X-Git-Url: https://git.opendaylight.org/gerrit/gitweb?a=blobdiff_plain;f=opendaylight%2Fmd-sal%2Fsal-akka-raft%2Fsrc%2Fmain%2Fjava%2Forg%2Fopendaylight%2Fcontroller%2Fcluster%2Fraft%2Fbehaviors%2FAbstractRaftActorBehavior.java;h=b1560a5648b283e028ae0dc96e4267d92c6f438f;hb=2a31c2cacb9ad8f015a49708261ea93d256f0f60;hp=167082711d82b46c61e90e8311473d051e06461c;hpb=a0c5aba42aa36337ff1c6760175918b786897c9e;p=controller.git
diff --git a/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/AbstractRaftActorBehavior.java b/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/AbstractRaftActorBehavior.java
index 167082711d..45671ea31e 100644
--- a/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/AbstractRaftActorBehavior.java
+++ b/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/AbstractRaftActorBehavior.java
@@ -10,20 +10,23 @@ package org.opendaylight.controller.cluster.raft.behaviors;
import akka.actor.ActorRef;
import akka.actor.Cancellable;
+import java.util.Random;
+import java.util.concurrent.TimeUnit;
+import org.opendaylight.controller.cluster.raft.ClientRequestTracker;
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.ElectionTimeout;
+import org.opendaylight.controller.cluster.raft.SerializationUtils;
+import org.opendaylight.controller.cluster.raft.base.messages.ApplyJournalEntries;
+import org.opendaylight.controller.cluster.raft.base.messages.ApplyState;
+import org.opendaylight.controller.cluster.raft.base.messages.ElectionTimeout;
import org.opendaylight.controller.cluster.raft.messages.AppendEntries;
import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
-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.slf4j.Logger;
import scala.concurrent.duration.FiniteDuration;
-import java.util.Random;
-import java.util.concurrent.TimeUnit;
-
/**
* Abstract class that represents the behavior of a RaftActor
*
@@ -36,41 +39,59 @@ import java.util.concurrent.TimeUnit;
*/
public abstract class AbstractRaftActorBehavior implements RaftActorBehavior {
+ protected static final ElectionTimeout ELECTION_TIMEOUT = new ElectionTimeout();
+
/**
* Information about the RaftActor whose behavior this class represents
*/
protected final RaftActorContext context;
/**
- * The maximum election time variance
- */
- private static final int ELECTION_TIME_MAX_VARIANCE = 100;
-
- /**
- * The interval at which a heart beat message will be sent to the remote
- * RaftActor
- *
- * Since this is set to 100 milliseconds the Election timeout should be
- * at least 200 milliseconds
+ *
*/
- protected static final FiniteDuration HEART_BEAT_INTERVAL =
- new FiniteDuration(100, TimeUnit.MILLISECONDS);
+ protected final Logger LOG;
/**
- * The interval in which a new election would get triggered if no leader is found
+ *
*/
- private static final long ELECTION_TIME_INTERVAL =
- HEART_BEAT_INTERVAL.toMillis() * 2;
+ private Cancellable electionCancel = null;
/**
*
*/
+ protected String leaderId = null;
- private Cancellable electionCancel = null;
+ private long replicatedToAllIndex = -1;
+ private final String logName;
- protected AbstractRaftActorBehavior(RaftActorContext context) {
+ private final RaftState state;
+
+ protected AbstractRaftActorBehavior(RaftActorContext context, RaftState state) {
this.context = context;
+ this.state = state;
+ this.LOG = context.getLogger();
+
+ logName = String.format("%s (%s)", context.getId(), state);
+ }
+
+ @Override
+ public RaftState state() {
+ return state;
+ }
+
+ public String logName() {
+ return logName;
+ }
+
+ @Override
+ public void setReplicatedToAllIndex(long replicatedToAllIndex) {
+ this.replicatedToAllIndex = replicatedToAllIndex;
+ }
+
+ @Override
+ public long getReplicatedToAllIndex() {
+ return replicatedToAllIndex;
}
/**
@@ -83,77 +104,39 @@ public abstract class AbstractRaftActorBehavior implements RaftActorBehavior {
*
* @param sender The actor that sent this message
* @param appendEntries The AppendEntries message
- * @param suggestedState The state that the RaftActor should be in based
- * on the base class's processing of the AppendEntries
- * message
* @return
*/
- protected abstract RaftState handleAppendEntries(ActorRef sender,
