Add RaftActorServerConfigurationSupport.raftActor
[controller.git] / opendaylight / md-sal / sal-akka-raft / src / test / java / org / opendaylight / controller / cluster / raft / RaftActorServerConfigurationSupportTest.java
index 77f40cd7c15038d3ac92ffbcd27fdf0bb9652ee3..0e29a3a031e016b218a5c95c11e404aa00cb36f1 100644 (file)
@@ -8,8 +8,10 @@
 package org.opendaylight.controller.cluster.raft;
 
 import static org.junit.Assert.assertEquals;
+import static org.opendaylight.controller.cluster.raft.utils.MessageCollectorActor.assertNoneMatching;
 import static org.opendaylight.controller.cluster.raft.utils.MessageCollectorActor.clearMessages;
 import static org.opendaylight.controller.cluster.raft.utils.MessageCollectorActor.expectFirstMatching;
+import static org.opendaylight.controller.cluster.raft.utils.MessageCollectorActor.expectMatching;
 import akka.actor.ActorRef;
 import akka.actor.Props;
 import akka.actor.UntypedActor;
@@ -19,7 +21,9 @@ import akka.testkit.TestActorRef;
 import com.google.common.base.Optional;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Maps;
+import com.google.common.collect.Sets;
 import java.util.Collections;
+import java.util.List;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import org.junit.After;
@@ -27,15 +31,27 @@ import org.junit.Before;
 import org.junit.Test;
 import org.opendaylight.controller.cluster.DataPersistenceProvider;
 import org.opendaylight.controller.cluster.NonPersistentDataProvider;
+import org.opendaylight.controller.cluster.raft.ServerConfigurationPayload.ServerInfo;
+import org.opendaylight.controller.cluster.raft.base.messages.ApplySnapshot;
+import org.opendaylight.controller.cluster.raft.base.messages.ApplyState;
 import org.opendaylight.controller.cluster.raft.base.messages.CaptureSnapshotReply;
+import org.opendaylight.controller.cluster.raft.base.messages.InitiateCaptureSnapshot;
+import org.opendaylight.controller.cluster.raft.behaviors.AbstractLeader;
 import org.opendaylight.controller.cluster.raft.behaviors.Follower;
 import org.opendaylight.controller.cluster.raft.behaviors.Leader;
 import org.opendaylight.controller.cluster.raft.messages.AddServer;
 import org.opendaylight.controller.cluster.raft.messages.AddServerReply;
 import org.opendaylight.controller.cluster.raft.messages.AppendEntries;
+import org.opendaylight.controller.cluster.raft.messages.InstallSnapshot;
+import org.opendaylight.controller.cluster.raft.messages.RemoveServer;
+import org.opendaylight.controller.cluster.raft.messages.RemoveServerReply;
 import org.opendaylight.controller.cluster.raft.messages.ServerChangeStatus;
+import org.opendaylight.controller.cluster.raft.messages.ServerRemoved;
+import org.opendaylight.controller.cluster.raft.messages.UnInitializedFollowerSnapshotReply;
 import org.opendaylight.controller.cluster.raft.policy.DisableElectionsRaftPolicy;
 import org.opendaylight.controller.cluster.raft.utils.ForwardMessageToBehaviorActor;
+import org.opendaylight.controller.cluster.raft.utils.InMemoryJournal;
+import org.opendaylight.controller.cluster.raft.utils.InMemorySnapshotStore;
 import org.opendaylight.controller.cluster.raft.utils.MessageCollectorActor;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -50,6 +66,7 @@ public class RaftActorServerConfigurationSupportTest extends AbstractActorTest {
     static final String LEADER_ID = "leader";
     static final String FOLLOWER_ID = "follower";
     static final String NEW_SERVER_ID = "new-server";
+    static final String NEW_SERVER_ID2 = "new-server2";
     private static final Logger LOG = LoggerFactory.getLogger(RaftActorServerConfigurationSupportTest.class);
     private static final DataPersistenceProvider NO_PERSISTENCE = new NonPersistentDataProvider();
 
@@ -59,23 +76,39 @@ public class RaftActorServerConfigurationSupportTest extends AbstractActorTest {
             Props.create(ForwardMessageToBehaviorActor.class).withDispatcher(Dispatchers.DefaultDispatcherId()),
             actorFactory.generateActorId(FOLLOWER_ID));
 
-    private final TestActorRef<ForwardMessageToBehaviorActor> newServerActor = actorFactory.createTestActor(
-            Props.create(ForwardMessageToBehaviorActor.class).withDispatcher(Dispatchers.DefaultDispatcherId()),
-            actorFactory.generateActorId(NEW_SERVER_ID));
+    private TestActorRef<MockNewFollowerRaftActor> newFollowerRaftActor;
+    private TestActorRef<MessageCollectorActor> newFollowerCollectorActor;
+    private RaftActorContext newFollowerActorContext;
 
-    private RaftActorContext newServerActorContext;
     private final JavaTestKit testKit = new JavaTestKit(getSystem());
 
     @Before
     public void setup() {
+        InMemoryJournal.clear();
+        InMemorySnapshotStore.clear();
+
+        DefaultConfigParamsImpl configParams = newFollowerConfigParams();
+
+        newFollowerCollectorActor = actorFactory.createTestActor(
+                MessageCollectorActor.props().withDispatcher(Dispatchers.DefaultDispatcherId()),
+                actorFactory.generateActorId(NEW_SERVER_ID + "Collector"));
+        newFollowerRaftActor = actorFactory.createTestActor(MockNewFollowerRaftActor.props(
+                configParams, newFollowerCollectorActor).withDispatcher(Dispatchers.DefaultDispatcherId()),
+                actorFactory.generateActorId(NEW_SERVER_ID));
+
+        try {
+            newFollowerActorContext = newFollowerRaftActor.underlyingActor().getRaftActorContext();
+        } catch (Exception e) {
+            newFollowerActorContext = newFollowerRaftActor.underlyingActor().getRaftActorContext();
+        }
+    }
+
+    private static DefaultConfigParamsImpl newFollowerConfigParams() {
         DefaultConfigParamsImpl configParams = new DefaultConfigParamsImpl();
         configParams.setHeartBeatInterval(new FiniteDuration(100, TimeUnit.MILLISECONDS));
         configParams.setElectionTimeoutFactor(100000);
         configParams.setCustomRaftPolicyImplementationClass(DisableElectionsRaftPolicy.class.getName());
-        newServerActorContext = new RaftActorContextImpl(newServerActor, newServerActor.underlyingActor().getContext(),
-                NEW_SERVER_ID, new ElectionTermImpl(NO_PERSISTENCE, NEW_SERVER_ID, LOG), -1, -1,
-                Maps.<String, String>newHashMap(), configParams, NO_PERSISTENCE, LOG);
-        newServerActorContext.setReplicatedLog(new MockRaftActorContext.MockReplicatedLogBuilder().build());
+        return configParams;
     }
 
     @After
@@ -84,19 +117,16 @@ public class RaftActorServerConfigurationSupportTest extends AbstractActorTest {
     }
 
     @Test
-    public void testAddServerWithFollower() throws Exception {
+    public void testAddServerWithExistingFollower() throws Exception {
         RaftActorContext followerActorContext = newFollowerContext(FOLLOWER_ID, followerActor);
         followerActorContext.setReplicatedLog(new MockRaftActorContext.MockReplicatedLogBuilder().createEntries(
                 0, 3, 1).build());
-        followerActorContext.setCommitIndex(3);
-        followerActorContext.setLastApplied(3);
+        followerActorContext.setCommitIndex(2);
+        followerActorContext.setLastApplied(2);
 
