Remove ZooKeeper

README.md

@@ -91,9 +91,9 @@ Control). The metrics reporter periodically samples the Kafka raw metrics on the
     * If the default broker cleanup policy is `compact`, make sure that the topic to which Cruise Control metrics
     reporter should send messages is created with the `delete` cleanup policy -- the default metrics reporter topic
     is `__CruiseControlMetrics`.
-2. Start ZooKeeper and Kafka server ([See tutorial](https://kafka.apache.org/quickstart)).
+2. Start Kafka server ([See tutorial](https://kafka.apache.org/quickstart)).
 3. Modify `config/cruisecontrol.properties` of Cruise Control:
-    * (Required) fill in `bootstrap.servers` and `zookeeper.connect` to the Kafka cluster to be monitored.
+    * (Required) fill in `bootstrap.servers` to the Kafka cluster to be monitored.
     * (Required) update `capacity.config.file` to the path of your capacity file.  
       * Capacity file is a JSON file that provides the capacity of the brokers
       * You can start Cruise Control server with the default file (`config/capacityJBOD.json`), but it may not reflect the actual capacity of the brokers 

build.gradle

@@ -275,7 +275,6 @@ project(':cruise-control') {
     api project(':cruise-control-core')
     implementation "org.slf4j:slf4j-api:1.7.36"
     implementation "org.apache.logging.log4j:log4j-slf4j-impl:2.17.2"
-    implementation "org.apache.zookeeper:zookeeper:${zookeeperVersion}"
     implementation "io.netty:netty-handler:${nettyVersion}"
     implementation "io.netty:netty-transport-native-epoll:${nettyVersion}"
     api "org.apache.kafka:kafka_$scalaBinaryVersion:$kafkaVersion"
@@ -461,9 +460,10 @@ project(':cruise-control-metrics-reporter') {
     testImplementation "org.apache.kafka:kafka-clients:$kafkaVersion:test"
     testImplementation "org.apache.kafka:kafka-server-common:$kafkaVersion"
     testImplementation "org.apache.kafka:kafka-group-coordinator:$kafkaVersion"
+    testImplementation "org.apache.kafka:kafka-metadata:$kafkaVersion"
+    testImplementation "org.apache.kafka:kafka-raft:$kafkaVersion"
     testImplementation "org.apache.kafka:kafka-storage:$kafkaVersion"
     testImplementation 'commons-io:commons-io:2.11.0'
-    testImplementation "org.apache.zookeeper:zookeeper:${zookeeperVersion}"
     testOutput sourceSets.test.output
   }
 

config/cruise_control_jaas.conf_template

@@ -1,16 +1,4 @@
-//Rename this file to cruise_control_jaas.conf when using secured zookeepers
-//For detailed instructions, see /docs/wiki/User Guide/Secure-zookeeper-configuration.md
-
-//Enter appropriate Client entry for secured zookeeper client connections
-Client {
-  com.sun.security.auth.module.Krb5LoginModule required
-  useKeyTab=true
-  keyTab="/path/to/zookeeper_client.keytab"
-  storeKey=true
-  useTicketCache=false
-  principal="zookeeper_client@<REALM>";
-};
-
+//Rename this file to cruise_control_jaas.conf if security is enabled
 //Enter appropriate KafkaClient entry if using the SASL protocol, remove if not
 KafkaClient {
   com.sun.security.auth.module.Krb5LoginModule required

config/cruisecontrol.properties

@@ -173,12 +173,6 @@ num.proposal.precompute.threads=1
 # Configurations for the executor
 # =======================================
 
-# The zookeeper connect of the Kafka cluster
-zookeeper.connect=localhost:2181/
-
-# If true, appropriate zookeeper Client { .. } entry required in jaas file located at $base_dir/config/cruise_control_jaas.conf
-zookeeper.security.enabled=false
-
 # The max number of partitions to move in/out on a given broker at a given time.
 num.concurrent.partition.movements.per.broker=10
 
@@ -222,9 +216,6 @@ self.healing.exclude.recently.demoted.brokers=true
 # True if recently removed brokers are excluded from optimizations during self healing, false otherwise
 self.healing.exclude.recently.removed.brokers=true
 
-# The zk path to store failed broker information.
-failed.brokers.zk.path=/CruiseControlBrokerList
-
 # Topic config provider class
 topic.config.provider.class=com.linkedin.kafka.cruisecontrol.config.KafkaAdminTopicConfigProvider
 

cruise-control-core/src/test/resources/log4j2.properties

@@ -17,12 +17,5 @@ logger.orgApacheKafka.level=error
 logger.kafka.name=kafka
 logger.kafka.level=error
 
-# zkclient can be verbose, during debugging it is common to adjust is separately
-logger.zkclient.name=kafka.zk.KafkaZkClient
-logger.zkclient.level=warn
-
-logger.zookeeper.name=org.apache.zookeeper
-logger.zookeeper.level=warn
-
 rootLogger.appenderRefs=console
 rootLogger.appenderRef.console.ref=STDOUT

cruise-control-metrics-reporter/src/test/java/com/linkedin/kafka/cruisecontrol/metricsreporter/CruiseControlMetricsReporterTest.java

