opendaylight/md-sal/sal-akka-raft/src/test/java/org/opendaylight/controller/cluster/raft/ReplicationAndSnapshotsIntegrationTest.java

   1 /*
   2  * Copyright (c) 2015 Brocade Communications Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.controller.cluster.raft;
   9
  10 import static org.junit.Assert.assertEquals;
  11 import akka.persistence.SaveSnapshotSuccess;
  12 import com.google.common.collect.ImmutableMap;
  13 import java.util.List;
  14 import org.junit.Test;
  15 import org.opendaylight.controller.cluster.raft.MockRaftActorContext.MockPayload;
  16 import org.opendaylight.controller.cluster.raft.RaftActor.UpdateElectionTerm;
  17 import org.opendaylight.controller.cluster.raft.base.messages.ApplyJournalEntries;
  18 import org.opendaylight.controller.cluster.raft.base.messages.ApplyState;
  19 import org.opendaylight.controller.cluster.raft.base.messages.CaptureSnapshotReply;
  20 import org.opendaylight.controller.cluster.raft.messages.AppendEntries;
  21 import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
  22 import org.opendaylight.controller.cluster.raft.utils.InMemoryJournal;
  23 import org.opendaylight.controller.cluster.raft.utils.InMemorySnapshotStore;
  24 import org.opendaylight.controller.cluster.raft.utils.MessageCollectorActor;
  25
  26 /**
  27  * Tests replication and snapshots end-to-end using real RaftActors and behavior communication.
  28  *
  29  * @author Thomas Pantelis
  30  */
  31 public class ReplicationAndSnapshotsIntegrationTest extends AbstractRaftActorIntegrationTest {
  32
  33     private List<ReplicatedLogImplEntry> origLeaderJournal;
  34
  35     private MockPayload recoveredPayload0;
  36     private MockPayload recoveredPayload1;
  37     private MockPayload recoveredPayload2;
  38     private MockPayload payload3;
  39     private MockPayload payload4;
  40     private MockPayload payload5;
  41     private MockPayload payload6;
  42     private MockPayload payload7;
  43
  44     @Test
  45     public void runTest() throws Exception {
  46         testLog.info("testReplicationAndSnapshots starting");
  47
  48         // Setup the persistent journal for the leader. We'll start up with 3 journal log entries (one less
  49         // than the snapshotBatchCount).
  50         long seqId = 1;
  51         InMemoryJournal.addEntry(leaderId, seqId++, new UpdateElectionTerm(initialTerm, leaderId));
  52         recoveredPayload0 = new MockPayload("zero");
  53         InMemoryJournal.addEntry(leaderId, seqId++, new ReplicatedLogImplEntry(0, initialTerm, recoveredPayload0));
  54         recoveredPayload1 = new MockPayload("one");
  55         InMemoryJournal.addEntry(leaderId, seqId++, new ReplicatedLogImplEntry(1, initialTerm, recoveredPayload1));
  56         recoveredPayload2 = new MockPayload("two");
  57         InMemoryJournal.addEntry(leaderId, seqId++, new ReplicatedLogImplEntry(2, initialTerm, recoveredPayload2));
  58         InMemoryJournal.addEntry(leaderId, seqId++, new ApplyJournalEntries(2));
  59
  60         origLeaderJournal = InMemoryJournal.get(leaderId, ReplicatedLogImplEntry.class);
  61
  62         // Create the leader and 2 follower actors and verify initial syncing of the followers after leader
  63         // persistence recovery.
  64
  65         follower1Actor = newTestRaftActor(follower1Id, ImmutableMap.of(leaderId, testActorPath(leaderId),
  66                 follower2Id, testActorPath(follower2Id)), newFollowerConfigParams());
  67
  68         follower2Actor = newTestRaftActor(follower2Id, ImmutableMap.of(leaderId, testActorPath(leaderId),
  69                 follower1Id, testActorPath(follower1Id)), newFollowerConfigParams());
  70
  71         peerAddresses = ImmutableMap.<String, String>builder().
  72                 put(follower1Id, follower1Actor.path().toString()).
