Worker启动源码分析

Youtube视频分享

• youtube: https://youtu.be/ll_Ae6rP7II

start-slave.sh启动脚本

• worker启动脚本跟master一样，都调用spark-daemon.sh，只是启动类不一样

CLASS="org.apache.spark.deploy.worker.Worker"
spark-daemon.sh start $CLASS 

Worker main入口

主要源码

• 启动 'sparkWorker' 的服务

def main(argStrings: Array[String]) {
    Utils.initDaemon(log)
    val conf = new SparkConf
    val args = new WorkerArguments(argStrings, conf)
    val rpcEnv = startRpcEnvAndEndpoint(args.host, args.port, args.webUiPort, args.cores,
      args.memory, args.masters, args.workDir, conf = conf)
    rpcEnv.awaitTermination()
  }

  def startRpcEnvAndEndpoint(
      host: String,
      port: Int,
      webUiPort: Int,
      cores: Int,
      memory: Int,
      masterUrls: Array[String],
      workDir: String,
      workerNumber: Option[Int] = None,
      conf: SparkConf = new SparkConf): RpcEnv = {

    // The LocalSparkCluster runs multiple local sparkWorkerX RPC Environments
    val systemName = SYSTEM_NAME + workerNumber.map(_.toString).getOrElse("")
    val securityMgr = new SecurityManager(conf)
    val rpcEnv = RpcEnv.create(systemName, host, port, conf, securityMgr)
    val masterAddresses = masterUrls.map(RpcAddress.fromSparkURL(_))
    rpcEnv.setupEndpoint(ENDPOINT_NAME, new Worker(rpcEnv, webUiPort, cores, memory,
      masterAddresses, systemName, ENDPOINT_NAME, workDir, conf, securityMgr))
    rpcEnv
  }

Worker onStart方法调用

WorkUI

• 启动WorkerUI

向所有master注册

• 线程池中每个master单独一个线程，向master注册worker

• worker通过 masterEndpoint.ask向master发送注册worker消息 : RegisterWorker

• master 接收到消息(RegisterWorker)处理后，回应worker消息 : RegisteredWorker

• worker收到RegisteredWorker消息后，进行 registered = true,和刷新内存中的master信息

 override def onStart() {
    assert(!registered)
    logInfo("Starting Spark worker %s:%d with %d cores, %s RAM".format(
      host, port, cores, Utils.megabytesToString(memory)))
    logInfo(s"Running Spark version ${org.apache.spark.SPARK_VERSION}")
    logInfo("Spark home: " + sparkHome)
    createWorkDir()
    shuffleService.startIfEnabled()
    webUi = new WorkerWebUI(this, workDir, webUiPort)
    webUi.bind()

    val scheme = if (webUi.sslOptions.enabled) "https" else "http"
    workerWebUiUrl = s"$scheme://$publicAddress:${webUi.boundPort}"
    registerWithMaster()

    metricsSystem.registerSource(workerSource)
    metricsSystem.start()
    // Attach the worker metrics servlet handler to the web ui after the metrics system is started.
    metricsSystem.getServletHandlers.foreach(webUi.attachHandler)
  }

 private def registerWithMaster() {
    // onDisconnected may be triggered multiple times, so don't attempt registration
    // if there are outstanding registration attempts scheduled.
    registrationRetryTimer match {
      case None =>
        registered = false
        registerMasterFutures = tryRegisterAllMasters()
        connectionAttemptCount = 0
        registrationRetryTimer = Some(forwordMessageScheduler.scxheduleAtFixedRate(
          new Runnable {
            override def run(): Unit = Utils.tryLogNonFatalError {
              Option(self).foreach(_.send(ReregisterWithMaster))
            }
          },
          INITIAL_REGISTRATION_RETRY_INTERVAL_SECONDS,
          INITIAL_REGISTRATION_RETRY_INTERVAL_SECONDS,
          TimeUnit.SECONDS))
      case Some(_) =>
        logInfo("Not spawning another attempt to register with the master, since there is an" +
          " attempt scheduled already.")
    }
  }

  private def registerWithMaster(masterEndpoint: RpcEndpointRef): Unit = {
    masterEndpoint.ask[RegisterWorkerResponse](RegisterWorker(
      workerId, host, port, self, cores, memory, workerWebUiUrl))
      .onComplete {
        // This is a very fast action so we can use "ThreadUtils.sameThread"
        case Success(msg) =>
          Utils.tryLogNonFatalError {
            handleRegisterResponse(msg)
          }
        case Failure(e) =>
          logError(s"Cannot register with master: ${masterEndpoint.address}", e)
          System.exit(1)
      }(ThreadUtils.sameThread)
  }

  private def handleRegisterResponse(msg: RegisterWorkerResponse): Unit = synchronized {
    msg match {
      case RegisteredWorker(masterRef, masterWebUiUrl) =>
        logInfo("Successfully registered with master " + masterRef.address.toSparkURL)
        registered = true
        changeMaster(masterRef, masterWebUiUrl)
        forwordMessageScheduler.scheduleAtFixedRate(new Runnable {
          override def run(): Unit = Utils.tryLogNonFatalError {
            self.send(SendHeartbeat)
          }
        }, 0, HEARTBEAT_MILLIS, TimeUnit.MILLISECONDS)
        if (CLEANUP_ENABLED) {
          logInfo(
            s"Worker cleanup enabled; old application directories will be deleted in: $workDir")
          forwordMessageScheduler.scheduleAtFixedRate(new Runnable {
            override def run(): Unit = Utils.tryLogNonFatalError {
              self.send(WorkDirCleanup)
            }
          }, CLEANUP_INTERVAL_MILLIS, CLEANUP_INTERVAL_MILLIS, TimeUnit.MILLISECONDS)
        }

      case RegisterWorkerFailed(message) =>
        if (!registered) {
          logError("Worker registration failed: " + message)
          System.exit(1)
        }

      case MasterInStandby =>
        // Ignore. Master not yet ready.
    }
  }