         Follower follower = new Follower(followerActorContext);
         followerActor.underlyingActor().setBehavior(follower);
 
-        Follower newServer = new Follower(newServerActorContext);
-        newServerActor.underlyingActor().setBehavior(newServer);
-
         TestActorRef<MockLeaderRaftActor> leaderActor = actorFactory.createTestActor(
                 MockLeaderRaftActor.props(ImmutableMap.of(FOLLOWER_ID, followerActor.path().toString()),
                         followerActorContext).withDispatcher(Dispatchers.DefaultDispatcherId()),
@@ -107,31 +137,427 @@ public class RaftActorServerConfigurationSupportTest extends AbstractActorTest {
         clearMessages(followerActor);
 
         MockLeaderRaftActor leaderRaftActor = leaderActor.underlyingActor();
+        TestActorRef<MessageCollectorActor> leaderCollectorActor = newLeaderCollectorActor(leaderRaftActor);
+
+        leaderActor.tell(new AddServer(NEW_SERVER_ID, newFollowerRaftActor.path().toString(), true), testKit.getRef());
+
+        // Leader should install snapshot - capture and verify ApplySnapshot contents
+
+        ApplySnapshot applySnapshot = expectFirstMatching(newFollowerCollectorActor, ApplySnapshot.class);
+        @SuppressWarnings("unchecked")
+        List<Object> snapshotState = (List<Object>) MockRaftActor.toObject(applySnapshot.getSnapshot().getState());
+        assertEquals("Snapshot state", snapshotState, leaderRaftActor.getState());
+
+        AddServerReply addServerReply = testKit.expectMsgClass(JavaTestKit.duration("5 seconds"), AddServerReply.class);
+        assertEquals("getStatus", ServerChangeStatus.OK, addServerReply.getStatus());
+        assertEquals("getLeaderHint", LEADER_ID, addServerReply.getLeaderHint());
+
+        // Verify ServerConfigurationPayload entry in leader's log
+
+        expectFirstMatching(leaderCollectorActor, ApplyState.class);
+        RaftActorContext leaderActorContext = leaderRaftActor.getRaftActorContext();
+        assertEquals("Leader journal last index", 3, leaderActorContext.getReplicatedLog().lastIndex());
+        assertEquals("Leader commit index", 3, leaderActorContext.getCommitIndex());
+        assertEquals("Leader last applied index", 3, leaderActorContext.getLastApplied());
+        verifyServerConfigurationPayloadEntry(leaderActorContext.getReplicatedLog(), votingServer(LEADER_ID),
+                votingServer(FOLLOWER_ID), votingServer(NEW_SERVER_ID));
+
+        // Verify ServerConfigurationPayload entry in both followers
+
+        expectFirstMatching(followerActor, ApplyState.class);
+        assertEquals("Follower journal last index", 3, followerActorContext.getReplicatedLog().lastIndex());
+        verifyServerConfigurationPayloadEntry(followerActorContext.getReplicatedLog(), votingServer(LEADER_ID),
+                votingServer(FOLLOWER_ID), votingServer(NEW_SERVER_ID));
+
+        expectFirstMatching(newFollowerCollectorActor, ApplyState.class);
+        assertEquals("New follower journal last index", 3, newFollowerActorContext.getReplicatedLog().lastIndex());
+        verifyServerConfigurationPayloadEntry(newFollowerActorContext.getReplicatedLog(), votingServer(LEADER_ID),
+                votingServer(FOLLOWER_ID), votingServer(NEW_SERVER_ID));
+
+        // Verify new server config was applied in both followers
+
+        assertEquals("Follower peers", Sets.newHashSet(LEADER_ID, NEW_SERVER_ID), followerActorContext.getPeerIds());
+
+        assertEquals("New follower peers", Sets.newHashSet(LEADER_ID, FOLLOWER_ID), newFollowerActorContext.getPeerIds());
+
+        expectFirstMatching(newFollowerCollectorActor, ApplyState.class);
+        expectFirstMatching(followerActor, ApplyState.class);
+
+        assertEquals("Follower commit index", 3, followerActorContext.getCommitIndex());
+        assertEquals("Follower last applied index", 3, followerActorContext.getLastApplied());
+        assertEquals("New follower commit index", 3, newFollowerActorContext.getCommitIndex());
+        assertEquals("New follower last applied index", 3, newFollowerActorContext.getLastApplied());
+
+        List<ReplicatedLogImplEntry> persistedLogEntries = InMemoryJournal.get(LEADER_ID, ReplicatedLogImplEntry.class);
+        assertEquals("Leader ReplicatedLogImplEntry entries", 1, persistedLogEntries.size());
+        ReplicatedLogImplEntry logEntry = persistedLogEntries.get(0);
+        assertEquals("Leader ReplicatedLogImplEntry getTerm", 1, logEntry.getTerm());
+        assertEquals("Leader ReplicatedLogImplEntry getIndex", 3, logEntry.getIndex());
+        assertEquals("Leader ReplicatedLogImplEntry getData", ServerConfigurationPayload.class, logEntry.getData().getClass());
+
+        persistedLogEntries = InMemoryJournal.get(NEW_SERVER_ID, ReplicatedLogImplEntry.class);
+        assertEquals("New follower ReplicatedLogImplEntry entries", 1, persistedLogEntries.size());
+        logEntry = persistedLogEntries.get(0);
+        assertEquals("New follower ReplicatedLogImplEntry getTerm", 1, logEntry.getTerm());
+        assertEquals("New follower ReplicatedLogImplEntry getIndex", 3, logEntry.getIndex());
+        assertEquals("New follower ReplicatedLogImplEntry getData", ServerConfigurationPayload.class,
+                logEntry.getData().getClass());
+    }
+
+    @Test
+    public void testAddServerWithNoExistingFollower() throws Exception {
+        RaftActorContext initialActorContext = new MockRaftActorContext();
+        initialActorContext.setCommitIndex(1);
+        initialActorContext.setLastApplied(1);
+        initialActorContext.setReplicatedLog(new MockRaftActorContext.MockReplicatedLogBuilder().createEntries(
+                0, 2, 1).build());
+
+        TestActorRef<MockLeaderRaftActor> leaderActor = actorFactory.createTestActor(
+                MockLeaderRaftActor.props(ImmutableMap.<String, String>of(),
+                        initialActorContext).withDispatcher(Dispatchers.DefaultDispatcherId()),
+                actorFactory.generateActorId(LEADER_ID));
+
+        MockLeaderRaftActor leaderRaftActor = leaderActor.underlyingActor();
+        RaftActorContext leaderActorContext = leaderRaftActor.getRaftActorContext();
+
+        TestActorRef<MessageCollectorActor> leaderCollectorActor = newLeaderCollectorActor(leaderRaftActor);
+
+        leaderActor.tell(new AddServer(NEW_SERVER_ID, newFollowerRaftActor.path().toString(), true), testKit.getRef());
+
+        // Leader should install snapshot - capture and verify ApplySnapshot contents
+
+        ApplySnapshot applySnapshot = expectFirstMatching(newFollowerCollectorActor, ApplySnapshot.class);
+        @SuppressWarnings("unchecked")
+        List<Object> snapshotState = (List<Object>) MockRaftActor.toObject(applySnapshot.getSnapshot().getState());
+        assertEquals("Snapshot state", snapshotState, leaderRaftActor.getState());
+
+        AddServerReply addServerReply = testKit.expectMsgClass(JavaTestKit.duration("5 seconds"), AddServerReply.class);
+        assertEquals("getStatus", ServerChangeStatus.OK, addServerReply.getStatus());
+        assertEquals("getLeaderHint", LEADER_ID, addServerReply.getLeaderHint());
+
+        // Verify ServerConfigurationPayload entry in leader's log
 
