
+ *
+ * This method checks if any update needs to be sent to the given follower. This includes append log entries,
+ * sending next snapshot chunk, and initiating a snapshot.
+ * @return true if any update is sent, false otherwise
+ */
- } else {
- long leaderLastIndex = context.getReplicatedLog().lastIndex();
- long leaderSnapShotIndex = context.getReplicatedLog().getSnapshotIndex();
- final List<ReplicatedLogEntry> entries;
-
- if (isFollowerActive &&
- context.getReplicatedLog().isPresent(followerNextIndex)) {
- // FIXME : Sending one entry at a time
- entries = context.getReplicatedLog().getFrom(followerNextIndex, 1);
-
- } else if (isFollowerActive && followerNextIndex >= 0 &&
- leaderLastIndex >= followerNextIndex ) {
- // if the followers next index is not present in the leaders log, and
- // if the follower is just not starting and if leader's index is more than followers index
- // then snapshot should be sent
-
- if(LOG.isDebugEnabled()) {
- LOG.debug(String.format("%s: InitiateInstallSnapshot to follower: %s," +
- "follower-nextIndex: %s, leader-snapshot-index: %s, " +
- "leader-last-index: %s", context.getId(), followerId,
- followerNextIndex, leaderSnapShotIndex, leaderLastIndex));
- }
- actor().tell(new InitiateInstallSnapshot(), actor());
-
- // we would want to sent AE as the capture snapshot might take time
- entries = Collections.<ReplicatedLogEntry>emptyList();
-
- } else {
- //we send an AppendEntries, even if the follower is inactive
- // in-order to update the followers timestamp, in case it becomes active again
- entries = Collections.<ReplicatedLogEntry>emptyList();
+ private void sendUpdatesToFollower(String followerId, FollowerLogInformation followerLogInformation,
+ boolean sendHeartbeat) {
+
+ ActorSelection followerActor = context.getPeerActorSelection(followerId);
+ if (followerActor != null) {
+ long followerNextIndex = followerLogInformation.getNextIndex();
+ boolean isFollowerActive = followerLogInformation.isFollowerActive();
+
+ if (mapFollowerToSnapshot.get(followerId) != null) {
+ // if install snapshot is in process , then sent next chunk if possible
+ if (isFollowerActive && mapFollowerToSnapshot.get(followerId).canSendNextChunk()) {
+ sendSnapshotChunk(followerActor, followerId);
+ } else if(sendHeartbeat) {
+ // we send a heartbeat even if we have not received a reply for the last chunk
+ sendAppendEntriesToFollower(followerActor, followerLogInformation.getNextIndex(),
+ Collections.<ReplicatedLogEntry>emptyList(), followerId);
+ }
+ } else {
+ long leaderLastIndex = context.getReplicatedLog().lastIndex();
+ long leaderSnapShotIndex = context.getReplicatedLog().getSnapshotIndex();
+ if (isFollowerActive &&
+ context.getReplicatedLog().isPresent(followerNextIndex)) {
+ // FIXME : Sending one entry at a time
+ final List<ReplicatedLogEntry> entries = context.getReplicatedLog().getFrom(followerNextIndex, 1);
+
+ sendAppendEntriesToFollower(followerActor, followerNextIndex, entries, followerId);
+
+ } else if (isFollowerActive && followerNextIndex >= 0 &&
+ leaderLastIndex > followerNextIndex && !context.isSnapshotCaptureInitiated()) {
+ // if the followers next index is not present in the leaders log, and
+ // if the follower is just not starting and if leader's index is more than followers index
+ // then snapshot should be sent
+
+ if (LOG.isDebugEnabled()) {
+ LOG.debug("InitiateInstallSnapshot to follower:{}," +
+ "follower-nextIndex:{}, leader-snapshot-index:{}, " +
+ "leader-last-index:{}", followerId,
+ followerNextIndex, leaderSnapShotIndex, leaderLastIndex
+ );
}
- sendAppendEntriesToFollower(followerActor, followerNextIndex, entries);
+ // Send heartbeat to follower whenever install snapshot is initiated.