- AppendEntries appendEntries, RaftState suggestedState);
+ protected abstract RaftActorBehavior handleAppendEntries(ActorRef sender,
+ AppendEntries appendEntries);
- protected RaftState appendEntries(ActorRef sender,
- AppendEntries appendEntries, RaftState raftState){
+ /**
+ * appendEntries first processes the AppendEntries message and then
+ * delegates handling to a specific behavior
+ *
+ * @param sender
+ * @param appendEntries
+ * @return
+ */
+ protected RaftActorBehavior appendEntries(ActorRef sender,
+ AppendEntries appendEntries) {
// 1. Reply false if term < currentTerm (§5.1)
- if(appendEntries.getTerm() < currentTerm()){
- sender.tell(new AppendEntriesReply(currentTerm(), false), actor());
- return state();
- }
-
- // 2. Reply false if log doesnât contain an entry at prevLogIndex
- // whose term matches prevLogTerm (§5.3)
- ReplicatedLogEntry previousEntry = context.getReplicatedLog()
- .get(appendEntries.getPrevLogIndex());
-
- if(previousEntry == null || previousEntry.getTerm() != appendEntries.getPrevLogTerm()){
- sender.tell(new AppendEntriesReply(currentTerm(), false), actor());
- return state();
- }
-
- if(appendEntries.getEntries() != null) {
- // 3. If an existing entry conflicts with a new one (same index
- // but different terms), delete the existing entry and all that
- // follow it (§5.3)
- int addEntriesFrom = 0;
- for (int i = 0;
- i < appendEntries.getEntries().size(); i++, addEntriesFrom++) {
- ReplicatedLogEntry newEntry = context.getReplicatedLog()
- .get(i + 1);
-
- if (newEntry != null && newEntry.getTerm() == appendEntries.getEntries().get(i).getTerm()){
- break;
- }
- if (newEntry != null && newEntry.getTerm() != appendEntries
- .getEntries().get(i).getTerm()) {
- context.getReplicatedLog().removeFrom(i + 1);
- break;
- }
- }
-
- // 4. Append any new entries not already in the log
- for (int i = addEntriesFrom;
- i < appendEntries.getEntries().size(); i++) {
- context.getReplicatedLog()
- .append(appendEntries.getEntries().get(i));
+ if (appendEntries.getTerm() < currentTerm()) {
+ if(LOG.isDebugEnabled()) {
+ LOG.debug("{}: Cannot append entries because sender term {} is less than {}",
+ logName(), appendEntries.getTerm(), currentTerm());
}
- }
-
- // 5. If leaderCommit > commitIndex, set commitIndex =
- // min(leaderCommit, index of last new entry)
- context.setCommitIndex(Math.min(appendEntries.getLeaderCommit(),
- context.getReplicatedLog().last().getIndex()));
-
- // If commitIndex > lastApplied: increment lastApplied, apply
- // log[lastApplied] to state machine (§5.3)
- if (appendEntries.getLeaderCommit() > context.getLastApplied()) {
- applyLogToStateMachine(appendEntries.getLeaderCommit());
+ sender.tell(
+ new AppendEntriesReply(context.getId(), currentTerm(), false,
+ lastIndex(), lastTerm()), actor()
+ );
+ return this;
}
- sender.tell(new AppendEntriesReply(currentTerm(), true), actor());
- return handleAppendEntries(sender, appendEntries, raftState);
+ return handleAppendEntries(sender, appendEntries);
}
/**
@@ -166,17 +149,22 @@ public abstract class AbstractRaftActorBehavior implements RaftActorBehavior {
*
* @param sender The actor that sent this message
* @param appendEntriesReply The AppendEntriesReply message
- * @param suggestedState The state that the RaftActor should be in based
- * on the base class's processing of the
- * AppendEntriesReply message
* @return
*/
+ protected abstract RaftActorBehavior handleAppendEntriesReply(ActorRef sender,
+ AppendEntriesReply appendEntriesReply);
- protected abstract RaftState handleAppendEntriesReply(ActorRef sender,
- AppendEntriesReply appendEntriesReply, RaftState suggestedState);
+ /**
+ * requestVote handles the RequestVote message. This logic is common
+ * for all behaviors
+ *
+ * @param sender
+ * @param requestVote
+ * @return
+ */
+ protected RaftActorBehavior requestVote(ActorRef sender, RequestVote requestVote) {
- protected RaftState requestVote(ActorRef sender,
- RequestVote requestVote, RaftState suggestedState) {
+ LOG.debug("{}: In requestVote: {}", logName(), requestVote);
boolean grantVote = false;