-        leaderActor.tell(new AddServer(NEW_SERVER_ID, newServerActor.path().toString(), true), testKit.getRef());
+        expectFirstMatching(leaderCollectorActor, ApplyState.class);
+        assertEquals("Leader journal last index", 2, leaderActorContext.getReplicatedLog().lastIndex());
+        assertEquals("Leader commit index", 2, leaderActorContext.getCommitIndex());
+        assertEquals("Leader last applied index", 2, leaderActorContext.getLastApplied());
+        verifyServerConfigurationPayloadEntry(leaderActorContext.getReplicatedLog(), votingServer(LEADER_ID),
+                votingServer(NEW_SERVER_ID));
 
-        // leader should install snapshot - capture and verify ApplySnapshot contents
-//        ApplySnapshot applySnapshot = expectFirstMatching(followerActor, ApplySnapshot.class);
-//        List<Object> snapshotState = (List<Object>) MockRaftActor.toObject(applySnapshot.getSnapshot().getState());
-//        assertEquals("Snapshot state", snapshotState, leaderRaftActor.getState());
+        // Verify ServerConfigurationPayload entry in the new follower
 
-        // leader should replicate new server config to both followers
-//         expectFirstMatching(followerActor, AppendEntries.class);
-//         expectFirstMatching(newServerActor, AppendEntries.class);
+        expectFirstMatching(newFollowerCollectorActor, ApplyState.class);
+        assertEquals("New follower journal last index", 2, newFollowerActorContext.getReplicatedLog().lastIndex());
+        verifyServerConfigurationPayloadEntry(newFollowerActorContext.getReplicatedLog(), votingServer(LEADER_ID),
+                votingServer(NEW_SERVER_ID));
 
-        // verify ServerConfigurationPayload entry in leader's log
-//        RaftActorContext leaderActorContext = leaderRaftActor.getRaftActorContext();
-//        assertEquals("Leader journal log size", 4, leaderActorContext.getReplicatedLog().size());
-//        assertEquals("Leader journal last index", 3, leaderActorContext.getReplicatedLog().lastIndex());
-//        ReplicatedLogEntry logEntry = leaderActorContext.getReplicatedLog().get(
-//                leaderActorContext.getReplicatedLog().lastIndex());
-        // verify logEntry contents
+        // Verify new server config was applied in the new follower
 
-        // Also verify ServerConfigurationPayload entry in both followers
+        assertEquals("New follower peers", Sets.newHashSet(LEADER_ID), newFollowerActorContext.getPeerIds());
+    }
+
+    @Test
+    public void testAddServersAsNonVoting() throws Exception {
+        RaftActorContext initialActorContext = new MockRaftActorContext();
+
+        TestActorRef<MockLeaderRaftActor> leaderActor = actorFactory.createTestActor(
+                MockLeaderRaftActor.props(ImmutableMap.<String, String>of(),
+                        initialActorContext).withDispatcher(Dispatchers.DefaultDispatcherId()),
+                actorFactory.generateActorId(LEADER_ID));
+
+        MockLeaderRaftActor leaderRaftActor = leaderActor.underlyingActor();
+        RaftActorContext leaderActorContext = leaderRaftActor.getRaftActorContext();
+
+        TestActorRef<MessageCollectorActor> leaderCollectorActor = newLeaderCollectorActor(leaderRaftActor);
+
+        leaderActor.tell(new AddServer(NEW_SERVER_ID, newFollowerRaftActor.path().toString(), false), testKit.getRef());
 
