opendaylight/md-sal/sal-akka-raft/src/test/java/org/opendaylight/controller/cluster/raft/behaviors/PartitionedCandidateOnStartupElectionScenarioTest.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.behaviors;
   9
  10 import static org.junit.Assert.assertEquals;
  11 import akka.actor.ActorRef;
  12 import com.google.common.collect.ImmutableMap;
  13 import org.junit.Test;
  14 import org.opendaylight.controller.cluster.raft.DefaultConfigParamsImpl;
  15 import org.opendaylight.controller.cluster.raft.MockRaftActorContext.MockPayload;
  16 import org.opendaylight.controller.cluster.raft.MockRaftActorContext.MockReplicatedLogEntry;
  17 import org.opendaylight.controller.cluster.raft.MockRaftActorContext.SimpleReplicatedLog;
  18 import org.opendaylight.controller.cluster.raft.RaftState;
  19 import org.opendaylight.controller.cluster.raft.base.messages.ElectionTimeout;
  20 import org.opendaylight.controller.cluster.raft.base.messages.TimeoutNow;
  21 import org.opendaylight.controller.cluster.raft.messages.RequestVote;
  22 import org.opendaylight.controller.cluster.raft.messages.RequestVoteReply;
  23
  24 /**
  25  * A leader election scenario test that partitions a candidate when trying to join a cluster on startup.
  26  *
  27  * @author Thomas Pantelis
  28  */
  29 public class PartitionedCandidateOnStartupElectionScenarioTest extends AbstractLeaderElectionScenarioTest {
  30
  31     private final int numCandidateElections = 5;
  32     private long candidateElectionTerm;
  33
  34     @Test
  35     public void runTest() throws Exception {
  36         testLog.info("PartitionedCandidateOnStartupElectionScenarioTest starting");
  37
  38         setupInitialMember1AndMember2Behaviors();
  39
  40         setupPartitionedCandidateMember3AndSendElectionTimeouts();
  41
  42         resolvePartitionAndSendElectionTimeoutsToCandidateMember3();
  43
  44         sendElectionTimeoutToFollowerMember1();
  45
  46         testLog.info("PartitionedCandidateOnStartupElectionScenarioTest ending");
  47     }
  48
  49     private void sendElectionTimeoutToFollowerMember1() throws Exception {
  50         testLog.info("sendElectionTimeoutToFollowerMember1 starting");
  51
  52         // At this point we have no leader. Candidate member 3 would continue to start new elections
  53         // but wouldn't be granted a vote. One of the 2 followers would eventually time out from
  54         // not having received a heartbeat from a leader and switch to candidate and start a new
  55         // election. We'll simulate that here by sending an ElectionTimeout to member 1.
  56
  57         member1Actor.clear();
  58         member1Actor.expectMessageClass(RequestVoteReply.class, 1);
  59         member2Actor.clear();
  60         member2Actor.expectMessageClass(RequestVote.class, 1);
  61         member3Actor.clear();
  62         member3Actor.expectMessageClass(RequestVote.class, 1);
  63         member3Actor.expectBehaviorStateChange();
  64
  65         member1ActorRef.tell(TimeoutNow.INSTANCE, ActorRef.noSender());
  66
  67         member2Actor.waitForExpectedMessages(RequestVote.class);
  68         member3Actor.waitForExpectedMessages(RequestVote.class);
  69
  70         // The RequestVoteReply should come from Follower member 2 and the vote should be granted
  71         // since member 2's last term and index matches member 1's.
  72
  73         member1Actor.waitForExpectedMessages(RequestVoteReply.class);
  74
  75         RequestVoteReply requestVoteReply = member1Actor.getCapturedMessage(RequestVoteReply.class);
  76         assertEquals("getTerm", member1Context.getTermInformation().getCurrentTerm(), requestVoteReply.getTerm());
  77         assertEquals("isVoteGranted", true, requestVoteReply.isVoteGranted());
  78
  79         // Candidate member 3 should change to follower as its term should be less than the
  80         // RequestVote term (member 1 started a new term higher than the other member's terms).
  81
  82         member3Actor.waitForBehaviorStateChange();
  83
  84         verifyBehaviorState("member 1", member1Actor, RaftState.Leader);
  85         verifyBehaviorState("member 2", member2Actor, RaftState.Follower);
  86         verifyBehaviorState("member 3", member3Actor, RaftState.Follower);
  87
  88         // newTerm should be 10.