@@ -201,20 +189,24 @@ public abstract class AbstractRaftActorBehavior implements RaftActorBehavior {
if (requestVote.getLastLogTerm() > lastTerm()) {
candidateLatest = true;
} else if ((requestVote.getLastLogTerm() == lastTerm())
- && requestVote.getLastLogIndex() >= lastTerm()) {
+ && requestVote.getLastLogIndex() >= lastIndex()) {
candidateLatest = true;
}
if (candidateLatest) {
grantVote = true;
- context.getTermInformation().update(requestVote.getTerm(),
+ context.getTermInformation().updateAndPersist(requestVote.getTerm(),
requestVote.getCandidateId());
}
}
- sender.tell(new RequestVoteReply(currentTerm(), grantVote), actor());
+ RequestVoteReply reply = new RequestVoteReply(currentTerm(), grantVote);
+
+ LOG.debug("{}: requestVote returning: {}", logName(), reply);
- return suggestedState;
+ sender.tell(reply, actor());
+
+ return this;
}
/**
@@ -227,102 +219,279 @@ public abstract class AbstractRaftActorBehavior implements RaftActorBehavior {
*
* @param sender The actor that sent this message
* @param requestVoteReply The RequestVoteReply message
- * @param suggestedState The state that the RaftActor should be in based
- * on the base class's processing of the RequestVote
- * message
* @return
*/
-
- protected abstract RaftState handleRequestVoteReply(ActorRef sender,
- RequestVoteReply requestVoteReply, RaftState suggestedState);
+ protected abstract RaftActorBehavior handleRequestVoteReply(ActorRef sender,
+ RequestVoteReply requestVoteReply);
/**
- * @return The derived class should return the state that corresponds to
- * it's behavior
+ * Creates a random election duration
+ *
+ * @return
*/
- protected abstract RaftState state();
-
protected FiniteDuration electionDuration() {
- long variance = new Random().nextInt(ELECTION_TIME_MAX_VARIANCE);
- return new FiniteDuration(ELECTION_TIME_INTERVAL + variance,
- TimeUnit.MILLISECONDS);
+ long variance = new Random().nextInt(context.getConfigParams().getElectionTimeVariance());
+ return context.getConfigParams().getElectionTimeOutInterval().$plus(
+ new FiniteDuration(variance, TimeUnit.MILLISECONDS));
}
- protected void scheduleElection(FiniteDuration interval) {
-
+ /**
+ * stop the scheduled election
+ */
+ protected void stopElection() {
if (electionCancel != null && !electionCancel.isCancelled()) {
electionCancel.cancel();
}
+ }
+
+ /**
+ * schedule a new election
+ *
+ * @param interval
+ */
+ protected void scheduleElection(FiniteDuration interval) {
+ stopElection();
// Schedule an election. When the scheduler triggers an ElectionTimeout
// message is sent to itself
electionCancel =
context.getActorSystem().scheduler().scheduleOnce(interval,
- context.getActor(), new ElectionTimeout(),
+ context.getActor(), ELECTION_TIMEOUT,
context.getActorSystem().dispatcher(), context.getActor());
}
+ /**
+ * Get the current term
+ * @return
+ */
protected long currentTerm() {
return context.getTermInformation().getCurrentTerm();
}
+ /**
+ * Get the candidate for whom we voted in the current term
+ * @return
+ */
protected String votedFor() {
return context.getTermInformation().getVotedFor();
}
+ /**
+ * Get the actor associated with this behavior
+ * @return
+ */
protected ActorRef actor() {
return context.getActor();
}
+ /**
+ * Get the term from the last entry in the log
+ *
+ * @return
+ */
protected long lastTerm() {
- return context.getReplicatedLog().last().getTerm();
+ return context.getReplicatedLog().lastTerm();
}
+ /**
+ * Get the index from the last entry in the log
+ *
+ * @return
+ */
protected long lastIndex() {
- return context.getReplicatedLog().last().getIndex();
+ return context.getReplicatedLog().lastIndex();
}
+ /**
+ * Find the client request tracker for a specific logIndex
+ *
+ * @param logIndex
+ * @return
+ */
+ protected ClientRequestTracker findClientRequestTracker(long logIndex) {
+ return null;
+ }
- @Override
- public RaftState handleMessage(ActorRef sender, Object message) {
- RaftState raftState = state();
- if (message instanceof RaftRPC) {
- raftState = applyTerm((RaftRPC) message);
+ /**
+ * Find the client request tracker for a specific logIndex
+ *
+ * @param logIndex