         AddServerReply addServerReply = testKit.expectMsgClass(JavaTestKit.duration("5 seconds"), AddServerReply.class);
         assertEquals("getStatus", ServerChangeStatus.OK, addServerReply.getStatus());
         assertEquals("getLeaderHint", LEADER_ID, addServerReply.getLeaderHint());
+
+        // Verify ServerConfigurationPayload entry in leader's log
+
+        expectFirstMatching(leaderCollectorActor, ApplyState.class);
+
+        assertEquals("Leader journal last index", 0, leaderActorContext.getReplicatedLog().lastIndex());
+        assertEquals("Leader commit index", 0, leaderActorContext.getCommitIndex());
+        assertEquals("Leader last applied index", 0, leaderActorContext.getLastApplied());
+        verifyServerConfigurationPayloadEntry(leaderActorContext.getReplicatedLog(), votingServer(LEADER_ID),
+                nonVotingServer(NEW_SERVER_ID));
+
+        // Verify ServerConfigurationPayload entry in the new follower
+
+        expectFirstMatching(newFollowerCollectorActor, ApplyState.class);
+        assertEquals("New follower journal last index", 0, newFollowerActorContext.getReplicatedLog().lastIndex());
+        verifyServerConfigurationPayloadEntry(newFollowerActorContext.getReplicatedLog(), votingServer(LEADER_ID),
+                nonVotingServer(NEW_SERVER_ID));
+
+        // Verify new server config was applied in the new follower
+
+        assertEquals("New follower peers", Sets.newHashSet(LEADER_ID), newFollowerActorContext.getPeerIds());
+
+        assertNoneMatching(newFollowerCollectorActor, InstallSnapshot.class, 500);
+
+        // Add another non-voting server.
+
+        clearMessages(leaderCollectorActor);
+
+        RaftActorContext follower2ActorContext = newFollowerContext(NEW_SERVER_ID2, followerActor);
+        Follower newFollower2 = new Follower(follower2ActorContext);
+        followerActor.underlyingActor().setBehavior(newFollower2);
+
+        leaderActor.tell(new AddServer(NEW_SERVER_ID2, followerActor.path().toString(), false), testKit.getRef());
+
+        addServerReply = testKit.expectMsgClass(JavaTestKit.duration("5 seconds"), AddServerReply.class);
+        assertEquals("getStatus", ServerChangeStatus.OK, addServerReply.getStatus());
+        assertEquals("getLeaderHint", LEADER_ID, addServerReply.getLeaderHint());
+
+        expectFirstMatching(leaderCollectorActor, ApplyState.class);
+        assertEquals("Leader journal last index", 1, leaderActorContext.getReplicatedLog().lastIndex());
+        assertEquals("Leader commit index", 1, leaderActorContext.getCommitIndex());
+        assertEquals("Leader last applied index", 1, leaderActorContext.getLastApplied());
+        verifyServerConfigurationPayloadEntry(leaderActorContext.getReplicatedLog(),
+                votingServer(LEADER_ID), nonVotingServer(NEW_SERVER_ID), nonVotingServer(NEW_SERVER_ID2));
+    }
+
+    @Test
+    public void testAddServerWithOperationInProgress() throws Exception {
+        RaftActorContext initialActorContext = new MockRaftActorContext();
+
+        TestActorRef<MockLeaderRaftActor> leaderActor = actorFactory.createTestActor(
+                MockLeaderRaftActor.props(ImmutableMap.<String, String>of(),
+                        initialActorContext).withDispatcher(Dispatchers.DefaultDispatcherId()),
+                actorFactory.generateActorId(LEADER_ID));
+
+        MockLeaderRaftActor leaderRaftActor = leaderActor.underlyingActor();
+        RaftActorContext leaderActorContext = leaderRaftActor.getRaftActorContext();
+
+        TestActorRef<MessageCollectorActor> leaderCollectorActor = newLeaderCollectorActor(leaderRaftActor);
+
+        RaftActorContext follower2ActorContext = newFollowerContext(NEW_SERVER_ID2, followerActor);
+        Follower newFollower2 = new Follower(follower2ActorContext);
+        followerActor.underlyingActor().setBehavior(newFollower2);
+
+        MockNewFollowerRaftActor newFollowerRaftActorInstance = newFollowerRaftActor.underlyingActor();
+        newFollowerRaftActorInstance.setDropMessageOfType(InstallSnapshot.SERIALIZABLE_CLASS);
+
+        leaderActor.tell(new AddServer(NEW_SERVER_ID, newFollowerRaftActor.path().toString(), true), testKit.getRef());
+
+        // Wait for leader's install snapshot and capture it
+
+        InstallSnapshot installSnapshot = expectFirstMatching(newFollowerCollectorActor, InstallSnapshot.class);
+
+        // Send a second AddServer - should get queued
+        JavaTestKit testKit2 = new JavaTestKit(getSystem());
+        leaderActor.tell(new AddServer(NEW_SERVER_ID2, followerActor.path().toString(), false), testKit2.getRef());
+
+        // Continue the first AddServer
+        newFollowerRaftActorInstance.setDropMessageOfType(null);
+        newFollowerRaftActor.tell(installSnapshot, leaderActor);
+
+        // Verify both complete successfully
+        AddServerReply addServerReply = testKit.expectMsgClass(JavaTestKit.duration("5 seconds"), AddServerReply.class);
+        assertEquals("getStatus", ServerChangeStatus.OK, addServerReply.getStatus());
+
+        addServerReply = testKit2.expectMsgClass(JavaTestKit.duration("5 seconds"), AddServerReply.class);
+        assertEquals("getStatus", ServerChangeStatus.OK, addServerReply.getStatus());
+
+        // Verify ServerConfigurationPayload entries in leader's log
+
+        expectMatching(leaderCollectorActor, ApplyState.class, 2);
+        assertEquals("Leader journal last index", 1, leaderActorContext.getReplicatedLog().lastIndex());
+        assertEquals("Leader commit index", 1, leaderActorContext.getCommitIndex());
+        assertEquals("Leader last applied index", 1, leaderActorContext.getLastApplied());
+        verifyServerConfigurationPayloadEntry(leaderActorContext.getReplicatedLog(),
+                votingServer(LEADER_ID), votingServer(NEW_SERVER_ID), nonVotingServer(NEW_SERVER_ID2));
+
+        // Verify ServerConfigurationPayload entry in the new follower
+
+        expectMatching(newFollowerCollectorActor, ApplyState.class, 2);
+        assertEquals("New follower peers", Sets.newHashSet(LEADER_ID, NEW_SERVER_ID2),
+               newFollowerActorContext.getPeerIds());
+    }
+
+    @Test
+    public void testAddServerWithPriorSnapshotInProgress() throws Exception {
+        RaftActorContext initialActorContext = new MockRaftActorContext();
+
+        TestActorRef<MockLeaderRaftActor> leaderActor = actorFactory.createTestActor(
+                MockLeaderRaftActor.props(ImmutableMap.<String, String>of(),
+                        initialActorContext).withDispatcher(Dispatchers.DefaultDispatcherId()),
+                actorFactory.generateActorId(LEADER_ID));
+
+        MockLeaderRaftActor leaderRaftActor = leaderActor.underlyingActor();
+        RaftActorContext leaderActorContext = leaderRaftActor.getRaftActorContext();
+
+        TestActorRef<MessageCollectorActor> leaderCollectorActor = newLeaderCollectorActor(leaderRaftActor);
+
+        // Drop commit message for now to delay snapshot completion
+        leaderRaftActor.setDropMessageOfType(String.class);
+
+        leaderActor.tell(new InitiateCaptureSnapshot(), leaderActor);
+
+        String commitMsg = expectFirstMatching(leaderCollectorActor, String.class);
+
+        leaderActor.tell(new AddServer(NEW_SERVER_ID, newFollowerRaftActor.path().toString(), true), testKit.getRef());
+
+        leaderRaftActor.setDropMessageOfType(null);
+        leaderActor.tell(commitMsg, leaderActor);
+
+        AddServerReply addServerReply = testKit.expectMsgClass(JavaTestKit.duration("5 seconds"), AddServerReply.class);
+        assertEquals("getStatus", ServerChangeStatus.OK, addServerReply.getStatus());
+        assertEquals("getLeaderHint", LEADER_ID, addServerReply.getLeaderHint());
+
+        expectFirstMatching(newFollowerCollectorActor, ApplySnapshot.class);
+
+        // Verify ServerConfigurationPayload entry in leader's log
+
+        expectFirstMatching(leaderCollectorActor, ApplyState.class);
