[GitHub] [kafka] soarez commented on a diff in pull request #13558: KAFKA-14845: Fix broker registration with Zookeeper when the previous ephemeral znode was not properly recorded by the broker

["soarez (via GitHub)" <gi...@apache.org>]

soarez commented on code in PR #13558:
URL: https://github.com/apache/kafka/pull/13558#discussion_r1197495849


##########
core/src/test/resources/log4j.properties:
##########
@@ -20,7 +20,8 @@ log4j.appender.stdout.layout.ConversionPattern=[%d] %p %m (%c:%L)%n
 
 log4j.logger.kafka=WARN
 log4j.logger.org.apache.kafka=WARN
-
+log4j.logger.kafka.zk=INFO
+log4j.logger.org.apache.zookeeper.server=INFO

Review Comment:
   Do we really want to enable this for all tests? Should we instead leave a comment on the new test that suggests enabling these for troubleshooting as needed?



##########
core/src/test/java/kafka/zk/ZkBrokerRegistrationTest.java:
##########
@@ -0,0 +1,298 @@
+/*
+ * 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 kafka.zk;
+
+import io.netty.channel.group.ChannelGroup;
+import io.netty.util.concurrent.EventExecutor;
+import kafka.cluster.Broker;
+import kafka.server.KafkaConfig;
+import kafka.zookeeper.ZooKeeperClient;
+import org.apache.kafka.common.network.ListenerName;
+import org.apache.kafka.common.utils.Time;
+import org.apache.zookeeper.ZooDefs;
+import org.apache.zookeeper.client.ZKClientConfig;
+import org.apache.zookeeper.server.PrepRequestProcessor;
+import org.apache.zookeeper.server.RequestProcessor;
+import org.apache.zookeeper.server.ServerCnxnFactory;
+import org.apache.zookeeper.server.SyncRequestProcessor;
+import org.apache.zookeeper.server.ZooKeeperServer;
+import org.apache.zookeeper.server.persistence.FileTxnSnapLog;
+import org.apache.zookeeper.server.quorum.QuorumPeerConfig;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.lang.reflect.Field;
+import java.net.ServerSocket;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Properties;
+import java.util.concurrent.CountDownLatch;
+
+import static java.util.Arrays.asList;
+import static org.apache.kafka.common.security.auth.SecurityProtocol.PLAINTEXT;
+import static org.apache.zookeeper.client.ZKClientConfig.ZOOKEEPER_CLIENT_CNXN_SOCKET;
+
+/**
+ * This test simulates the loss of a session ID with Zookeeper (for instance due to network partition)
+ * while a broker is in the process of creating its ephemeral znode under /brokers/ids/. This can
+ * result in broker registration failing with due to a NODEEXISTS error which is not handled by the
+ * fix KAFKA-6584 because in this case, the ID of the session of the conflicting ephemeral znode is
+ * not known by the broker. See KAFKA-14845 for an example of timeline of events requires to reproduce
+ * the use case.
+ */
+public class ZkBrokerRegistrationTest {
+    private static final Logger log = LoggerFactory.getLogger(ZkBrokerRegistrationTest.class);
+
+    private KafkaConfig kafkaConfig;
+    private BrokerInfo brokerInfo;
+    private int zkPort;
+
+    private class SandboxedZookeeper extends Thread {
+        private final CountDownLatch zookeeperStopLatch;
+        private final CountDownLatch zookeeperStartLatch = new CountDownLatch(1);
+        private final ZkTestContext spec;
+        private InstrumentedRequestProcessor processor;
+
+        SandboxedZookeeper(CountDownLatch zookeeperStopLatch, ZkTestContext spec) {
+            this.zookeeperStopLatch = zookeeperStopLatch;
+            this.spec = spec;
+        }
+
+        public void run() {
+            ServerCnxnFactory cnxnFactory = null;
+
+            try {
+                Path dataDir = Files.createTempDirectory("zk");
+
+                Properties zkProperties = new Properties();
+                zkProperties.put("dataDir", dataDir.toFile().getPath());
+                zkProperties.put("clientPort", String.valueOf(zkPort));
+                zkProperties.put("serverCnxnFactory", "org.apache.zookeeper.server.NettyServerCnxnFactory");
+
+                QuorumPeerConfig config = new QuorumPeerConfig();
+                config.parseProperties(zkProperties);
+                FileTxnSnapLog txnLog = new FileTxnSnapLog(config.getDataLogDir(), config.getDataDir());
+
+                ZooKeeperServer zookeeper = new InstrumentedZooKeeperServer(
+                    null,
+                    txnLog,
+                    config.getTickTime(),
+                    config.getMinSessionTimeout(),
+                    config.getMaxSessionTimeout(),
+                    config.getClientPortListenBacklog(),
+                    null,
+                    config.getInitialConfig(),
+                    spec) {
+
+                    @Override
+                    protected void setupRequestProcessors() {
+                        processor = new InstrumentedRequestProcessor(this, spec);
+                        RequestProcessor syncProcessor = new SyncRequestProcessor(this, processor);
+                        ((SyncRequestProcessor) syncProcessor).start();
+                        firstProcessor = new PrepRequestProcessor(this, syncProcessor);
+                        ((PrepRequestProcessor) firstProcessor).start();
+                    }
+                };
+
+                cnxnFactory = ServerCnxnFactory.createFactory();
+                cnxnFactory.configure(
+                    config.getClientPortAddress(),
+                    config.getMaxClientCnxns(),
+                    config.getClientPortListenBacklog(),
+                    false);
+                cnxnFactory.startup(zookeeper);
+
+                zookeeperStartLatch.countDown();
+                zookeeperStopLatch.await();

