创建SparkEnv获取ActorSystem的作用是什么？

创建SparkEnv获取ActorSystem,这一步的主要的作用是创建ActorSystem对象以后根据这个对象来创建相应的Actor

//TODO 该方法创建了一个SparkEnv private[spark] def createSparkEnv( conf: SparkConf, isLocal: Boolean, listenerBus: LiveListenerBus): SparkEnv = { SparkEnv.createDriverEnv(conf, isLocal, listenerBus) }

主要调用SparkEnv类的createDriverEnv()方法获取SparkEnv对象,createDriverEnv()主要调用SparkEnv的create()方法，这里代码大约

在SparkEnv的154行，代码具体如下:

private[spark] def createDriverEnv( conf: SparkConf, isLocal: Boolean, listenerBus: LiveListenerBus, mockOutputCommitCoordinator: Option[OutputCommitCoordinator] = None): SparkEnv = { assert(conf.contains("spark.driver.host"), "spark.driver.host is not set on the driver!") assert(conf.contains("spark.driver.port"), "spark.driver.port is not set on the driver!") val hostname = conf.get("spark.driver.host") val port = conf.get("spark.driver.port").toInt //TODO 调用create()方法 create( conf, SparkContext.DRIVER_IDENTIFIER, hostname, port, isDriver = true, isLocal = isLocal, listenerBus = listenerBus, mockOutputCommitCoordinator = mockOutputCommitCoordinator ) }

createDriverEnv()内部主要调用create()方法,重要的代码如下:

// Create the ActorSystem for Akka and get the port it binds to. val (actorSystem, boundPort) = { val actorSystemName = if (isDriver) driverActorSystemName else executorActorSystemName //TODO 利用AkkaUtils这个工具类创建ActorSystem AkkaUtils.createActorSystem(actorSystemName, hostname, port, conf, securityManager) }

这个方法的主要作用是调用AkkaUtils这个工具类创建ActorSystem。