+        assertEquals("Leader journal last index", 0, leaderActorContext.getReplicatedLog().lastIndex());
+        assertEquals("Leader commit index", 0, leaderActorContext.getCommitIndex());
+        assertEquals("Leader last applied index", 0, leaderActorContext.getLastApplied());
+        verifyServerConfigurationPayloadEntry(leaderActorContext.getReplicatedLog(), votingServer(LEADER_ID),
+                votingServer(NEW_SERVER_ID));
+    }
+
+    @Test
+    public void testAddServerWithPriorSnapshotCompleteTimeout() throws Exception {
+        RaftActorContext initialActorContext = new MockRaftActorContext();
+
+        TestActorRef<MockLeaderRaftActor> leaderActor = actorFactory.createTestActor(
+                MockLeaderRaftActor.props(ImmutableMap.<String, String>of(),
+                        initialActorContext).withDispatcher(Dispatchers.DefaultDispatcherId()),
+                actorFactory.generateActorId(LEADER_ID));
+
+        MockLeaderRaftActor leaderRaftActor = leaderActor.underlyingActor();
+        RaftActorContext leaderActorContext = leaderRaftActor.getRaftActorContext();
+
+        ((DefaultConfigParamsImpl)leaderActorContext.getConfigParams()).setElectionTimeoutFactor(1);
+
+        // Drop commit message so the snapshot doesn't complete.
+        leaderRaftActor.setDropMessageOfType(String.class);
+
+        leaderActor.tell(new InitiateCaptureSnapshot(), leaderActor);
+
+        leaderActor.tell(new AddServer(NEW_SERVER_ID, newFollowerRaftActor.path().toString(), true), testKit.getRef());
+
+        AddServerReply addServerReply = testKit.expectMsgClass(JavaTestKit.duration("5 seconds"), AddServerReply.class);
+        assertEquals("getStatus", ServerChangeStatus.TIMEOUT, addServerReply.getStatus());
+
+        assertEquals("Leader peers size", 0, leaderActorContext.getPeerIds().size());
+    }
+
+    @Test
+    public void testAddServerWithLeaderChangeBeforePriorSnapshotComplete() throws Exception {
+        RaftActorContext initialActorContext = new MockRaftActorContext();
+
+        TestActorRef<MockLeaderRaftActor> leaderActor = actorFactory.createTestActor(
+                MockLeaderRaftActor.props(ImmutableMap.<String, String>of(),
+                        initialActorContext).withDispatcher(Dispatchers.DefaultDispatcherId()),
+                actorFactory.generateActorId(LEADER_ID));
+
+        MockLeaderRaftActor leaderRaftActor = leaderActor.underlyingActor();
+        RaftActorContext leaderActorContext = leaderRaftActor.getRaftActorContext();
+        ((DefaultConfigParamsImpl)leaderActorContext.getConfigParams()).setElectionTimeoutFactor(100);
+
+        TestActorRef<MessageCollectorActor> leaderCollectorActor = newLeaderCollectorActor(leaderRaftActor);
+
+        // Drop the commit message so the snapshot doesn't complete yet.
+        leaderRaftActor.setDropMessageOfType(String.class);
+
+        leaderActor.tell(new InitiateCaptureSnapshot(), leaderActor);
+
+        leaderActor.tell(new AddServer(NEW_SERVER_ID, newFollowerRaftActor.path().toString(), true), testKit.getRef());
+
+        String commitMsg = expectFirstMatching(leaderCollectorActor, String.class);
+
+        // Change the leader behavior to follower
+        leaderActor.tell(new Follower(leaderActorContext), leaderActor);
+
+        // Drop CaptureSnapshotReply in case install snapshot is incorrectly initiated after the prior
+        // snapshot completes. This will prevent the invalid snapshot from completing and fail the
+        // isCapturing assertion below.
+        leaderRaftActor.setDropMessageOfType(CaptureSnapshotReply.class);
+
+        // Complete the prior snapshot - this should be a no-op b/c it's no longer the leader
+        leaderActor.tell(commitMsg, leaderActor);
+
+        leaderActor.tell(new RaftActorServerConfigurationSupport.ServerOperationTimeout(NEW_SERVER_ID), leaderActor);
+
+        AddServerReply addServerReply = testKit.expectMsgClass(JavaTestKit.duration("5 seconds"), AddServerReply.class);
+        assertEquals("getStatus", ServerChangeStatus.NO_LEADER, addServerReply.getStatus());
+
+        assertEquals("Leader peers size", 0, leaderActorContext.getPeerIds().size());
+        assertEquals("isCapturing", false, leaderActorContext.getSnapshotManager().isCapturing());
+    }
+
+    @Test
+    public void testAddServerWithLeaderChangeDuringInstallSnapshot() throws Exception {
+        RaftActorContext initialActorContext = new MockRaftActorContext();
+
+        TestActorRef<MockLeaderRaftActor> leaderActor = actorFactory.createTestActor(
+                MockLeaderRaftActor.props(ImmutableMap.<String, String>of(),
+                        initialActorContext).withDispatcher(Dispatchers.DefaultDispatcherId()),
+                actorFactory.generateActorId(LEADER_ID));
+
+        MockLeaderRaftActor leaderRaftActor = leaderActor.underlyingActor();
+        RaftActorContext leaderActorContext = leaderRaftActor.getRaftActorContext();
+
+        ((DefaultConfigParamsImpl)leaderActorContext.getConfigParams()).setElectionTimeoutFactor(8);
+
+        TestActorRef<MessageCollectorActor> leaderCollectorActor = newLeaderCollectorActor(leaderRaftActor);
+
+        // Drop the UnInitializedFollowerSnapshotReply to delay it.
+        leaderRaftActor.setDropMessageOfType(UnInitializedFollowerSnapshotReply.class);
+
+        leaderActor.tell(new AddServer(NEW_SERVER_ID, newFollowerRaftActor.path().toString(), true), testKit.getRef());
+
+        UnInitializedFollowerSnapshotReply snapshotReply = expectFirstMatching(leaderCollectorActor,
+                UnInitializedFollowerSnapshotReply.class);
+
+        // Prevent election timeout when the leader switches to follower
+        ((DefaultConfigParamsImpl)leaderActorContext.getConfigParams()).setElectionTimeoutFactor(100);
+
+        // Change the leader behavior to follower
+        leaderActor.tell(new Follower(leaderActorContext), leaderActor);
+
+        // Send the captured UnInitializedFollowerSnapshotReply - should be a no-op
+        leaderRaftActor.setDropMessageOfType(null);
+        leaderActor.tell(snapshotReply, leaderActor);
+
+        AddServerReply addServerReply = testKit.expectMsgClass(JavaTestKit.duration("5 seconds"), AddServerReply.class);
+        assertEquals("getStatus", ServerChangeStatus.NO_LEADER, addServerReply.getStatus());
+
+        assertEquals("Leader peers size", 0, leaderActorContext.getPeerIds().size());
+    }
+
+    @Test
+    public void testAddServerWithInstallSnapshotTimeout() throws Exception {
+        RaftActorContext initialActorContext = new MockRaftActorContext();
+
+        TestActorRef<MockLeaderRaftActor> leaderActor = actorFactory.createTestActor(
+                MockLeaderRaftActor.props(ImmutableMap.<String, String>of(),
+                        initialActorContext).withDispatcher(Dispatchers.DefaultDispatcherId()),
+                actorFactory.generateActorId(LEADER_ID));
+
+        MockLeaderRaftActor leaderRaftActor = leaderActor.underlyingActor();
+        RaftActorContext leaderActorContext = leaderRaftActor.getRaftActorContext();
+        ((DefaultConfigParamsImpl)leaderActorContext.getConfigParams()).setElectionTimeoutFactor(1);
+
+        // Drop the InstallSnapshot message so it times out
+        newFollowerRaftActor.underlyingActor().setDropMessageOfType(InstallSnapshot.SERIALIZABLE_CLASS);
+
+        leaderActor.tell(new AddServer(NEW_SERVER_ID, newFollowerRaftActor.path().toString(), true), testKit.getRef());
+
+        leaderActor.tell(new UnInitializedFollowerSnapshotReply("bogus"), leaderActor);
+
+        AddServerReply addServerReply = testKit.expectMsgClass(JavaTestKit.duration("5 seconds"), AddServerReply.class);
+        assertEquals("getStatus", ServerChangeStatus.TIMEOUT, addServerReply.getStatus());
+
+        assertEquals("Leader peers size", 0, leaderActorContext.getPeerIds().size());
+        assertEquals("Leader followers size", 0,
+                ((AbstractLeader)leaderRaftActor.getCurrentBehavior()).getFollowerIds().size());
     }
 