Review Comment:
   It's a bit odd to keep an extra thread just waiting for a signal to shut down ZK. Could we not have `start()` and `stop()` methods instead?



##########
core/src/test/java/kafka/zk/ReceiptEvent.java:
##########
@@ -0,0 +1,100 @@
+/*
+ * 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 kafka.zk;
+
+import org.apache.zookeeper.server.MutedServerCxn;
+import org.apache.zookeeper.server.Request;
+import org.apache.zookeeper.server.ServerCnxn;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.concurrent.locks.Condition;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
+
+/**
+ * Event corresponding to the invocation of the Zookeeper request processor for a request.
+ */
+public class ReceiptEvent {
+    private final int opCode;
+    private final Lock lock = new ReentrantLock();
+    private final Condition received = lock.newCondition();
+    private final Condition processed = lock.newCondition();
+    private State state = State.notReceived;
+    private boolean sendResponse;
+
+    public ReceiptEvent(int opCode, boolean sendResponse) {
+        this.opCode = opCode;
+        this.sendResponse = sendResponse;
+    }
+
+    public boolean matches(Request request) {
+        return request.type == opCode;
+    }
+
+    public void serverReceived() {
+        lock.lock();
+        try {
+            state = Collections.max(Arrays.asList(state, State.received));
+            received.signalAll();

Review Comment:
   This condition doesn't seem to be used anywhere?



##########
core/src/test/java/kafka/zk/ReceiptEvent.java:
##########
@@ -0,0 +1,100 @@
+/*
+ * 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 kafka.zk;
+
+import org.apache.zookeeper.server.MutedServerCxn;
+import org.apache.zookeeper.server.Request;
+import org.apache.zookeeper.server.ServerCnxn;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.concurrent.locks.Condition;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
+
+/**
+ * Event corresponding to the invocation of the Zookeeper request processor for a request.
+ */
+public class ReceiptEvent {
+    private final int opCode;
+    private final Lock lock = new ReentrantLock();
+    private final Condition received = lock.newCondition();
+    private final Condition processed = lock.newCondition();

Review Comment:
   Could this maybe be lighter on locking by using with a `AtomicReference<State>.compareAndSet()` on `serverProcessed()` and conditionally completing a `CompletableFuture<Void> processed` for `awaitProcessed()` to `.get()` on?



##########
checkstyle/suppressions.xml:
##########
@@ -41,6 +41,8 @@
     <suppress checks="NPathComplexity" files="(ClusterTestExtensions|KafkaApisBuilder).java"/>
     <suppress checks="MethodLength"
               files="(KafkaClusterTestKit).java"/>
+    <suppress checks="ImportControl"
+              files="(ZkBrokerRegistrationTest|DelegatingRequest|InstrumentedRequestProcessor|InstrumentedZooKeeperServer|ReceiptEvent|MutedServerCxn).java"/>

Review Comment:
   Why add this exception instead of sorting the import statements as per checkstyle rules?