  73                 put(follower2Id, follower2Actor.path().toString()).build();
  74
  75         leaderConfigParams = newLeaderConfigParams();
  76         leaderActor = newTestRaftActor(leaderId, peerAddresses, leaderConfigParams);
  77
  78         follower1CollectorActor = follower1Actor.underlyingActor().collectorActor();
  79         follower2CollectorActor = follower2Actor.underlyingActor().collectorActor();
  80         leaderCollectorActor = leaderActor.underlyingActor().collectorActor();
  81
  82         leaderContext = leaderActor.underlyingActor().getRaftActorContext();
  83
  84         verifyLeaderRecoveryAndInitialization();
  85
  86         testFirstSnapshot();
  87
  88         testSubsequentReplications();
  89
  90         testSecondSnapshot();
  91
  92         testLeaderReinstatement();
  93
  94         testLog.info("testReplicationAndSnapshots ending");
  95     }
  96
  97     /**
  98      * Verify the expected leader is elected as the leader and verify initial syncing of the followers
  99      * from the leader's persistence recovery.
 100      */
 101     void verifyLeaderRecoveryAndInitialization() {
 102         testLog.info("verifyLeaderRecoveryAndInitialization starting");
 103
 104         waitUntilLeader(leaderActor);
 105
 106         currentTerm = leaderContext.getTermInformation().getCurrentTerm();
 107         assertEquals("Current term > " + initialTerm, true, currentTerm > initialTerm);
 108
 109         leader = leaderActor.underlyingActor().getCurrentBehavior();
 110
 111         // The followers should receive AppendEntries for each leader log entry that was recovered from
 112         // persistence and apply each one.
 113         List<ApplyState> applyStates = MessageCollectorActor.expectMatching(
 114                 follower1CollectorActor, ApplyState.class, 3);
 115         verifyApplyState(applyStates.get(0), null, null, initialTerm, 0, recoveredPayload0);
 116         verifyApplyState(applyStates.get(1), null, null, initialTerm, 1, recoveredPayload1);
 117         verifyApplyState(applyStates.get(2), null, null, initialTerm, 2, recoveredPayload2);
 118
 119         // Verify follower 1 applies a log entry for at least the last entry index.
 120         verifyApplyJournalEntries(follower1CollectorActor, 2);
 121
 122         applyStates = MessageCollectorActor.expectMatching(follower2CollectorActor, ApplyState.class, 3);
 123         verifyApplyState(applyStates.get(0), null, null, initialTerm, 0, recoveredPayload0);
 124         verifyApplyState(applyStates.get(1), null, null, initialTerm, 1, recoveredPayload1);
 125         verifyApplyState(applyStates.get(2), null, null, initialTerm, 2, recoveredPayload2);
 126
 127         // Verify follower 1]2 applies a log entry for at least the last entry index.
 128         verifyApplyJournalEntries(follower2CollectorActor, 2);
 129
 130         MessageCollectorActor.clearMessages(leaderCollectorActor);
 131         MessageCollectorActor.clearMessages(follower1CollectorActor);
 132         MessageCollectorActor.clearMessages(follower2CollectorActor);
 133
 134         // The leader should have performed fake snapshots due to the follower's AppendEntriesReplies and
 135         // trimmed the in-memory log so that only the last entry remains.
 136         assertEquals("Leader snapshot term", initialTerm, leaderContext.getReplicatedLog().getSnapshotTerm());
 137         assertEquals("Leader snapshot index", 1, leaderContext.getReplicatedLog().getSnapshotIndex());
 138         assertEquals("Leader journal log size", 1, leaderContext.getReplicatedLog().size());
 139         assertEquals("Leader journal last index", 2, leaderContext.getReplicatedLog().lastIndex());
 140         assertEquals("Leader commit index", 2, leaderContext.getCommitIndex());
 141         assertEquals("Leader last applied", 2, leaderContext.getLastApplied());
 142         assertEquals("Leader replicatedToAllIndex", 1, leader.getReplicatedToAllIndex());
 143
 144         // Verify the follower's persisted journal log.
 145         verifyPersistedJournal(follower1Id, origLeaderJournal);
 146         verifyPersistedJournal(follower2Id, origLeaderJournal);
 147
 148         MessageCollectorActor.clearMessages(leaderCollectorActor);
 149         MessageCollectorActor.clearMessages(follower1CollectorActor);
 150         MessageCollectorActor.clearMessages(follower2CollectorActor);
 151
 152         testLog.info("verifyLeaderRecoveryAndInitialization ending");
 153     }
 154
 155     /**
 156      * Send a payload to the TestRaftActor to persist and replicate. Since snapshotBatchCount is set to
 157      * 4 and we already have 3 entries in the journal log, this should initiate a snapshot. In this
 158      * scenario, the follower consensus and application of state is delayed until after the snapshot
 159      * completes.