     @Test
@@ -140,16 +566,88 @@ public class RaftActorServerConfigurationSupportTest extends AbstractActorTest {
         configParams.setHeartBeatInterval(new FiniteDuration(1, TimeUnit.DAYS));
 
         TestActorRef<MockRaftActor> noLeaderActor = actorFactory.createTestActor(
-                MockRaftActor.props(LEADER_ID, ImmutableMap.<String,String>of(FOLLOWER_ID, followerActor.path().toString()),
-                        Optional.<ConfigParams>of(configParams), NO_PERSISTENCE).withDispatcher(Dispatchers.DefaultDispatcherId()),
+                MockRaftActor.props(LEADER_ID, ImmutableMap.of(FOLLOWER_ID, followerActor.path().toString()),
+                        configParams, NO_PERSISTENCE).withDispatcher(Dispatchers.DefaultDispatcherId()),
                 actorFactory.generateActorId(LEADER_ID));
         noLeaderActor.underlyingActor().waitForInitializeBehaviorComplete();
 
-        noLeaderActor.tell(new AddServer(NEW_SERVER_ID, newServerActor.path().toString(), true), testKit.getRef());
+        noLeaderActor.tell(new AddServer(NEW_SERVER_ID, newFollowerRaftActor.path().toString(), true), testKit.getRef());
         AddServerReply addServerReply = testKit.expectMsgClass(JavaTestKit.duration("5 seconds"), AddServerReply.class);
         assertEquals("getStatus", ServerChangeStatus.NO_LEADER, addServerReply.getStatus());
     }
 
+    @Test
+    public void testAddServerWithNoConsensusReached() {
+        RaftActorContext initialActorContext = new MockRaftActorContext();
+
+        TestActorRef<MockLeaderRaftActor> leaderActor = actorFactory.createTestActor(
+                MockLeaderRaftActor.props(ImmutableMap.<String, String>of(),
+                        initialActorContext).withDispatcher(Dispatchers.DefaultDispatcherId()),
+                actorFactory.generateActorId(LEADER_ID));
+
+        MockLeaderRaftActor leaderRaftActor = leaderActor.underlyingActor();
+        RaftActorContext leaderActorContext = leaderRaftActor.getRaftActorContext();
+
+        TestActorRef<MessageCollectorActor> leaderCollectorActor = newLeaderCollectorActor(leaderRaftActor);
+
+        // Drop UnInitializedFollowerSnapshotReply initially
+        leaderRaftActor.setDropMessageOfType(UnInitializedFollowerSnapshotReply.class);
+
+        MockNewFollowerRaftActor newFollowerRaftActorInstance = newFollowerRaftActor.underlyingActor();
+        TestActorRef<MessageCollectorActor> newFollowerCollectorActor =
+                newCollectorActor(newFollowerRaftActorInstance, NEW_SERVER_ID);
+
+        // Drop AppendEntries to the new follower so consensus isn't reached
+        newFollowerRaftActorInstance.setDropMessageOfType(AppendEntries.class);
+
+        leaderActor.tell(new AddServer(NEW_SERVER_ID, newFollowerRaftActor.path().toString(), true), testKit.getRef());
+
+        // Capture the UnInitializedFollowerSnapshotReply
+        Object snapshotReply = expectFirstMatching(leaderCollectorActor, UnInitializedFollowerSnapshotReply.class);
+
+        // Send the UnInitializedFollowerSnapshotReply to resume the first request
+        leaderRaftActor.setDropMessageOfType(null);
+        leaderActor.tell(snapshotReply, leaderActor);
+
+        expectFirstMatching(newFollowerCollectorActor, AppendEntries.class);
+
+        // Send a second AddServer
+        leaderActor.tell(new AddServer(NEW_SERVER_ID2, "", false), testKit.getRef());
+
+        // The first AddServer should succeed with OK even though consensus wasn't reached
+        AddServerReply addServerReply = testKit.expectMsgClass(JavaTestKit.duration("5 seconds"), AddServerReply.class);
+        assertEquals("getStatus", ServerChangeStatus.OK, addServerReply.getStatus());
+        assertEquals("getLeaderHint", LEADER_ID, addServerReply.getLeaderHint());
+
+        // Verify ServerConfigurationPayload entry in leader's log
+        verifyServerConfigurationPayloadEntry(leaderActorContext.getReplicatedLog(), votingServer(LEADER_ID),
+                votingServer(NEW_SERVER_ID));
+
+        // The second AddServer should fail since consensus wasn't reached for the first
+        addServerReply = testKit.expectMsgClass(JavaTestKit.duration("5 seconds"), AddServerReply.class);
+        assertEquals("getStatus", ServerChangeStatus.PRIOR_REQUEST_CONSENSUS_TIMEOUT, addServerReply.getStatus());
+
+        // Re-send the second AddServer - should also fail
+        leaderActor.tell(new AddServer(NEW_SERVER_ID2, "", false), testKit.getRef());
+        addServerReply = testKit.expectMsgClass(JavaTestKit.duration("5 seconds"), AddServerReply.class);
+        assertEquals("getStatus", ServerChangeStatus.PRIOR_REQUEST_CONSENSUS_TIMEOUT, addServerReply.getStatus());
+    }
+
+    @Test
+    public void testAddServerWithExistingServer() {
+        RaftActorContext initialActorContext = new MockRaftActorContext();
+
+        TestActorRef<MockLeaderRaftActor> leaderActor = actorFactory.createTestActor(
+                MockLeaderRaftActor.props(ImmutableMap.of(FOLLOWER_ID, followerActor.path().toString()),
+                        initialActorContext).withDispatcher(Dispatchers.DefaultDispatcherId()),
+                actorFactory.generateActorId(LEADER_ID));
+
+        leaderActor.tell(new AddServer(FOLLOWER_ID, followerActor.path().toString(), true), testKit.getRef());
+
+        AddServerReply addServerReply = testKit.expectMsgClass(JavaTestKit.duration("5 seconds"), AddServerReply.class);
+        assertEquals("getStatus", ServerChangeStatus.ALREADY_EXISTS, addServerReply.getStatus());
+    }
+
     @Test
     public void testAddServerForwardedToLeader() {
         DefaultConfigParamsImpl configParams = new DefaultConfigParamsImpl();
@@ -160,33 +658,237 @@ public class RaftActorServerConfigurationSupportTest extends AbstractActorTest {
                 actorFactory.generateActorId(LEADER_ID));
 
         TestActorRef<MockRaftActor> followerRaftActor = actorFactory.createTestActor(
-                MockRaftActor.props(FOLLOWER_ID, ImmutableMap.<String,String>of(LEADER_ID, leaderActor.path().toString()),
-                        Optional.<ConfigParams>of(configParams), NO_PERSISTENCE).withDispatcher(Dispatchers.DefaultDispatcherId()),
+                MockRaftActor.props(FOLLOWER_ID, ImmutableMap.of(LEADER_ID, leaderActor.path().toString()),
+                        configParams, NO_PERSISTENCE).withDispatcher(Dispatchers.DefaultDispatcherId()),
                 actorFactory.generateActorId(FOLLOWER_ID));
         followerRaftActor.underlyingActor().waitForInitializeBehaviorComplete();
 
         followerRaftActor.tell(new AppendEntries(1, LEADER_ID, 0, 1, Collections.<ReplicatedLogEntry>emptyList(),
                 -1, -1, (short)0), leaderActor);
 
-        followerRaftActor.tell(new AddServer(NEW_SERVER_ID, newServerActor.path().toString(), true), testKit.getRef());
+        followerRaftActor.tell(new AddServer(NEW_SERVER_ID, newFollowerRaftActor.path().toString(), true), testKit.getRef());
         expectFirstMatching(leaderActor, AddServer.class);
     }
 