@@ -50,6 +50,7 @@
 import static com.linkedin.kafka.cruisecontrol.metricsreporter.metric.RawMetricType.*;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
 
 public class CruiseControlMetricsReporterTest extends CCKafkaClientsIntegrationTestHarness {
   protected static final String TOPIC = "CruiseControlMetricsReporterTest";
@@ -199,14 +200,26 @@ public void testUpdatingMetricsTopicConfig() throws ExecutionException, Interrup
     brokerConfig.put(CRUISE_CONTROL_METRICS_TOPIC_AUTO_CREATE_CONFIG, "true");
     brokerConfig.put(CRUISE_CONTROL_METRICS_TOPIC_NUM_PARTITIONS_CONFIG, "2");
     brokerConfig.put(CRUISE_CONTROL_METRICS_TOPIC_REPLICATION_FACTOR_CONFIG, "1");
-    CCEmbeddedBroker broker = new CCEmbeddedBroker(brokerConfig);
-    // Restart broker
-    broker.startup();
-    // Wait for broker to boot up
-    Thread.sleep(5000);
-    // Check whether the topic config is updated
-    topicDescription = adminClient.describeTopics(Collections.singleton(TOPIC)).values().get(TOPIC).get();
-    assertEquals(2, topicDescription.partitions().size());
+    try (CCEmbeddedBroker broker = new CCEmbeddedBroker(brokerConfig)) {
+      // Restart broker
+      broker.startup();
+      // Check whether the topic config is updated
+      long startTime = System.currentTimeMillis();
+      boolean isTopicConfigChanged = false;
+      while (!isTopicConfigChanged) {
+        if (System.currentTimeMillis() > startTime + 60000) {
+          fail("Topic config was not updated");
+        }
+
+        TopicDescription description = adminClient.describeTopics(Collections.singleton(TOPIC)).topicNameValues().get(TOPIC).get();
+        isTopicConfigChanged = 2 == description.partitions().size();
+
+        try {
+          Thread.sleep(5000);
+        } catch (InterruptedException ignored) {
+        }
+      }
+    }
   }
 
   @Test

cruise-control-metrics-reporter/src/test/java/com/linkedin/kafka/cruisecontrol/metricsreporter/utils/CCAbstractKRaftTestHarness.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2025 LinkedIn Corp. Licensed under the BSD 2-Clause License (the "License").
 See License in the project root for license information.
+ */
+package com.linkedin.kafka.cruisecontrol.metricsreporter.utils;
+
+public class CCAbstractKRaftTestHarness {
+    protected CCEmbeddedKRaftController _controller;
+
+    /**
+     * Setup the unit test.
+     */
+    public void setUp() {
+        if (_controller == null) {
+            _controller = new CCEmbeddedKRaftController();
+        }
+        _controller.startup();
+    }
+
+    /**
+     * Teardown the unit test.
+     */
+    public void tearDown() {
+        if (_controller != null) {
+            CCKafkaTestUtils.quietly(() -> _controller.close());
+            _controller = null;
+        }
+    }
+
+    protected CCEmbeddedKRaftController kraftController() {
+        return _controller;
+    }
+}

cruise-control-metrics-reporter/src/test/java/com/linkedin/kafka/cruisecontrol/metricsreporter/utils/CCEmbeddedBroker.java

@@ -5,51 +5,49 @@
 package com.linkedin.kafka.cruisecontrol.metricsreporter.utils;
 
 import java.io.File;
-import java.lang.reflect.Constructor;
-import java.lang.reflect.InvocationTargetException;
 import java.net.URI;
+import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
-import java.util.NoSuchElementException;
-import kafka.metrics.KafkaMetricsReporter;
 import kafka.server.KafkaConfig;
-import kafka.server.KafkaServer;
 import org.apache.commons.io.FileUtils;
 import org.apache.kafka.common.network.ListenerName;
 import org.apache.kafka.common.security.auth.SecurityProtocol;
 import org.apache.kafka.common.utils.Time;
 import org.apache.kafka.network.SocketServerConfigs;
-import org.apache.kafka.server.config.ServerConfigs;
+import org.apache.kafka.server.config.KRaftConfigs;
 import org.apache.kafka.server.config.ServerLogConfigs;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-import scala.Option;
-import scala.collection.Seq;
-import scala.collection.mutable.ArrayBuffer;
+
+import static com.linkedin.kafka.cruisecontrol.metricsreporter.utils.CCKafkaRaftServer.CLUSTER_ID_CONFIG;
 
 public class CCEmbeddedBroker implements AutoCloseable {
   private static final Logger LOG = LoggerFactory.getLogger(CCEmbeddedBroker.class);
   private final Map<SecurityProtocol, Integer> _ports;
   private final Map<SecurityProtocol, String> _hosts;
-  private final KafkaServer _kafkaServer;
+  private final CCKafkaRaftServer _kafkaServer;
   private int _id;
-  private File _logDir;
+  private final List<File> _logDirs;
+  private File _metadataLogDir;
 
   public CCEmbeddedBroker(Map<Object, Object> config) {
     _ports = new HashMap<>();
     _hosts = new HashMap<>();
+    _logDirs = new ArrayList<>();
 
     try {
       // Also validates the config
       KafkaConfig kafkaConfig = new KafkaConfig(config, true);
       parseConfigs(config);
 