 160      * @throws Exception
 161      */
 162     private void testFirstSnapshot() throws Exception {
 163         testLog.info("testFirstSnapshot starting");
 164
 165         expSnapshotState.add(recoveredPayload0);
 166         expSnapshotState.add(recoveredPayload1);
 167         expSnapshotState.add(recoveredPayload2);
 168
 169         // Delay the consensus by temporarily dropping the AppendEntries to both followers.
 170         follower1Actor.underlyingActor().startDropMessages(AppendEntries.class);
 171         follower2Actor.underlyingActor().startDropMessages(AppendEntries.class);
 172
 173         // Send the payload.
 174         payload3 = sendPayloadData(leaderActor, "three");
 175
 176         // Wait for snapshot complete.
 177         MessageCollectorActor.expectFirstMatching(leaderCollectorActor, SaveSnapshotSuccess.class);
 178
 179         // The snapshot index should not be advanced nor the log trimmed because replicatedToAllIndex
 180         // is behind due the followers not being replicated yet via AppendEntries.
 181         assertEquals("Leader snapshot term", initialTerm, leaderContext.getReplicatedLog().getSnapshotTerm());
 182         assertEquals("Leader snapshot index", 1, leaderContext.getReplicatedLog().getSnapshotIndex());
 183         assertEquals("Leader journal log size", 2, leaderContext.getReplicatedLog().size());
 184         assertEquals("Leader journal last index", 3, leaderContext.getReplicatedLog().lastIndex());
 185
 186         // Verify the persisted snapshot in the leader. This should reflect the advanced snapshot index as
 187         // the last applied log entry (2) even though the leader hasn't yet advanced its cached snapshot index.
 188         List<Snapshot> persistedSnapshots = InMemorySnapshotStore.getSnapshots(leaderId, Snapshot.class);
 189         assertEquals("Persisted snapshots size", 1, persistedSnapshots.size());
 190         verifySnapshot("Persisted", persistedSnapshots.get(0), initialTerm, 2, currentTerm, 3);
 191         List<ReplicatedLogEntry> unAppliedEntry = persistedSnapshots.get(0).getUnAppliedEntries();
 192         assertEquals("Persisted Snapshot getUnAppliedEntries size", 1, unAppliedEntry.size());
 193         verifyReplicatedLogEntry(unAppliedEntry.get(0), currentTerm, 3, payload3);
 194
 195         // The leader's persisted journal log should be cleared since we snapshotted.
 196         List<ReplicatedLogImplEntry> persistedLeaderJournal = InMemoryJournal.get(leaderId, ReplicatedLogImplEntry.class);
 197         assertEquals("Persisted journal log size", 0, persistedLeaderJournal.size());
 198
 199         // Allow AppendEntries to both followers to proceed. This should catch up the followers and cause a
 200         // "fake" snapshot in the leader to advance the snapshot index to 2. Also the state should be applied
 201         // in all members (via ApplyState).
 202         follower1Actor.underlyingActor().stopDropMessages(AppendEntries.class);
 203         follower2Actor.underlyingActor().stopDropMessages(AppendEntries.class);
 204
 205         ApplyState applyState = MessageCollectorActor.expectFirstMatching(leaderCollectorActor, ApplyState.class);
 206         verifyApplyState(applyState, leaderCollectorActor, payload3.toString(), currentTerm, 3, payload3);
 207
 208         verifyApplyJournalEntries(leaderCollectorActor, 3);
 209
 210         assertEquals("Leader commit index", 3, leaderContext.getCommitIndex());
 211
 212         applyState = MessageCollectorActor.expectFirstMatching(follower1CollectorActor, ApplyState.class);
 213         verifyApplyState(applyState, null, null, currentTerm, 3, payload3);
 214
 215         verifyApplyJournalEntries(follower1CollectorActor, 3);
 216
 217         applyState = MessageCollectorActor.expectFirstMatching(follower2CollectorActor, ApplyState.class);
 218         verifyApplyState(applyState, null, null, currentTerm, 3, payload3);
 219
 220         verifyApplyJournalEntries(follower2CollectorActor, 3);
 221
 222         assertEquals("Leader snapshot term", initialTerm, leaderContext.getReplicatedLog().getSnapshotTerm());
 223         assertEquals("Leader snapshot index", 2, leaderContext.getReplicatedLog().getSnapshotIndex());
 224         assertEquals("Leader journal log size", 1, leaderContext.getReplicatedLog().size());
 225         assertEquals("Leader commit index", 3, leaderContext.getCommitIndex());
 226         assertEquals("Leader last applied", 3, leaderContext.getLastApplied());
 227         assertEquals("Leader replicatedToAllIndex", 2, leader.getReplicatedToAllIndex());
 228
 229         MessageCollectorActor.clearMessages(leaderCollectorActor);
 230         MessageCollectorActor.clearMessages(follower1CollectorActor);
 231         MessageCollectorActor.clearMessages(follower2CollectorActor);
 232
 233         testLog.info("testFirstSnapshot ending");
 234     }
 235
 236     /**
 237      * Send 3 more payload instances and verify they get applied by all members.