-    private RaftActorContext newFollowerContext(String id, TestActorRef<? extends UntypedActor> actor) {
+    @Test
+    public void testOnApplyState() {
+        DefaultConfigParamsImpl configParams = new DefaultConfigParamsImpl();
+        configParams.setHeartBeatInterval(new FiniteDuration(1, TimeUnit.DAYS));
+        TestActorRef<MockRaftActor> noLeaderActor = actorFactory.createTestActor(
+                MockRaftActor.props(LEADER_ID, ImmutableMap.of(FOLLOWER_ID, followerActor.path().toString()),
+                        configParams, NO_PERSISTENCE).withDispatcher(Dispatchers.DefaultDispatcherId()),
+                actorFactory.generateActorId(LEADER_ID));
+
+        RaftActorServerConfigurationSupport support = new RaftActorServerConfigurationSupport(noLeaderActor.underlyingActor());
+
+        ReplicatedLogEntry serverConfigEntry = new MockRaftActorContext.MockReplicatedLogEntry(1, 1,
+                new ServerConfigurationPayload(Collections.<ServerInfo>emptyList()));
+        boolean handled = support.handleMessage(new ApplyState(null, null, serverConfigEntry), ActorRef.noSender());
+        assertEquals("Message handled", true, handled);
+
+        ReplicatedLogEntry nonServerConfigEntry = new MockRaftActorContext.MockReplicatedLogEntry(1, 1,
+                new MockRaftActorContext.MockPayload("1"));
+        handled = support.handleMessage(new ApplyState(null, null, nonServerConfigEntry), ActorRef.noSender());
+        assertEquals("Message handled", false, handled);
+    }
+
+    @Test
+    public void testRemoveServerWithNoLeader() {
+        DefaultConfigParamsImpl configParams = new DefaultConfigParamsImpl();
+        configParams.setHeartBeatInterval(new FiniteDuration(1, TimeUnit.DAYS));
+
+        TestActorRef<MockRaftActor> leaderActor = actorFactory.createTestActor(
+                MockRaftActor.props(LEADER_ID, ImmutableMap.of(FOLLOWER_ID, followerActor.path().toString()),
+                        configParams, NO_PERSISTENCE).withDispatcher(Dispatchers.DefaultDispatcherId()),
+                actorFactory.generateActorId(LEADER_ID));
+        leaderActor.underlyingActor().waitForInitializeBehaviorComplete();
+
+        leaderActor.tell(new RemoveServer(FOLLOWER_ID), testKit.getRef());
+        RemoveServerReply removeServerReply = testKit.expectMsgClass(JavaTestKit.duration("5 seconds"), RemoveServerReply.class);
+        assertEquals("getStatus", ServerChangeStatus.NO_LEADER, removeServerReply.getStatus());
+    }
+
+    @Test
+    public void testRemoveServerNonExistentServer() {
+        RaftActorContext initialActorContext = new MockRaftActorContext();
+
+        TestActorRef<MockLeaderRaftActor> leaderActor = actorFactory.createTestActor(
+                MockLeaderRaftActor.props(ImmutableMap.of(FOLLOWER_ID, followerActor.path().toString()),
+                        initialActorContext).withDispatcher(Dispatchers.DefaultDispatcherId()),
+                actorFactory.generateActorId(LEADER_ID));
+
+        leaderActor.tell(new RemoveServer(NEW_SERVER_ID), testKit.getRef());
+        RemoveServerReply removeServerReply = testKit.expectMsgClass(JavaTestKit.duration("5 seconds"), RemoveServerReply.class);
+        assertEquals("getStatus", ServerChangeStatus.DOES_NOT_EXIST, removeServerReply.getStatus());
+    }
+
+    @Test
+    public void testRemoveServerSelf() {
+        RaftActorContext initialActorContext = new MockRaftActorContext();
+
+        TestActorRef<MockLeaderRaftActor> leaderActor = actorFactory.createTestActor(
+                MockLeaderRaftActor.props(ImmutableMap.of(FOLLOWER_ID, followerActor.path().toString()),
+                        initialActorContext).withDispatcher(Dispatchers.DefaultDispatcherId()),
+                actorFactory.generateActorId(LEADER_ID));
+
+        leaderActor.tell(new RemoveServer(LEADER_ID), testKit.getRef());
+        RemoveServerReply removeServerReply = testKit.expectMsgClass(JavaTestKit.duration("5 seconds"), RemoveServerReply.class);
+        assertEquals("getStatus", ServerChangeStatus.NOT_SUPPORTED, removeServerReply.getStatus());
+    }
+
+    @Test
+    public void testRemoveServerForwardToLeader() {
+        DefaultConfigParamsImpl configParams = new DefaultConfigParamsImpl();
+        configParams.setHeartBeatInterval(new FiniteDuration(1, TimeUnit.DAYS));
+        configParams.setCustomRaftPolicyImplementationClass(DisableElectionsRaftPolicy.class.getName());
+
+        RaftActorContext initialActorContext = new MockRaftActorContext();
+
+        TestActorRef<MockLeaderRaftActor> leaderActor = actorFactory.createTestActor(
+                MockLeaderRaftActor.props(ImmutableMap.<String, String>of(),
+                        initialActorContext).withDispatcher(Dispatchers.DefaultDispatcherId()),
+                actorFactory.generateActorId(LEADER_ID));
+
+        TestActorRef<MockRaftActor> followerRaftActor = actorFactory.createTestActor(
+                MockRaftActor.props(FOLLOWER_ID, ImmutableMap.of(LEADER_ID, leaderActor.path().toString()),
+                        configParams, NO_PERSISTENCE).withDispatcher(Dispatchers.DefaultDispatcherId()),
+                actorFactory.generateActorId(FOLLOWER_ID));
+
+
+        followerRaftActor.tell(new AppendEntries(1, LEADER_ID, 0, 1, Collections.<ReplicatedLogEntry>emptyList(),
+                -1, -1, (short) 0), leaderActor);
+
+        followerRaftActor.tell(new RemoveServer(LEADER_ID), testKit.getRef());
+        RemoveServerReply removeServerReply = testKit.expectMsgClass(JavaTestKit.duration("5 seconds"), RemoveServerReply.class);
+        assertEquals("getStatus", ServerChangeStatus.NOT_SUPPORTED, removeServerReply.getStatus());
+    }
+
+    @Test
+    public void testRemoveServer() {
+        DefaultConfigParamsImpl configParams = new DefaultConfigParamsImpl();
+        configParams.setHeartBeatInterval(new FiniteDuration(1, TimeUnit.DAYS));
+        configParams.setCustomRaftPolicyImplementationClass(DisableElectionsRaftPolicy.class.getName());
+
+        final String followerActorId = actorFactory.generateActorId(FOLLOWER_ID);
+        final String followerActorPath = actorFactory.createTestActorPath(followerActorId);
+        RaftActorContext initialActorContext = new MockRaftActorContext();
+
+        TestActorRef<MockLeaderRaftActor> leaderActor = actorFactory.createTestActor(
+                MockLeaderRaftActor.props(ImmutableMap.of(FOLLOWER_ID, followerActorPath),
+                        initialActorContext).withDispatcher(Dispatchers.DefaultDispatcherId()),
+                actorFactory.generateActorId(LEADER_ID));
+
+        TestActorRef<MessageCollectorActor> leaderCollector = newLeaderCollectorActor(leaderActor.underlyingActor());
+
+        TestActorRef<CollectingMockRaftActor> followerRaftActor = actorFactory.createTestActor(
+                CollectingMockRaftActor.props(FOLLOWER_ID, ImmutableMap.of(LEADER_ID, leaderActor.path().toString()),
+                        configParams, NO_PERSISTENCE).withDispatcher(Dispatchers.DefaultDispatcherId()),
+                followerActorId);
+
+        TestActorRef<MessageCollectorActor> collector =
+                actorFactory.createTestActor(MessageCollectorActor.props().withDispatcher(Dispatchers.DefaultDispatcherId()), actorFactory.generateActorId("collector"));
+
+        followerRaftActor.underlyingActor().setCollectorActor(collector);
+
+        leaderActor.tell(new RemoveServer(FOLLOWER_ID), testKit.getRef());
+        RemoveServerReply removeServerReply = testKit.expectMsgClass(JavaTestKit.duration("5 seconds"), RemoveServerReply.class);
+
+        assertEquals("getStatus", ServerChangeStatus.OK, removeServerReply.getStatus());
+
+        final ApplyState applyState = MessageCollectorActor.expectFirstMatching(leaderCollector, ApplyState.class);
+        assertEquals(0L, applyState.getReplicatedLogEntry().getIndex());
+        verifyServerConfigurationPayloadEntry(leaderActor.underlyingActor().getRaftActorContext().getReplicatedLog(), votingServer(LEADER_ID));
+
+        MessageCollectorActor.expectFirstMatching(collector, ServerRemoved.class);
+    }
+
+    private ServerInfo votingServer(String id) {
+        return new ServerInfo(id, true);
+    }
+
+    private ServerInfo nonVotingServer(String id) {
+        return new ServerInfo(id, false);
+    }
+
+    private TestActorRef<MessageCollectorActor> newLeaderCollectorActor(MockLeaderRaftActor leaderRaftActor) {
+        return newCollectorActor(leaderRaftActor, LEADER_ID);
+    }
+
+    private TestActorRef<MessageCollectorActor> newCollectorActor(AbstractMockRaftActor raftActor, String id) {
+        TestActorRef<MessageCollectorActor> collectorActor = actorFactory.createTestActor(
+                MessageCollectorActor.props().withDispatcher(Dispatchers.DefaultDispatcherId()),
+                actorFactory.generateActorId(id + "Collector"));
+        raftActor.setCollectorActor(collectorActor);
+        return collectorActor;
+    }
+
+    private static void verifyServerConfigurationPayloadEntry(ReplicatedLog log, ServerInfo... expected) {
+        ReplicatedLogEntry logEntry = log.get(log.lastIndex());
+        assertEquals("Last log entry payload class", ServerConfigurationPayload.class, logEntry.getData().getClass());
+        ServerConfigurationPayload payload = (ServerConfigurationPayload)logEntry.getData();
+        assertEquals("getNewServerConfig", Sets.newHashSet(expected), Sets.newHashSet(payload.getServerConfig()));
+    }
+
+    private static RaftActorContext newFollowerContext(String id, TestActorRef<? extends UntypedActor> actor) {
         DefaultConfigParamsImpl configParams = new DefaultConfigParamsImpl();
         configParams.setHeartBeatInterval(new FiniteDuration(100, TimeUnit.MILLISECONDS));
         configParams.setElectionTimeoutFactor(100000);
-        RaftActorContext followerActorContext = new RaftActorContextImpl(actor, actor.underlyingActor().getContext(),
-                id, new ElectionTermImpl(NO_PERSISTENCE, id, LOG), -1, -1,
-                ImmutableMap.of(LEADER_ID, ""), configParams, NO_PERSISTENCE, LOG);
+        ElectionTermImpl termInfo = new ElectionTermImpl(NO_PERSISTENCE, id, LOG);
+        termInfo.update(1, LEADER_ID);
+        return new RaftActorContextImpl(actor, actor.underlyingActor().getContext(),
+                id, termInfo, -1, -1, ImmutableMap.of(LEADER_ID, ""), configParams, NO_PERSISTENCE, LOG);
+    }
+
+    static abstract class AbstractMockRaftActor extends MockRaftActor {
+        private volatile TestActorRef<MessageCollectorActor> collectorActor;
+        private volatile Class<?> dropMessageOfType;
+
+        AbstractMockRaftActor(String id, Map<String, String> peerAddresses, Optional<ConfigParams> config,
+                DataPersistenceProvider dataPersistenceProvider, TestActorRef<MessageCollectorActor> collectorActor) {
+            super(builder().id(id).peerAddresses(peerAddresses).config(config.get()).
+                    dataPersistenceProvider(dataPersistenceProvider));
+            this.collectorActor = collectorActor;
+        }
+
+        void setDropMessageOfType(Class<?> dropMessageOfType) {
+            this.dropMessageOfType = dropMessageOfType;
+        }
+
+        void setCollectorActor(TestActorRef<MessageCollectorActor> collectorActor) {
+            this.collectorActor = collectorActor;
+        }
+
+        @Override
+        public void handleCommand(Object message) {
+            if(dropMessageOfType == null || !dropMessageOfType.equals(message.getClass())) {
+                super.handleCommand(message);
+            }
+
+            if(collectorActor != null) {
+                collectorActor.tell(message, getSender());
+            }
+        }
+    }
+
+    public static class CollectingMockRaftActor extends AbstractMockRaftActor {
+
+        CollectingMockRaftActor(String id, Map<String, String> peerAddresses, Optional<ConfigParams> config, DataPersistenceProvider dataPersistenceProvider, TestActorRef<MessageCollectorActor> collectorActor) {
+            super(id, peerAddresses, config, dataPersistenceProvider, collectorActor);
+        }
+
+        public static Props props(final String id, final Map<String, String> peerAddresses,
+                                  ConfigParams config, DataPersistenceProvider dataPersistenceProvider){
+
+            return Props.create(CollectingMockRaftActor.class, id, peerAddresses, Optional.of(config), dataPersistenceProvider, null);
+        }
 