-      _kafkaServer = createKafkaServer(kafkaConfig);
+      _kafkaServer = new CCKafkaRaftServer(kafkaConfig, config.get(CLUSTER_ID_CONFIG).toString(), Time.SYSTEM);
 
       startup();
       _ports.replaceAll((securityProtocol, port) -> {
         try {
-          return _kafkaServer.boundPort(ListenerName.forSecurityProtocol(securityProtocol));
+          return _kafkaServer.boundBrokerPort(ListenerName.forSecurityProtocol(securityProtocol));
         } catch (Exception e) {
           throw new IllegalStateException(e);
         }
@@ -59,46 +57,10 @@ public CCEmbeddedBroker(Map<Object, Object> config) {
     }
   }
 
-  /**
-   * Creates the {@link KafkaServer} instance using the appropriate constructor for the version of Kafka on the classpath.
-   * It will attempt to use the 2.8+ version first and then fall back to the 2.5+ version. If neither work, a
-   * {@link NoSuchElementException} will be thrown.
-   *
-   * @param kafkaConfig The {@link KafkaConfig} instance to be used to create the returned {@link KafkaServer} instance.
-   * @return A {@link KafkaServer} instance configured with the supplied {@link KafkaConfig}.
-   * @throws ClassNotFoundException If a version of {@link KafkaServer} cannot be found on the classpath.
-   */
-  private static KafkaServer createKafkaServer(KafkaConfig kafkaConfig) throws ClassNotFoundException {
-    // The KafkaServer constructor changed in 2.8, so we need to figure out which one we are using and invoke it with the correct parameters
-    KafkaServer kafkaServer = null;
-    Class<?> kafkaServerClass = Class.forName(KafkaServer.class.getName());
-
-    try {
-      Constructor<?> kafka28PlusCon = kafkaServerClass.getConstructor(KafkaConfig.class, Time.class, Option.class, boolean.class);
-      kafkaServer = (KafkaServer) kafka28PlusCon.newInstance(kafkaConfig, Time.SYSTEM, Option.empty(), false);
-    } catch (NoSuchMethodException | InvocationTargetException | InstantiationException | IllegalAccessException e) {
-      LOG.debug("Unable to find Kafka 2.8+ constructor for KafkaSever class", e);
-    }
-
-    if (kafkaServer == null) {
-      try {
-        Constructor<?> kafka25PlusCon = kafkaServerClass.getConstructor(KafkaConfig.class, Time.class, Option.class, Seq.class);
-        kafkaServer = (KafkaServer) kafka25PlusCon.newInstance(kafkaConfig, Time.SYSTEM, Option.empty(), new ArrayBuffer<KafkaMetricsReporter>());
-      } catch (NoSuchMethodException | InvocationTargetException | InstantiationException | IllegalAccessException e) {
-        LOG.debug("Unable to find Kafka 2.5+ constructor for KafkaSever class", e);
-      }
-    }
-
-    if (kafkaServer != null) {
-      return kafkaServer;
-    } else {
-      throw new NoSuchElementException("Unable to find viable constructor fo the KafkaServer class");
-    }
-  }
-
   private void parseConfigs(Map<Object, Object> config) {
-    _id = Integer.parseInt((String) config.get(ServerConfigs.BROKER_ID_CONFIG));
-    _logDir = new File((String) config.get(ServerLogConfigs.LOG_DIR_CONFIG));
+    readLogDirs(config);
+    _id = Integer.parseInt((String) config.get(KRaftConfigs.NODE_ID_CONFIG));
+    _metadataLogDir = new File((String) config.get(KRaftConfigs.METADATA_LOG_DIR_CONFIG));
 
     // Bind addresses
     String listenersString = (String) config.get(SocketServerConfigs.LISTENERS_CONFIG);
@@ -115,6 +77,14 @@ private void parseConfigs(Map<Object, Object> config) {
     }
   }
 
+  private void readLogDirs(Map<Object, Object> config) {
+    String logdir = (String) config.get(ServerLogConfigs.LOG_DIR_CONFIG);
+    String[] paths = logdir.split(",");
+    for (String path : paths) {
+      _logDirs.add(new File(path));
+    }
+  }
+
   public int id() {
     return _id;
   }
@@ -154,10 +124,9 @@ public void awaitShutdown() {
   public void close() {
     CCKafkaTestUtils.quietly(this::shutdown);
     CCKafkaTestUtils.quietly(this::awaitShutdown);
-    CCKafkaTestUtils.quietly(() -> FileUtils.forceDelete(_logDir));
-  }
-
-  public static CCEmbeddedBrokerBuilder newServer() {
-    return new CCEmbeddedBrokerBuilder();
+    CCKafkaTestUtils.quietly(() -> FileUtils.forceDelete(_metadataLogDir));
+    for (File logDir : _logDirs) {
+      CCKafkaTestUtils.quietly(() -> FileUtils.forceDelete(logDir));
+    }
   }
 }