##########
core/src/test/java/kafka/zk/ZkBrokerRegistrationTest.java:
##########
@@ -0,0 +1,298 @@
+/*
+ * 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 kafka.zk;
+
+import io.netty.channel.group.ChannelGroup;
+import io.netty.util.concurrent.EventExecutor;
+import kafka.cluster.Broker;
+import kafka.server.KafkaConfig;
+import kafka.zookeeper.ZooKeeperClient;
+import org.apache.kafka.common.network.ListenerName;
+import org.apache.kafka.common.utils.Time;
+import org.apache.zookeeper.ZooDefs;
+import org.apache.zookeeper.client.ZKClientConfig;
+import org.apache.zookeeper.server.PrepRequestProcessor;
+import org.apache.zookeeper.server.RequestProcessor;
+import org.apache.zookeeper.server.ServerCnxnFactory;
+import org.apache.zookeeper.server.SyncRequestProcessor;
+import org.apache.zookeeper.server.ZooKeeperServer;
+import org.apache.zookeeper.server.persistence.FileTxnSnapLog;
+import org.apache.zookeeper.server.quorum.QuorumPeerConfig;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.lang.reflect.Field;
+import java.net.ServerSocket;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Properties;
+import java.util.concurrent.CountDownLatch;
+
+import static java.util.Arrays.asList;
+import static org.apache.kafka.common.security.auth.SecurityProtocol.PLAINTEXT;
+import static org.apache.zookeeper.client.ZKClientConfig.ZOOKEEPER_CLIENT_CNXN_SOCKET;
+
+/**
+ * This test simulates the loss of a session ID with Zookeeper (for instance due to network partition)
+ * while a broker is in the process of creating its ephemeral znode under /brokers/ids/. This can
+ * result in broker registration failing with due to a NODEEXISTS error which is not handled by the
+ * fix KAFKA-6584 because in this case, the ID of the session of the conflicting ephemeral znode is
+ * not known by the broker. See KAFKA-14845 for an example of timeline of events requires to reproduce
+ * the use case.
+ */
+public class ZkBrokerRegistrationTest {
+    private static final Logger log = LoggerFactory.getLogger(ZkBrokerRegistrationTest.class);
+
+    private KafkaConfig kafkaConfig;
+    private BrokerInfo brokerInfo;
+    private int zkPort;
+
+    private class SandboxedZookeeper extends Thread {
+        private final CountDownLatch zookeeperStopLatch;
+        private final CountDownLatch zookeeperStartLatch = new CountDownLatch(1);
+        private final ZkTestContext spec;
+        private InstrumentedRequestProcessor processor;

Review Comment:
   This doesn't seem to be used, can be local.



##########
core/src/main/scala/kafka/zk/KafkaZkClient.scala:
##########
@@ -2113,7 +2113,12 @@ class KafkaZkClient private[zk] (zooKeeperClient: ZooKeeperClient, isSecure: Boo
   }
 
   private class CheckedEphemeral(path: String, data: Array[Byte]) extends Logging {
+    private var attempt = 0
+    private val maxAttempt = 5
+    private val backoffMs = 1000

Review Comment:
   Should this be a function of the `"zookeeper.session.timeout.ms"` config property?



