Kafka 主函数在kafka.Kafka.scala 如下：

      val serverConfig = new KafkaConfig(props)KafkaMetricsReporter.startReporters(serverConfig.props)val kafkaServerStartble = new KafkaServerStartable(serverConfig)kafkaServerStartble.startup

读取命令行中第一个参数作为配置文件

bin/zookeeper-server-start.sh config/zookeeper.properties

kafka.utils.Utils从中读取配置项 生成props 作为KafkaConfig参数

KafkaConfig构造函数还是已VerifiableProperties作为参数

KafkaMetricsReporter调用startReporters(props)

class KafkaServerStartable(val serverConfig: KafkaConfig) extends Logging {private var server: KafkaServer = nulldef startup() {server.startup()}
}

KafkaServerStartable看上去就是一个KafkaServer ……  直接看kafka.server.KafkaServer吧

    /* start scheduler */kafkaScheduler.startup()/* setup zookeeper */zkClient = initZk()/* start log manager */logManager = createLogManager(zkClient)logManager.startup()socketServer = new SocketServer(config.brokerId,config.hostName,config.port,config.numNetworkThreads,config.queuedMaxRequests,config.socketSendBufferBytes,config.socketReceiveBufferBytes,config.socketRequestMaxBytes)socketServer.startup()replicaManager = new ReplicaManager(config, time, zkClient, kafkaScheduler, logManager, isShuttingDown)kafkaController = new KafkaController(config, zkClient)/* start processing requests */apis = new KafkaApis(socketServer.requestChannel, replicaManager, zkClient, config.brokerId, config, kafkaController)requestHandlerPool = new KafkaRequestHandlerPool(config.brokerId, socketServer.requestChannel, apis, config.numIoThreads)Mx4jLoader.maybeLoad()replicaManager.startup()kafkaController.startup()topicConfigManager = new TopicConfigManager(zkClient, logManager)topicConfigManager.startup()/* tell everyone we are alive */kafkaHealthcheck = new KafkaHealthcheck(config.brokerId, config.advertisedHostName, config.advertisedPort, config.zkSessionTimeoutMs, zkClient)kafkaHealthcheck.startup()registerStats()startupComplete.set(true);

读kafka源码到了这里，突然间有一种豁然开朗的感觉，

在这里先后启动了

KafkaScheduler、LogManager、SocketServer、ReplicaManager、KakfaController、KafkaApi ....

好戏~ 就此上演 待我~ 细说从头