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/* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.zookeeper.server.quorum;
import static org.junit.jupiter.api.Assertions.fail;
import java.io.File;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.util.HashMap;
import java.util.Map;
import org.apache.zookeeper.PortAssignment;
import org.apache.zookeeper.ZKTestCase;
import org.apache.zookeeper.server.quorum.QuorumPeer.QuorumServer;
import org.apache.zookeeper.server.quorum.QuorumPeer.ServerState;
import org.apache.zookeeper.test.ClientBase;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class FLEBackwardElectionRoundTest extends ZKTestCase {
protected static final Logger LOG = LoggerFactory.getLogger(FLELostMessageTest.class);
int count;
Map<Long, QuorumServer> peers;
File[] tmpdir;
int[] port;
QuorumCnxManager[] cnxManagers;
@BeforeEach
public void setUp() throws Exception {
count = 3;
peers = new HashMap<>(count);
tmpdir = new File[count];
port = new int[count];
cnxManagers = new QuorumCnxManager[count - 1];
}
@AfterEach
public void tearDown() throws Exception {
for (int i = 0; i < (count - 1); i++) {
if (cnxManagers[i] != null) {
cnxManagers[i].halt();
}
}
}
/**
* This test is checking the following case. A server S is
* currently LOOKING and it receives notifications from
* a quorum indicating they are following S. The election
* round E of S is higher than the election round E' in the
* notification messages, so S becomes the leader and sets
* its epoch back to E'. In the meanwhile, one or more
* followers turn to LOOKING and elect S in election round E.
* Having leader and followers with different election rounds
* might prevent other servers from electing a leader because
* they can't get a consistent set of notifications from a
* quorum.
*
* https://issues.apache.org/jira/browse/ZOOKEEPER-1514
*
*
* @throws Exception
*/
@Test
public void testBackwardElectionRound() throws Exception {
LOG.info("TestLE: {}, {}", getTestName(), count);
for (int i = 0; i < count; i++) {
int clientport = PortAssignment.unique();
peers.put(Long.valueOf(i), new QuorumServer(i, new InetSocketAddress(clientport), new InetSocketAddress(PortAssignment.unique())));
tmpdir[i] = ClientBase.createTmpDir();
port[i] = clientport;
}
ByteBuffer initialMsg0 = getMsg();
ByteBuffer initialMsg1 = getMsg();
/*
* Start server 0
*/
QuorumPeer peer = new QuorumPeer(peers, tmpdir[0], tmpdir[0], port[0], 3, 0, 1000, 2, 2, 2);
peer.startLeaderElection();
FLETestUtils.LEThread thread = new FLETestUtils.LEThread(peer, 0);
thread.start();
/*
* Start mock server 1
*/
QuorumPeer mockPeer = new QuorumPeer(peers, tmpdir[1], tmpdir[1], port[1], 3, 1, 1000, 2, 2, 2);
cnxManagers[0] = mockPeer.createCnxnManager();
cnxManagers[0].listener.start();
cnxManagers[0].toSend(0L, initialMsg0);
/*
* Start mock server 2
*/
mockPeer = new QuorumPeer(peers, tmpdir[2], tmpdir[2], port[2], 3, 2, 1000, 2, 2, 2);
cnxManagers[1] = mockPeer.createCnxnManager();
cnxManagers[1].listener.start();
cnxManagers[1].toSend(0L, initialMsg1);
/*
* Run another instance of leader election.
*/
thread.join(5000);
thread = new FLETestUtils.LEThread(peer, 0);
thread.start();
/*
* Send the same messages, this time should not make 0 the leader.
*/
cnxManagers[0].toSend(0L, initialMsg0);
cnxManagers[1].toSend(0L, initialMsg1);
thread.join(5000);
if (!thread.isAlive()) {
fail("Should not have joined");
}
}
private ByteBuffer getMsg() {
return FLETestUtils.createMsg(ServerState.FOLLOWING.ordinal(), 0, 0, 1);
}
}
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