##########
core/src/test/java/kafka/zk/ZkBrokerRegistrationTest.java:
##########
@@ -0,0 +1,298 @@
+/*
+ * 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 kafka.zk;
+
+import io.netty.channel.group.ChannelGroup;
+import io.netty.util.concurrent.EventExecutor;
+import kafka.cluster.Broker;
+import kafka.server.KafkaConfig;
+import kafka.zookeeper.ZooKeeperClient;
+import org.apache.kafka.common.network.ListenerName;
+import org.apache.kafka.common.utils.Time;
+import org.apache.zookeeper.ZooDefs;
+import org.apache.zookeeper.client.ZKClientConfig;
+import org.apache.zookeeper.server.PrepRequestProcessor;
+import org.apache.zookeeper.server.RequestProcessor;
+import org.apache.zookeeper.server.ServerCnxnFactory;
+import org.apache.zookeeper.server.SyncRequestProcessor;
+import org.apache.zookeeper.server.ZooKeeperServer;
+import org.apache.zookeeper.server.persistence.FileTxnSnapLog;
+import org.apache.zookeeper.server.quorum.QuorumPeerConfig;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.lang.reflect.Field;
+import java.net.ServerSocket;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Properties;
+import java.util.concurrent.CountDownLatch;
+
+import static java.util.Arrays.asList;
+import static org.apache.kafka.common.security.auth.SecurityProtocol.PLAINTEXT;
+import static org.apache.zookeeper.client.ZKClientConfig.ZOOKEEPER_CLIENT_CNXN_SOCKET;
+
+/**
+ * This test simulates the loss of a session ID with Zookeeper (for instance due to network partition)
+ * while a broker is in the process of creating its ephemeral znode under /brokers/ids/. This can
+ * result in broker registration failing with due to a NODEEXISTS error which is not handled by the
+ * fix KAFKA-6584 because in this case, the ID of the session of the conflicting ephemeral znode is
+ * not known by the broker. See KAFKA-14845 for an example of timeline of events requires to reproduce
+ * the use case.
+ */
+public class ZkBrokerRegistrationTest {
+    private static final Logger log = LoggerFactory.getLogger(ZkBrokerRegistrationTest.class);
+
+    private KafkaConfig kafkaConfig;
+    private BrokerInfo brokerInfo;
+    private int zkPort;
+
+    private class SandboxedZookeeper extends Thread {
+        private final CountDownLatch zookeeperStopLatch;
+        private final CountDownLatch zookeeperStartLatch = new CountDownLatch(1);
+        private final ZkTestContext spec;
+        private InstrumentedRequestProcessor processor;
+
+        SandboxedZookeeper(CountDownLatch zookeeperStopLatch, ZkTestContext spec) {
+            this.zookeeperStopLatch = zookeeperStopLatch;
+            this.spec = spec;
+        }
+
+        public void run() {
+            ServerCnxnFactory cnxnFactory = null;
+
+            try {
+                Path dataDir = Files.createTempDirectory("zk");
+
+                Properties zkProperties = new Properties();
+                zkProperties.put("dataDir", dataDir.toFile().getPath());
+                zkProperties.put("clientPort", String.valueOf(zkPort));
+                zkProperties.put("serverCnxnFactory", "org.apache.zookeeper.server.NettyServerCnxnFactory");
+
+                QuorumPeerConfig config = new QuorumPeerConfig();
+                config.parseProperties(zkProperties);
+                FileTxnSnapLog txnLog = new FileTxnSnapLog(config.getDataLogDir(), config.getDataDir());
+
+                ZooKeeperServer zookeeper = new InstrumentedZooKeeperServer(
+                    null,
+                    txnLog,
+                    config.getTickTime(),
+                    config.getMinSessionTimeout(),
+                    config.getMaxSessionTimeout(),
+                    config.getClientPortListenBacklog(),
+                    null,
+                    config.getInitialConfig(),
+                    spec) {
+
+                    @Override
+                    protected void setupRequestProcessors() {
+                        processor = new InstrumentedRequestProcessor(this, spec);
+                        RequestProcessor syncProcessor = new SyncRequestProcessor(this, processor);
+                        ((SyncRequestProcessor) syncProcessor).start();
+                        firstProcessor = new PrepRequestProcessor(this, syncProcessor);
+                        ((PrepRequestProcessor) firstProcessor).start();
+                    }

Review Comment:
   Can't this be part of `InstrumentedZooKeeperServer`, since it's a new class anyway? 



##########
core/src/test/java/kafka/zk/ZkBrokerRegistrationTest.java:
##########
@@ -0,0 +1,298 @@
+/*
+ * 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 kafka.zk;
+
+import io.netty.channel.group.ChannelGroup;
+import io.netty.util.concurrent.EventExecutor;
+import kafka.cluster.Broker;
+import kafka.server.KafkaConfig;
+import kafka.zookeeper.ZooKeeperClient;
+import org.apache.kafka.common.network.ListenerName;
+import org.apache.kafka.common.utils.Time;
+import org.apache.zookeeper.ZooDefs;
+import org.apache.zookeeper.client.ZKClientConfig;
+import org.apache.zookeeper.server.PrepRequestProcessor;
+import org.apache.zookeeper.server.RequestProcessor;
+import org.apache.zookeeper.server.ServerCnxnFactory;
+import org.apache.zookeeper.server.SyncRequestProcessor;
+import org.apache.zookeeper.server.ZooKeeperServer;
+import org.apache.zookeeper.server.persistence.FileTxnSnapLog;
+import org.apache.zookeeper.server.quorum.QuorumPeerConfig;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.lang.reflect.Field;
+import java.net.ServerSocket;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Properties;
+import java.util.concurrent.CountDownLatch;
+
+import static java.util.Arrays.asList;
+import static org.apache.kafka.common.security.auth.SecurityProtocol.PLAINTEXT;
+import static org.apache.zookeeper.client.ZKClientConfig.ZOOKEEPER_CLIENT_CNXN_SOCKET;
+
+/**
+ * This test simulates the loss of a session ID with Zookeeper (for instance due to network partition)
+ * while a broker is in the process of creating its ephemeral znode under /brokers/ids/. This can
+ * result in broker registration failing with due to a NODEEXISTS error which is not handled by the
+ * fix KAFKA-6584 because in this case, the ID of the session of the conflicting ephemeral znode is
+ * not known by the broker. See KAFKA-14845 for an example of timeline of events requires to reproduce
+ * the use case.
+ */
+public class ZkBrokerRegistrationTest {

Review Comment:
   Since we're finding a free port and starting zookeeper and everything, shouldn't we tag as an integration test using `@Tag("integration")`?



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