+ * @return
+ */
+ protected ClientRequestTracker removeClientRequestTracker(long logIndex) {
+ return null;
+ }
+
+
+ /**
+ * Find the log index from the previous to last entry in the log
+ *
+ * @return
+ */
+ protected long prevLogIndex(long index){
+ ReplicatedLogEntry prevEntry =
+ context.getReplicatedLog().get(index - 1);
+ if (prevEntry != null) {
+ return prevEntry.getIndex();
}
+ return -1;
+ }
+
+ /**
+ * Find the log term from the previous to last entry in the log
+ * @return
+ */
+ protected long prevLogTerm(long index){
+ ReplicatedLogEntry prevEntry =
+ context.getReplicatedLog().get(index - 1);
+ if (prevEntry != null) {
+ return prevEntry.getTerm();
+ }
+ return -1;
+ }
+
+ /**
+ * Apply the provided index to the state machine
+ *
+ * @param index a log index that is known to be committed
+ */
+ protected void applyLogToStateMachine(final long index) {
+ long newLastApplied = context.getLastApplied();
+ // Now maybe we apply to the state machine
+ for (long i = context.getLastApplied() + 1;
+ i < index + 1; i++) {
+ ActorRef clientActor = null;
+ String identifier = null;
+ ClientRequestTracker tracker = removeClientRequestTracker(i);
+
+ if (tracker != null) {
+ clientActor = tracker.getClientActor();
+ identifier = tracker.getIdentifier();
+ }
+ ReplicatedLogEntry replicatedLogEntry =
+ context.getReplicatedLog().get(i);
+
+ if (replicatedLogEntry != null) {
+ // Send a local message to the local RaftActor (it's derived class to be
+ // specific to apply the log to it's index)
+ actor().tell(new ApplyState(clientActor, identifier,
+ replicatedLogEntry), actor());
+ newLastApplied = i;
+ } else {
+ //if one index is not present in the log, no point in looping
+ // around as the rest wont be present either
+ LOG.warn(
+ "{}: Missing index {} from log. Cannot apply state. Ignoring {} to {}",
+ logName(), i, i, index);
+ break;
+ }
+ }
+ if(LOG.isDebugEnabled()) {
+ LOG.debug("{}: Setting last applied to {}", logName(), newLastApplied);
+ }
+ context.setLastApplied(newLastApplied);
+
+ // send a message to persist a ApplyLogEntries marker message into akka's persistent journal
+ // will be used during recovery
+ //in case if the above code throws an error and this message is not sent, it would be fine
+ // as the append entries received later would initiate add this message to the journal
+ actor().tell(new ApplyJournalEntries(context.getLastApplied()), actor());
+ }
+
+ protected Object fromSerializableMessage(Object serializable){
+ return SerializationUtils.fromSerializable(serializable);
+ }
+
+ @Override
+ public RaftActorBehavior handleMessage(ActorRef sender, Object message) {
if (message instanceof AppendEntries) {
- raftState = appendEntries(sender, (AppendEntries) message,
- raftState);
+ return appendEntries(sender, (AppendEntries) message);
} else if (message instanceof AppendEntriesReply) {
- raftState =
- handleAppendEntriesReply(sender, (AppendEntriesReply) message,
- raftState);
+ return handleAppendEntriesReply(sender, (AppendEntriesReply) message);
} else if (message instanceof RequestVote) {
- raftState =
- requestVote(sender, (RequestVote) message, raftState);
+ return requestVote(sender, (RequestVote) message);
} else if (message instanceof RequestVoteReply) {
- raftState =
- handleRequestVoteReply(sender, (RequestVoteReply) message,
- raftState);
+ return handleRequestVoteReply(sender, (RequestVoteReply) message);
+ }
+ return this;
+ }
+
+ @Override public String getLeaderId() {
+ return leaderId;
+ }
+
+ protected RaftActorBehavior switchBehavior(RaftActorBehavior behavior) {
+ LOG.info("{} :- Switching from behavior {} to {}", logName(), this.state(), behavior.state());
+ try {
+ close();
+ } catch (Exception e) {
+ LOG.error("{}: Failed to close behavior : {}", logName(), this.state(), e);
}
- return raftState;
+
+ return behavior;
}
- private RaftState applyTerm(RaftRPC rpc) {
- // 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().update(rpc.getTerm(), null);
- return RaftState.Follower;
+ protected int getMajorityVoteCount(int numPeers) {
+ // Votes are required from a majority of the peers including self.