+ sendAppendEntriesToFollower(followerActor, followerLogInformation.getNextIndex(),
+ Collections.<ReplicatedLogEntry>emptyList(), followerId);
+ initiateCaptureSnapshot(followerId, followerNextIndex);
+
+ } else if(sendHeartbeat) {
+ //we send an AppendEntries, even if the follower is inactive
+ // in-order to update the followers timestamp, in case it becomes active again
+ sendAppendEntriesToFollower(followerActor, followerLogInformation.getNextIndex(),
+ Collections.<ReplicatedLogEntry>emptyList(), followerId);
}
+
}
}
}
private void sendAppendEntriesToFollower(ActorSelection followerActor, long followerNextIndex,
- List<ReplicatedLogEntry> entries) {
- followerActor.tell(
- new AppendEntries(currentTerm(), context.getId(),
- prevLogIndex(followerNextIndex),
- prevLogTerm(followerNextIndex), entries,
- context.getCommitIndex()).toSerializable(),
- actor()
- );
+ List<ReplicatedLogEntry> entries, String followerId) {
+ AppendEntries appendEntries = new AppendEntries(currentTerm(), context.getId(),
+ prevLogIndex(followerNextIndex),
+ prevLogTerm(followerNextIndex), entries,
+ context.getCommitIndex(), super.getReplicatedToAllIndex());
+
+ if(!entries.isEmpty()) {
+ LOG.debug("{}: Sending AppendEntries to follower {}: {}", context.getId(), followerId,
+ appendEntries);
+ }
+
+ followerActor.tell(appendEntries.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.
- *
* Install Snapshot works as follows
- * 1. Leader sends a InitiateInstallSnapshot message to self
- * 2. Leader then initiates the capture snapshot by sending a CaptureSnapshot message to actor
- * 3. RaftActor on receipt of the CaptureSnapshotReply (from Shard), stores the received snapshot in the replicated log
+ * 1. Leader initiates the capture snapshot by sending a CaptureSnapshot message to actor
+ * 2. RaftActor on receipt of the CaptureSnapshotReply (from Shard), stores the received snapshot in the replicated log
* and makes a call to Leader's handleMessage , with SendInstallSnapshot message.
- * 4. Leader , picks the snapshot from im-mem ReplicatedLog and sends it in chunks to the Follower
- * 5. On complete, Follower sends back a InstallSnapshotReply.
- * 6. On receipt of the InstallSnapshotReply for the last chunk, Leader marks the install complete for that follower
+ * 3. Leader , picks the snapshot from im-mem ReplicatedLog and sends it in chunks to the Follower
+ * 4. On complete, Follower sends back a InstallSnapshotReply.
+ * 5. On receipt of the InstallSnapshotReply for the last chunk, Leader marks the install complete for that follower
* and replenishes the memory by deleting the snapshot in Replicated log.
- *
+ * 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 installSnapshotIfNeeded() {
- for (Entry<String, FollowerLogInformation> e : followerToLog.entrySet()) {
- final ActorSelection followerActor = context.getPeerActorSelection(e.getKey());
-
- if (followerActor != null) {
- long nextIndex = e.getValue().getNextIndex();
-
- if (!context.getReplicatedLog().isPresent(nextIndex) &&
- context.getReplicatedLog().isInSnapshot(nextIndex)) {
- LOG.info("{}: {} follower needs a snapshot install", context.getId(), e.getKey());
- if (snapshot.isPresent()) {
- // if a snapshot is present in the memory, most likely another install is in progress
- // no need to capture snapshot
- sendSnapshotChunk(followerActor, e.getKey());
-
- } else {
- initiateCaptureSnapshot();
- //we just need 1 follower who would need snapshot to be installed.
- // when we have the snapshot captured, we would again check (in SendInstallSnapshot)
- // who needs an install and send to all who need
- break;
- }
+ 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);
+
+ } else if (!context.isSnapshotCaptureInitiated()) {
+
+ LOG.info("{}: Initiating Snapshot Capture to Install Snapshot, Leader:{}", context.getId(), getLeaderId());
+ ReplicatedLogEntry lastAppliedEntry = context.getReplicatedLog().get(context.getLastApplied());
+ long lastAppliedIndex = -1;
+ long lastAppliedTerm = -1;
+
+ if (lastAppliedEntry != null) {
+ lastAppliedIndex = lastAppliedEntry.getIndex();
+ lastAppliedTerm = lastAppliedEntry.getTerm();
+ } else if (context.getReplicatedLog().getSnapshotIndex() > -1) {
+ lastAppliedIndex = context.getReplicatedLog().getSnapshotIndex();
+ lastAppliedTerm = context.getReplicatedLog().getSnapshotTerm();
}
- }
- }
- }
-
- // on every install snapshot, we try to capture the snapshot.