  89
  90         long newTerm = candidateElectionTerm + 1;
  91         assertEquals("member 1 election term", newTerm, member1Context.getTermInformation().getCurrentTerm());
  92         assertEquals("member 2 election term", newTerm, member2Context.getTermInformation().getCurrentTerm());
  93         assertEquals("member 3 election term", newTerm, member3Context.getTermInformation().getCurrentTerm());
  94
  95         testLog.info("sendElectionTimeoutToFollowerMember1 ending");
  96     }
  97
  98     private void resolvePartitionAndSendElectionTimeoutsToCandidateMember3() throws Exception {
  99         testLog.info("resolvePartitionAndSendElectionTimeoutsToCandidateMember3 starting");
 100
 101         // Now send a couple more ElectionTimeouts to Candidate member 3 with the partition resolved.
 102         //
 103         // On the first RequestVote, Leader member 1 should switch to Follower as its term (s) is less than
 104         // the RequestVote's term (8) from member 3. No RequestVoteReply should be sent by member 1.
 105         // Follower member 2 should update its term since it less than the RequestVote's term and
 106         // should return a RequestVoteReply but should not grant the vote as its last term and index
 107         // is greater than the RequestVote's lastLogTerm and lastLogIndex, ie member 2's log is later
 108         // or more up to date than member 3's.
 109         //
 110         // On the second RequestVote, both member 1 and 2 are followers so they should update their
 111         // term and return a RequestVoteReply but should not grant the vote.
 112
 113         candidateElectionTerm += 2;
 114         for(int i = 0; i < 2; i++) {
 115             member1Actor.clear();
 116             member1Actor.expectMessageClass(RequestVote.class, 1);
 117             member2Actor.clear();
 118             member2Actor.expectMessageClass(RequestVote.class, 1);
 119             member3Actor.clear();
 120             member3Actor.expectMessageClass(RequestVoteReply.class, 1);
 121
 122             member3ActorRef.tell(ElectionTimeout.INSTANCE, ActorRef.noSender());
 123
 124             member1Actor.waitForExpectedMessages(RequestVote.class);
 125             member2Actor.waitForExpectedMessages(RequestVote.class);
 126
 127             member3Actor.waitForExpectedMessages(RequestVoteReply.class);
 128
 129             RequestVoteReply requestVoteReply = member3Actor.getCapturedMessage(RequestVoteReply.class);
 130             assertEquals("getTerm", member3Context.getTermInformation().getCurrentTerm(), requestVoteReply.getTerm());
 131             assertEquals("isVoteGranted", false, requestVoteReply.isVoteGranted());
 132         }
 133
 134         verifyBehaviorState("member 1", member1Actor, RaftState.Follower);
 135         verifyBehaviorState("member 2", member2Actor, RaftState.Follower);
 136         verifyBehaviorState("member 3", member3Actor, RaftState.Candidate);
 137
 138         // Even though member 3 didn't get voted for, member 1 and 2 should have updated their term
 139         // to member 3's.
 140
 141         assertEquals("member 1 election term", candidateElectionTerm,
 142                 member1Context.getTermInformation().getCurrentTerm());
 143         assertEquals("member 2 election term", candidateElectionTerm,
 144                 member2Context.getTermInformation().getCurrentTerm());
 145         assertEquals("member 3 election term", candidateElectionTerm,
 146                 member3Context.getTermInformation().getCurrentTerm());
 147
 148         testLog.info("resolvePartitionAndSendElectionTimeoutsToCandidateMember3 ending");
 149     }
 150
 151     private void setupPartitionedCandidateMember3AndSendElectionTimeouts() {
 152         testLog.info("setupPartitionedCandidateMember3AndSendElectionTimeouts starting");
 153
 154         // Create member 3's behavior initially as a Candidate.
 155
 156         member3Context = newRaftActorContext("member3", member3ActorRef,
 157                 ImmutableMap.<String,String>builder().
 158                     put("member1", member1ActorRef.path().toString()).
 159                     put("member2", member2ActorRef.path().toString()).build());
 160
 161         DefaultConfigParamsImpl member3ConfigParams = newConfigParams();
 162         member3Context.setConfigParams(member3ConfigParams);
 163
 164         // Initialize the ReplicatedLog and election term info for Candidate member 3. The current term
 165         // will be 2 and the last term will be 1 so it is behind the leader's log.