+ // The numMajority field therefore stores a calculated value
+ // of the number of votes required for this candidate to win an
+ // election based on it's known peers.
+ // If a peer was added during normal operation and raft replicas
+ // came to know about them then the new peer would also need to be
+ // taken into consideration when calculating this value.
+ // Here are some examples for what the numMajority would be for n
+ // peers
+ // 0 peers = 1 numMajority -: (0 + 1) / 2 + 1 = 1
+ // 2 peers = 2 numMajority -: (2 + 1) / 2 + 1 = 2
+ // 4 peers = 3 numMajority -: (4 + 1) / 2 + 1 = 3
+
+ int numMajority = 0;
+ if (numPeers > 0) {
+ int self = 1;
+ numMajority = (numPeers + self) / 2 + 1;
}
- return state();
+ return numMajority;
+
}
- private void applyLogToStateMachine(long index) {
- // Send a local message to the local RaftActor (it's derived class to be
- // specific to apply the log to it's index)
- context.setLastApplied(index);
+
+ /**
+ * Performs a snapshot with no capture on the replicated log.
+ * It clears the log from the supplied index or last-applied-1 which ever is minimum.
+ *
+ * @param snapshotCapturedIndex
+ */
+ protected void performSnapshotWithoutCapture(final long snapshotCapturedIndex) {
+ // we would want to keep the lastApplied as its used while capturing snapshots
+ long lastApplied = context.getLastApplied();
+ long tempMin = Math.min(snapshotCapturedIndex, (lastApplied > -1 ? lastApplied - 1 : -1));
+
+ if(LOG.isTraceEnabled()) {
+ LOG.trace("{}: performSnapshotWithoutCapture: snapshotCapturedIndex: {}, lastApplied: {}, tempMin: {}",
+ logName, snapshotCapturedIndex, lastApplied, tempMin);
+ }
+
+ if (tempMin > -1 && context.getReplicatedLog().isPresent(tempMin)) {
+ LOG.debug("{}: fakeSnapshot purging log to {} for term {}", logName(), tempMin,
+ context.getTermInformation().getCurrentTerm());
+
+ //use the term of the temp-min, since we check for isPresent, entry will not be null
+ ReplicatedLogEntry entry = context.getReplicatedLog().get(tempMin);
+ context.getReplicatedLog().snapshotPreCommit(tempMin, entry.getTerm());
+ context.getReplicatedLog().snapshotCommit();
+ setReplicatedToAllIndex(tempMin);
+ } else if(tempMin > getReplicatedToAllIndex()) {
+ // It's possible a follower was lagging and an install snapshot advanced its match index past
+ // the current replicatedToAllIndex. Since the follower is now caught up we should advance the
+ // replicatedToAllIndex (to tempMin). The fact that tempMin wasn't found in the log is likely
+ // due to a previous snapshot triggered by the memory threshold exceeded, in that case we
+ // trim the log to the last applied index even if previous entries weren't replicated to all followers.
+ setReplicatedToAllIndex(tempMin);
+ }
}
+ protected String getId(){
+ return context.getId();
+ }
}