/** * 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.server import kafka.utils._ import org.apache.zookeeper.Watcher.Event.KeeperState import org.I0Itec.zkclient.{IZkStateListener, ZkClient} import java.net.InetAddress /** * This class registers the broker in zookeeper to allow * other brokers and consumers to detect failures. It uses an ephemeral znode with the path: * /brokers/[0...N] --> advertisedHost:advertisedPort * * Right now our definition of health is fairly naive. If we register in zk we are healthy, otherwise * we are dead. */ class KafkaHealthcheck(private val brokerId: Int, private val advertisedHost: String, private val advertisedPort: Int, private val zkSessionTimeoutMs: Int, private val zkClient: ZkClient) extends Logging { val brokerIdPath = ZkUtils.BrokerIdsPath + "/" + brokerId val sessionExpireListener = new SessionExpireListener def startup() { zkClient.subscribeStateChanges(sessionExpireListener) register() } /** * Register this broker as "alive" in zookeeper */ def register() { val advertisedHostName = if(advertisedHost == null || advertisedHost.trim.isEmpty) InetAddress.getLocalHost.getCanonicalHostName else advertisedHost val jmxPort = System.getProperty("com.sun.management.jmxremote.port", "-1").toInt ZkUtils.registerBrokerInZk(zkClient, brokerId, advertisedHostName, advertisedPort, zkSessionTimeoutMs, jmxPort) } /** * When we get a SessionExpired event, we lost all ephemeral nodes and zkclient has reestablished a * connection for us. We need to re-register this broker in the broker registry. */ class SessionExpireListener() extends IZkStateListener { @throws(classOf[Exception]) def handleStateChanged(state: KeeperState) { // do nothing, since zkclient will do reconnect for us. } /** * Called after the zookeeper session has expired and a new session has been created. You would have to re-create * any ephemeral nodes here. * * @throws Exception * On any error. */ @throws(classOf[Exception]) def handleNewSession() { info("re-registering broker info in ZK for broker " + brokerId) register() info("done re-registering broker") info("Subscribing to %s path to watch for new topics".format(ZkUtils.BrokerTopicsPath)) } } }