 166
 167         SimpleReplicatedLog candidateReplicatedLog = new SimpleReplicatedLog();
 168         candidateReplicatedLog.append(new MockReplicatedLogEntry(1, 1, new MockPayload("")));
 169         candidateReplicatedLog.append(new MockReplicatedLogEntry(2, 1, new MockPayload("")));
 170
 171         member3Context.setReplicatedLog(candidateReplicatedLog);
 172         member3Context.getTermInformation().update(2, member1Context.getId());
 173
 174         // The member 3 Candidate will start a new term and send RequestVotes. However it will be
 175         // partitioned from the cluster by having member 1 and 2 drop its RequestVote messages.
 176
 177         candidateElectionTerm = member3Context.getTermInformation().getCurrentTerm() + numCandidateElections;
 178
 179         member1Actor.dropMessagesToBehavior(RequestVote.class, numCandidateElections);
 180
 181         member2Actor.dropMessagesToBehavior(RequestVote.class, numCandidateElections);
 182
 183         Candidate member3Behavior = new Candidate(member3Context);
 184         member3Actor.behavior = member3Behavior;
 185         member3Context.setCurrentBehavior(member3Behavior);
 186
 187         // Send several additional ElectionTimeouts to Candidate member 3. Each ElectionTimeout will
 188         // start a new term so Candidate member 3's current term will be greater than the leader's
 189         // current term.
 190
 191         for(int i = 0; i < numCandidateElections - 1; i++) {
 192             member3ActorRef.tell(ElectionTimeout.INSTANCE, ActorRef.noSender());
 193         }
 194
 195         member1Actor.waitForExpectedMessages(RequestVote.class);
 196         member2Actor.waitForExpectedMessages(RequestVote.class);
 197
 198         verifyBehaviorState("member 1", member1Actor, RaftState.Leader);
 199         verifyBehaviorState("member 2", member2Actor, RaftState.Follower);
 200         verifyBehaviorState("member 3", member3Actor, RaftState.Candidate);
 201
 202         assertEquals("member 1 election term", 3, member1Context.getTermInformation().getCurrentTerm());
 203         assertEquals("member 2 election term", 3, member2Context.getTermInformation().getCurrentTerm());
 204         assertEquals("member 3 election term", candidateElectionTerm,
 205                 member3Context.getTermInformation().getCurrentTerm());
 206
 207         testLog.info("setupPartitionedCandidateMember3AndSendElectionTimeouts ending");
 208     }
 209
 210     private void setupInitialMember1AndMember2Behaviors() throws Exception {
 211         testLog.info("setupInitialMember1AndMember2Behaviors starting");
 212
 213         // Create member 2's behavior as Follower.
 214
 215         member2Context = newRaftActorContext("member2", member2ActorRef,
 216                 ImmutableMap.<String,String>builder().
 217                     put("member1", member1ActorRef.path().toString()).
 218                     put("member3", member3ActorRef.path().toString()).build());
 219
 220         DefaultConfigParamsImpl member2ConfigParams = newConfigParams();
 221         member2Context.setConfigParams(member2ConfigParams);
 222
 223         member2Actor.behavior = new Follower(member2Context);
 224         member2Context.setCurrentBehavior(member2Actor.behavior);
 225
 226         // Create member 1's behavior as Leader.
 227
 228         member1Context = newRaftActorContext("member1", member1ActorRef,
 229                 ImmutableMap.<String,String>builder().
 230                     put("member2", member2ActorRef.path().toString()).
 231                     put("member3", member3ActorRef.path().toString()).build());
 232
 233         DefaultConfigParamsImpl member1ConfigParams = newConfigParams();
 234         member1Context.setConfigParams(member1ConfigParams);
 235
 236         initializeLeaderBehavior(member1Actor, member1Context, 1);
 237
 238         member2Actor.clear();
 239         member3Actor.clear();
 240
 241         // Initialize the ReplicatedLog and election term info for member 1 and 2. The current term
 242         // will be 3 and the last term will be 2.
 243
 244         SimpleReplicatedLog replicatedLog = new SimpleReplicatedLog();
 245         replicatedLog.append(new MockReplicatedLogEntry(2, 1, new MockPayload("")));
 246         replicatedLog.append(new MockReplicatedLogEntry(3, 1, new MockPayload("")));
 247
 248         member1Context.setReplicatedLog(replicatedLog);
 249         member1Context.getTermInformation().update(3, "");
 250
 251         member2Context.setReplicatedLog(replicatedLog);
 252         member2Context.getTermInformation().update(3, member1Context.getId());
 253
 254         testLog.info("setupInitialMember1AndMember2Behaviors ending");
 255
 256     }
 257 }