 238      */
 239     private void testSubsequentReplications() {
 240         testLog.info("testSubsequentReplications starting");
 241
 242         payload4 = sendPayloadData(leaderActor, "four");
 243         payload5 = sendPayloadData(leaderActor, "five");
 244         payload6 = sendPayloadData(leaderActor, "six");
 245
 246         // Verify the leader applies the states.
 247         List<ApplyState> applyStates = MessageCollectorActor.expectMatching(leaderCollectorActor, ApplyState.class, 3);
 248         verifyApplyState(applyStates.get(0), leaderCollectorActor, payload4.toString(), currentTerm, 4, payload4);
 249         verifyApplyState(applyStates.get(1), leaderCollectorActor, payload5.toString(), currentTerm, 5, payload5);
 250         verifyApplyState(applyStates.get(2), leaderCollectorActor, payload6.toString(), currentTerm, 6, payload6);
 251
 252         // Verify the leader applies a log entry for at least the last entry index.
 253         verifyApplyJournalEntries(leaderCollectorActor, 6);
 254
 255         // The leader should have performed fake snapshots due to the follower's AppendEntriesReplies and
 256         // trimmed the in-memory log so that only the last entry remains.
 257         assertEquals("Leader snapshot term", currentTerm, leaderContext.getReplicatedLog().getSnapshotTerm());
 258         assertEquals("Leader snapshot index", 5, leaderContext.getReplicatedLog().getSnapshotIndex());
 259         assertEquals("Leader journal log size", 1, leaderContext.getReplicatedLog().size());
 260         assertEquals("Leader journal last index", 6, leaderContext.getReplicatedLog().lastIndex());
 261         assertEquals("Leader commit index", 6, leaderContext.getCommitIndex());
 262         assertEquals("Leader last applied", 6, leaderContext.getLastApplied());
 263         assertEquals("Leader replicatedToAllIndex", 5, leader.getReplicatedToAllIndex());
 264
 265         // Verify follower 1 applies the states.
 266         applyStates = MessageCollectorActor.expectMatching(follower1CollectorActor, ApplyState.class, 3);
 267         verifyApplyState(applyStates.get(0), null, null, currentTerm, 4, payload4);
 268         verifyApplyState(applyStates.get(1), null, null, currentTerm, 5, payload5);
 269         verifyApplyState(applyStates.get(2), null, null, currentTerm, 6, payload6);
 270
 271         // Verify follower 1 applies a log entry for at least the last entry index.
 272         verifyApplyJournalEntries(follower1CollectorActor, 6);
 273
 274         // Verify follower 2 applies the states.
 275         applyStates = MessageCollectorActor.expectMatching(follower2CollectorActor, ApplyState.class, 3);
 276         verifyApplyState(applyStates.get(0), null, null, currentTerm, 4, payload4);
 277         verifyApplyState(applyStates.get(1), null, null, currentTerm, 5, payload5);
 278         verifyApplyState(applyStates.get(2), null, null, currentTerm, 6, payload6);
 279
 280         // Verify follower 2 applies a log entry for at least the last entry index.
 281         verifyApplyJournalEntries(follower2CollectorActor, 6);
 282
 283         MessageCollectorActor.clearMessages(leaderCollectorActor);
 284
 285         testLog.info("testSubsequentReplications ending");
 286     }
 287
 288     /**
 289      * Send one more payload to trigger another snapshot. In this scenario, we delay the snapshot until
 290      * consensus occurs and the leader applies the state.
 291      * @throws Exception
 292      */
 293     private void testSecondSnapshot() throws Exception {
 294         testLog.info("testSecondSnapshot starting");
 295
 296         expSnapshotState.add(payload3);
 297         expSnapshotState.add(payload4);
 298         expSnapshotState.add(payload5);
 299         expSnapshotState.add(payload6);
 300
 301         // Delay the CaptureSnapshot message to the leader actor.