-        return followerActorContext;
     }
 
-    public static class MockLeaderRaftActor extends MockRaftActor {
+    public static class MockLeaderRaftActor extends AbstractMockRaftActor {
         public MockLeaderRaftActor(Map<String, String> peerAddresses, ConfigParams config,
                 RaftActorContext fromContext) {
-            super(LEADER_ID, peerAddresses, Optional.of(config), NO_PERSISTENCE);
+            super(LEADER_ID, peerAddresses, Optional.of(config), NO_PERSISTENCE, null);
+            setPersistence(false);
 
             RaftActorContext context = getRaftActorContext();
             for(int i = 0; i < fromContext.getReplicatedLog().size(); i++) {
@@ -197,6 +899,8 @@ public class RaftActorServerConfigurationSupportTest extends AbstractActorTest {
 
             context.setCommitIndex(fromContext.getCommitIndex());
             context.setLastApplied(fromContext.getLastApplied());
+            context.getTermInformation().update(fromContext.getTermInformation().getCurrentTerm(),
+                    fromContext.getTermInformation().getVotedFor());
         }
 
         @Override
@@ -216,9 +920,20 @@ public class RaftActorServerConfigurationSupportTest extends AbstractActorTest {
 
         static Props props(Map<String, String> peerAddresses, RaftActorContext fromContext) {
             DefaultConfigParamsImpl configParams = new DefaultConfigParamsImpl();
-            configParams.setHeartBeatInterval(new FiniteDuration(1, TimeUnit.DAYS));
-            configParams.setElectionTimeoutFactor(100000);
+            configParams.setHeartBeatInterval(new FiniteDuration(100, TimeUnit.MILLISECONDS));
+            configParams.setElectionTimeoutFactor(10);
             return Props.create(MockLeaderRaftActor.class, peerAddresses, configParams, fromContext);
         }
     }
+
+    public static class MockNewFollowerRaftActor extends AbstractMockRaftActor {
+        public MockNewFollowerRaftActor(ConfigParams config, TestActorRef<MessageCollectorActor> collectorActor) {
+            super(NEW_SERVER_ID, Maps.<String, String>newHashMap(), Optional.of(config), null, collectorActor);
+            setPersistence(false);
+        }
+
+        static Props props(ConfigParams config, TestActorRef<MessageCollectorActor> collectorActor) {
+            return Props.create(MockNewFollowerRaftActor.class, config, collectorActor);
+        }
+    }
 }