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ASF GitHub Bot commented on ZOOKEEPER-2959: ------------------------------------------- Github user eribeiro commented on a diff in the pull request: https://github.com/apache/zookeeper/pull/500#discussion_r181564082 --- Diff: src/java/test/org/apache/zookeeper/server/quorum/ZabUtils.java --- @@ -0,0 +1,140 @@ +/** + * 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 org.apache.zookeeper.PortAssignment; +import org.apache.zookeeper.server.ServerCnxn; +import org.apache.zookeeper.server.ServerCnxnFactory; +import org.apache.zookeeper.server.ZKDatabase; +import org.apache.zookeeper.server.ZooKeeperServer; +import org.apache.zookeeper.server.persistence.FileTxnSnapLog; +import org.apache.zookeeper.server.quorum.flexible.QuorumMaj; + +import java.io.File; +import java.io.FileOutputStream; +import java.io.IOException; +import java.lang.reflect.Field; +import java.net.InetSocketAddress; +import java.util.HashMap; + +public class ZabUtils { + public static final int SYNC_LIMIT = 2; + + public static QuorumPeer createQuorumPeer(File tmpDir) throws IOException{ + QuorumPeer peer = new QuorumPeer(); + peer.syncLimit = 2; + peer.initLimit = 2; + peer.tickTime = 2000; + peer.quorumPeers = new HashMap<Long, QuorumPeer.QuorumServer>(); + peer.quorumPeers.put(0L, new QuorumPeer.QuorumServer(0, "127.0.0.1", PortAssignment.unique(), 0, null)); + peer.quorumPeers.put(1L, new QuorumPeer.QuorumServer(1, "127.0.0.1", PortAssignment.unique(), 0, null)); + peer.quorumPeers.put(2L, new QuorumPeer.QuorumServer(2, "127.0.0.1", PortAssignment.unique(), 0, null)); + peer.setQuorumVerifier(new QuorumMaj(peer.quorumPeers.size())); + peer.setCnxnFactory(new NullServerCnxnFactory()); + File version2 = new File(tmpDir, "version-2"); + version2.mkdir(); + FileOutputStream fos; + fos = new FileOutputStream(new File(version2, "currentEpoch")); + fos.write("0\n".getBytes()); + fos.close(); + fos = new FileOutputStream(new File(version2, "acceptedEpoch")); + fos.write("0\n".getBytes()); + fos.close(); + return peer; + } + + public static Leader createLeader(File tmpDir, QuorumPeer peer) + throws IOException, NoSuchFieldException, IllegalAccessException{ + LeaderZooKeeperServer zk = prepareLeader(tmpDir, peer); + return new Leader(peer, zk); + } + + public static MockLeader createMockLeader(File tmpDir, QuorumPeer peer) + throws IOException, NoSuchFieldException, IllegalAccessException{ + LeaderZooKeeperServer zk = prepareLeader(tmpDir, peer); + return new MockLeader(peer, zk); + } + + private static LeaderZooKeeperServer prepareLeader(File tmpDir, QuorumPeer peer) + throws IOException, NoSuchFieldException, IllegalAccessException { + FileTxnSnapLog logFactory = new FileTxnSnapLog(tmpDir, tmpDir); + peer.setTxnFactory(logFactory); + Field addrField = peer.getClass().getDeclaredField("myQuorumAddr"); + addrField.setAccessible(true); + addrField.set(peer, new InetSocketAddress(PortAssignment.unique())); + ZKDatabase zkDb = new ZKDatabase(logFactory); + return new LeaderZooKeeperServer(logFactory, peer, new ZooKeeperServer.BasicDataTreeBuilder(), zkDb); + } + + private static final class NullServerCnxnFactory extends ServerCnxnFactory { + public void startup(ZooKeeperServer zkServer) throws IOException, + InterruptedException { + } + public void start() { + } + public void shutdown() { + } + public void setMaxClientCnxnsPerHost(int max) { + } + public void join() throws InterruptedException { + } + public int getMaxClientCnxnsPerHost() { + return 0; + } + public int getLocalPort() { + return 0; + } + public InetSocketAddress getLocalAddress() { + return null; + } + public Iterable<ServerCnxn> getConnections() { + return null; + } + public void configure(InetSocketAddress addr, int maxClientCnxns) + throws IOException { + } + public void closeSession(long sessionId) { + } + public void closeAll() { + } + @Override + public int getNumAliveConnections() { + return 0; + } + } + + static final class MockLeader extends Leader { --- End diff -- `private` ? > ignore accepted epoch and LEADERINFO ack from observers when a newly elected > leader computes new epoch > ------------------------------------------------------------------------------------------------------ > > Key: ZOOKEEPER-2959 > URL: https://issues.apache.org/jira/browse/ZOOKEEPER-2959 > Project: ZooKeeper > Issue Type: Bug > Affects Versions: 3.4.10, 3.5.3 > Reporter: xiangyq000 > Assignee: Bogdan Kanivets > Priority: Blocker > > Once the ZooKeeper cluster finishes the election for new leader, all learners > report their accepted epoch to the leader for the computation of new cluster > epoch. > org.apache.zookeeper.server.quorum.Leader#getEpochToPropose > {code:java} > private final HashSet<Long> connectingFollowers = new HashSet<Long>(); > public long getEpochToPropose(long sid, long lastAcceptedEpoch) throws > InterruptedException, IOException { > synchronized(connectingFollowers) { > if (!waitingForNewEpoch) { > return epoch; > } > if (lastAcceptedEpoch >= epoch) { > epoch = lastAcceptedEpoch+1; > } > connectingFollowers.add(sid); > QuorumVerifier verifier = self.getQuorumVerifier(); > if (connectingFollowers.contains(self.getId()) && > > verifier.containsQuorum(connectingFollowers)) { > waitingForNewEpoch = false; > self.setAcceptedEpoch(epoch); > connectingFollowers.notifyAll(); > } else { > long start = Time.currentElapsedTime(); > long cur = start; > long end = start + self.getInitLimit()*self.getTickTime(); > while(waitingForNewEpoch && cur < end) { > connectingFollowers.wait(end - cur); > cur = Time.currentElapsedTime(); > } > if (waitingForNewEpoch) { > throw new InterruptedException("Timeout while waiting for > epoch from quorum"); > } > } > return epoch; > } > } > {code} > The computation will get an outcome once : > # The leader has call method "getEpochToPropose" > # The number of all reporters is greater than half of participants. > The problem is, an observer server will also send its accepted epoch to the > leader, while this procedure treat observers as participants. > Supposed that the cluster consists of 1 leader, 2 followers and 1 observer, > and now the leader and the observer have reported their accepted epochs while > neither of the followers has. Thus, the connectingFollowers set consists of > two elements, resulting in a size of 2, which is greater than half quorum, > namely, 2. Then QuorumVerifier#containsQuorum will return true, because it > does not check whether the elements of the parameter are participants. > The same flaw exists in > org.apache.zookeeper.server.quorum.Leader#waitForEpochAck -- This message was sent by Atlassian JIRA (v7.6.3#76005)