 302         leaderActor.underlyingActor().startDropMessages(CaptureSnapshotReply.class);
 303
 304         // Send the payload.
 305         payload7 = sendPayloadData(leaderActor, "seven");
 306
 307         // Capture the CaptureSnapshotReply message so we can send it later.
 308         CaptureSnapshotReply captureSnapshotReply = MessageCollectorActor.expectFirstMatching(leaderCollectorActor,
 309                 CaptureSnapshotReply.class);
 310
 311         // Wait for the state to be applied in the leader.
 312         ApplyState applyState = MessageCollectorActor.expectFirstMatching(leaderCollectorActor, ApplyState.class);
 313         verifyApplyState(applyState, leaderCollectorActor, payload7.toString(), currentTerm, 7, payload7);
 314
 315         // At this point the leader has applied the new state but the cached snapshot index should not be
 316         // advanced by a "fake" snapshot because we're in the middle of a snapshot. We'll wait for at least
 317         // one more heartbeat AppendEntriesReply to ensure this does not occur.
 318         MessageCollectorActor.clearMessages(leaderCollectorActor);
 319         MessageCollectorActor.expectFirstMatching(leaderCollectorActor, AppendEntriesReply.class);
 320
 321         assertEquals("Leader snapshot term", currentTerm, leaderContext.getReplicatedLog().getSnapshotTerm());
 322         assertEquals("Leader snapshot index", 5, leaderContext.getReplicatedLog().getSnapshotIndex());
 323         assertEquals("Leader journal log size", 2, leaderContext.getReplicatedLog().size());
 324         assertEquals("Leader journal last index", 7, leaderContext.getReplicatedLog().lastIndex());
 325         assertEquals("Leader commit index", 7, leaderContext.getCommitIndex());
 326         assertEquals("Leader last applied", 7, leaderContext.getLastApplied());
 327         assertEquals("Leader replicatedToAllIndex", 5, leader.getReplicatedToAllIndex());
 328
 329         // Now deliver the CaptureSnapshotReply.
 330         leaderActor.underlyingActor().stopDropMessages(CaptureSnapshotReply.class);
 331         leaderActor.tell(captureSnapshotReply, leaderActor);
 332
 333         // Wait for snapshot complete.
 334         MessageCollectorActor.expectFirstMatching(leaderCollectorActor, SaveSnapshotSuccess.class);
 335
 336         // Wait for another heartbeat AppendEntriesReply. This should cause a "fake" snapshot to advance the
 337         // snapshot index and trimmed the log since we're no longer in a snapshot.
 338         MessageCollectorActor.clearMessages(leaderCollectorActor);
 339         MessageCollectorActor.expectFirstMatching(leaderCollectorActor, AppendEntriesReply.class);
 340         assertEquals("Leader snapshot term", currentTerm, leaderContext.getReplicatedLog().getSnapshotTerm());
 341         assertEquals("Leader snapshot index", 6, leaderContext.getReplicatedLog().getSnapshotIndex());
 342         assertEquals("Leader journal log size", 1, leaderContext.getReplicatedLog().size());
 343         assertEquals("Leader journal last index", 7, leaderContext.getReplicatedLog().lastIndex());
 344         assertEquals("Leader commit index", 7, leaderContext.getCommitIndex());
 345
 346         // Verify the persisted snapshot. This should reflect the snapshot index as the last applied
 347         // log entry (7) and shouldn't contain any unapplied entries as we capture persisted the snapshot data
 348         // when the snapshot is created (ie when the CaptureSnapshot is processed).
 349         List<Snapshot> persistedSnapshots = InMemorySnapshotStore.getSnapshots(leaderId, Snapshot.class);
 350         assertEquals("Persisted snapshots size", 1, persistedSnapshots.size());
 351         verifySnapshot("Persisted", persistedSnapshots.get(0), currentTerm, 6, currentTerm, 7);
 352         List<ReplicatedLogEntry> unAppliedEntry = persistedSnapshots.get(0).getUnAppliedEntries();
 353         assertEquals("Persisted Snapshot getUnAppliedEntries size", 1, unAppliedEntry.size());
 354         verifyReplicatedLogEntry(unAppliedEntry.get(0), currentTerm, 7, payload7);
 355
 356         // The leader's persisted journal log should be cleared since we did a snapshot.
 357         List<ReplicatedLogImplEntry> persistedLeaderJournal = InMemoryJournal.get(
 358                 leaderId, ReplicatedLogImplEntry.class);
 359         assertEquals("Persisted journal log size", 0, persistedLeaderJournal.size());
 360
 361         // Verify the followers apply all 4 new log entries.
