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%2FFollower.java;h=e4d42661de3a9612d558e29685c55bf195d9a331;hb=refs%2Fchanges%2F35%2F41535%2F2;hp=a9d1b8233e5aa2301998375652fea36fe48442ee;hpb=23b10ec4ddfdd9348c2abe7dbcfbed3b49db3dc6;p=controller.git

diff --git a/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/Follower.java b/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/Follower.java
index a9d1b8233e..e4d42661de 100644
--- a/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/Follower.java
+++ b/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/Follower.java
@@ -11,8 +11,8 @@ package org.opendaylight.controller.cluster.raft.behaviors;
 import akka.actor.ActorRef;
 import akka.japi.Procedure;
 import com.google.common.annotations.VisibleForTesting;
-import com.google.common.base.Preconditions;
 import java.util.ArrayList;
+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;
@@ -65,12 +65,10 @@ public class Follower extends AbstractRaftActorBehavior {
 
         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(ElectionTimeout.INSTANCE, actor());
+        } else {
+            scheduleElection(electionDuration());
         }
     }
 
@@ -80,8 +78,8 @@ public class Follower extends AbstractRaftActorBehavior {
     }
 
     @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
@@ -99,28 +97,11 @@ public class Follower extends AbstractRaftActorBehavior {
             return true;
         }
 
-        ReplicatedLogEntry previousEntry = context.getReplicatedLog()
-                .get(index);
-
-        return previousEntry != null;
+        ReplicatedLogEntry entry = context.getReplicatedLog().get(index);
+        return entry != null;
 
     }
 
-    private long getLogEntryTerm(long index){
-        if(index == context.getReplicatedLog().getSnapshotIndex()){
-            return context.getReplicatedLog().getSnapshotTerm();
-        }
-
-        ReplicatedLogEntry previousEntry = context.getReplicatedLog()
-                .get(index);
-
-        if(previousEntry != null){
-            return previousEntry.getTerm();
-        }
-
-        return -1;
-    }
-
     private void updateInitialSyncStatus(long currentLeaderCommit, String leaderId){
         initialSyncStatusTracker.update(leaderId, currentLeaderCommit, context.getCommitIndex());
     }
@@ -186,14 +167,20 @@ public class Follower extends AbstractRaftActorBehavior {
                 // 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;
                     }
 
@@ -203,7 +190,18 @@ public class Follower extends AbstractRaftActorBehavior {
                                 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,
@@ -214,8 +212,8 @@ public class Follower extends AbstractRaftActorBehavior {
             }
 
             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++) {
@@ -350,6 +348,8 @@ public class Follower extends AbstractRaftActorBehavior {
                 LOG.debug("{}: Received ElectionTimeout - switching to Candidate", logName());
                 return internalSwitchBehavior(RaftState.Candidate);
             } else {
+                setLeaderId(null);
+                scheduleElection(electionDuration());
                 return this;
             }
         }
@@ -411,7 +411,7 @@ public class Follower extends AbstractRaftActorBehavior {
                         installSnapshot.getLastIncludedTerm(),
                         context.getTermInformation().getCurrentTerm(),
                         context.getTermInformation().getVotedFor(),
-                        context.getPeerServerInfo(true));
+                        installSnapshot.getServerConfig().orNull());
 
                 ApplySnapshot.Callback applySnapshotCallback = new ApplySnapshot.Callback() {
                     @Override