- // Once a capture is going on, another one issued will get ignored by RaftActor.
- private void initiateCaptureSnapshot() {
- LOG.info("{}: Initiating Snapshot Capture to Install Snapshot, Leader:{}", context.getId(), getLeaderId());
- ReplicatedLogEntry lastAppliedEntry = context.getReplicatedLog().get(context.getLastApplied());
- long lastAppliedIndex = -1;
- long lastAppliedTerm = -1;
- if (lastAppliedEntry != null) {
- lastAppliedIndex = lastAppliedEntry.getIndex();
- lastAppliedTerm = lastAppliedEntry.getTerm();
- } else if (context.getReplicatedLog().getSnapshotIndex() > -1) {
- lastAppliedIndex = context.getReplicatedLog().getSnapshotIndex();
- lastAppliedTerm = context.getReplicatedLog().getSnapshotTerm();
+ boolean isInstallSnapshotInitiated = true;
+ long replicatedToAllIndex = super.getReplicatedToAllIndex();
+ ReplicatedLogEntry replicatedToAllEntry = context.getReplicatedLog().get(replicatedToAllIndex);
+ actor().tell(new CaptureSnapshot(lastIndex(), lastTerm(), lastAppliedIndex, lastAppliedTerm,
+ (replicatedToAllEntry != null ? replicatedToAllEntry.getIndex() : -1),
+ (replicatedToAllEntry != null ? replicatedToAllEntry.getTerm() : -1),
+ isInstallSnapshotInitiated), actor());
+ context.setSnapshotCaptureInitiated(true);
+ }
}
-
- boolean isInstallSnapshotInitiated = true;
- actor().tell(new CaptureSnapshot(lastIndex(), lastTerm(),
- lastAppliedIndex, lastAppliedTerm, isInstallSnapshotInitiated),
- actor());
}
private void sendSnapshotChunk(ActorSelection followerActor, String followerId) {
try {
if (snapshot.isPresent()) {
+ ByteString nextSnapshotChunk = getNextSnapshotChunk(followerId,snapshot.get());
+
+ // Note: the previous call to getNextSnapshotChunk has the side-effect of adding
+ // followerId to the followerToSnapshot map.
+ FollowerToSnapshot followerToSnapshot = mapFollowerToSnapshot.get(followerId);
+
followerActor.tell(
new InstallSnapshot(currentTerm(), context.getId(),
context.getReplicatedLog().getSnapshotIndex(),
context.getReplicatedLog().getSnapshotTerm(),
- getNextSnapshotChunk(followerId,snapshot.get()),
- mapFollowerToSnapshot.get(followerId).incrementChunkIndex(),
- mapFollowerToSnapshot.get(followerId).getTotalChunks(),
- Optional.of(mapFollowerToSnapshot.get(followerId).getLastChunkHashCode())
+ nextSnapshotChunk,
+ followerToSnapshot.incrementChunkIndex(),
+ followerToSnapshot.getTotalChunks(),
+ Optional.of(followerToSnapshot.getLastChunkHashCode())
).toSerializable(),
actor()
);
LOG.info("{}: InstallSnapshot sent to follower {}, Chunk: {}/{}",
context.getId(), followerActor.path(),
- mapFollowerToSnapshot.get(followerId).getChunkIndex(),
- mapFollowerToSnapshot.get(followerId).getTotalChunks());
+ followerToSnapshot.getChunkIndex(),
+ followerToSnapshot.getTotalChunks());
}
} catch (IOException e) {
- LOG.error(e, "{}: InstallSnapshot failed for Leader.", context.getId());
+ LOG.error("{}: InstallSnapshot failed for Leader.", context.getId(), e);
}
}
private void sendHeartBeat() {
if (!followerToLog.isEmpty()) {
- sendAppendEntries();
+ sendAppendEntries(context.getConfigParams().getHeartBeatInterval().toMillis());
}
}
Code Review / controller.git / blobdiff