 362         List<ApplyState> applyStates = MessageCollectorActor.expectMatching(follower1CollectorActor, ApplyState.class, 4);
 363         verifyApplyState(applyStates.get(0), null, null, currentTerm, 4, payload4);
 364         verifyApplyState(applyStates.get(1), null, null, currentTerm, 5, payload5);
 365         verifyApplyState(applyStates.get(2), null, null, currentTerm, 6, payload6);
 366         verifyApplyState(applyStates.get(3), null, null, currentTerm, 7, payload7);
 367
 368         applyStates = MessageCollectorActor.expectMatching(follower2CollectorActor, ApplyState.class, 4);
 369         verifyApplyState(applyStates.get(0), null, null, currentTerm, 4, payload4);
 370         verifyApplyState(applyStates.get(1), null, null, currentTerm, 5, payload5);
 371         verifyApplyState(applyStates.get(2), null, null, currentTerm, 6, payload6);
 372         verifyApplyState(applyStates.get(3), null, null, currentTerm, 7, payload7);
 373
 374         // Verify the follower's snapshot index has also advanced. (after another AppendEntries heartbeat
 375         // to be safe).
 376
 377         MessageCollectorActor.clearMessages(follower1CollectorActor);
 378         MessageCollectorActor.expectFirstMatching(follower1CollectorActor, AppendEntries.class);
 379         RaftActorContext follower1Context = follower1Actor.underlyingActor().getRaftActorContext();
 380         assertEquals("Follower 1 snapshot term", currentTerm, follower1Context.getReplicatedLog().getSnapshotTerm());
 381         assertEquals("Follower 1 snapshot index", 6, follower1Context.getReplicatedLog().getSnapshotIndex());
 382         assertEquals("Follower 1 journal log size", 1, follower1Context.getReplicatedLog().size());
 383         assertEquals("Follower 1 journal last index", 7, follower1Context.getReplicatedLog().lastIndex());
 384         assertEquals("Follower 1 commit index", 7, follower1Context.getCommitIndex());
 385
 386         MessageCollectorActor.clearMessages(follower2CollectorActor);
 387         MessageCollectorActor.expectFirstMatching(follower2CollectorActor, AppendEntries.class);
 388         RaftActorContext follower2Context = follower2Actor.underlyingActor().getRaftActorContext();
 389         assertEquals("Follower 2 snapshot term", currentTerm, follower2Context.getReplicatedLog().getSnapshotTerm());
 390         assertEquals("Follower 2 snapshot index", 6, follower2Context.getReplicatedLog().getSnapshotIndex());
 391         assertEquals("Follower 2 journal log size", 1, follower2Context.getReplicatedLog().size());
 392         assertEquals("Follower 2 journal last index", 7, follower2Context.getReplicatedLog().lastIndex());
 393         assertEquals("Follower 2 commit index", 7, follower2Context.getCommitIndex());
 394
 395         expSnapshotState.add(payload7);
 396
 397         testLog.info("testSecondSnapshot ending");
 398     }
 399
 400     /**
 401      * Kill the leader actor, reinstate it and verify the recovered journal.
 402      */
 403     private void testLeaderReinstatement() {
 404         testLog.info("testLeaderReinstatement starting");
 405
 406         killActor(leaderActor);
 407
 408         leaderActor = newTestRaftActor(leaderId, peerAddresses, leaderConfigParams);
 409
 410         leaderActor.underlyingActor().waitForRecoveryComplete();
 411
 412         leaderContext = leaderActor.underlyingActor().getRaftActorContext();
 413
 414         assertEquals("Leader snapshot term", currentTerm, leaderContext.getReplicatedLog().getSnapshotTerm());
 415         assertEquals("Leader snapshot index", 6, leaderContext.getReplicatedLog().getSnapshotIndex());
 416         assertEquals("Leader journal log size", 1, leaderContext.getReplicatedLog().size());
 417         assertEquals("Leader journal last index", 7, leaderContext.getReplicatedLog().lastIndex());
 418         assertEquals("Leader commit index", 7, leaderContext.getCommitIndex());
 419         assertEquals("Leader last applied", 7, leaderContext.getLastApplied());
 420         verifyReplicatedLogEntry(leaderContext.getReplicatedLog().last(), currentTerm, 7, payload7);
 421
 422         testLog.info("testLeaderReinstatement ending");
 423     }
 424 }