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From: andrewor14 <git@git.apache.org>
To: reviews@spark.apache.org
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References: <git-pr-5144-spark@git.apache.org>
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Subject: [GitHub] spark pull request: [SPARK-5338][MESOS] Add cluster mode
 support f...
Content-Type: text/plain
Message-Id: <20150415215343.8BAD2E0922@git1-us-west.apache.org>
Date: Wed, 15 Apr 2015 21:53:43 +0000 (UTC)

Github user andrewor14 commented on a diff in the pull request:

    https://github.com/apache/spark/pull/5144#discussion_r28466970
  
    --- Diff: core/src/main/scala/org/apache/spark/scheduler/cluster/mesos/MesosClusterScheduler.scala ---
    @@ -0,0 +1,614 @@
    +/*
    + * 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 org.apache.spark.scheduler.cluster.mesos
    +
    +import java.io.File
    +import java.util.concurrent.locks.ReentrantLock
    +import java.util.{Collections, Date, List => JList}
    +
    +import org.apache.mesos.Protos.Environment.Variable
    +import org.apache.mesos.Protos.TaskStatus.Reason
    +import org.apache.mesos.Protos.{TaskState => MesosTaskState, _}
    +import org.apache.mesos.{Scheduler, SchedulerDriver}
    +import org.apache.spark.deploy.mesos.MesosDriverDescription
    +import org.apache.spark.deploy.rest.{CreateSubmissionResponse, KillSubmissionResponse, SubmissionStatusResponse}
    +import org.apache.spark.metrics.MetricsSystem
    +import org.apache.spark.util.Utils
    +import org.apache.spark.{SecurityManager, SparkConf, SparkException, TaskState}
    +
    +import scala.collection.JavaConversions._
    +import scala.collection.mutable
    +import scala.collection.mutable.ArrayBuffer
    +
    +
    +/**
    + * Tracks the current state of a Mesos Task that runs a Spark driver.
    + * @param submission Submitted driver description from
    + *                   [[org.apache.spark.deploy.rest.mesos.MesosRestServer]]
    + * @param taskId Mesos TaskID generated for the task
    + * @param slaveId Slave ID that the task is assigned to
    + * @param taskState The last known task status update.
    + * @param startDate The date the task was launched
    + */
    +private[spark] class MesosClusterTaskState(
    +    val submission: MesosDriverDescription,
    +    val taskId: TaskID,
    +    val slaveId: SlaveID,
    +    var taskState: Option[TaskStatus],
    +    var startDate: Date)
    +  extends Serializable {
    +
    +  def copy(): MesosClusterTaskState = {
    +    new MesosClusterTaskState(
    +      submission, taskId, slaveId, taskState, startDate)
    +  }
    +}
    +
    +/**
    + * Tracks the retry state of a driver, which includes the next time it should be scheduled
    + * and necessary information to do exponential backoff.
    + * This class is not thread-safe, and we expect the caller to handle synchronizing state.
    + * @param lastFailureStatus Last Task status when it failed.
    + * @param retries Number of times it has retried.
    + * @param nextRetry Next retry time to be scheduled.
    + * @param waitTime The amount of time driver is scheduled to wait until next retry.
    + */
    +private[spark] class RetryState(
    +    val lastFailureStatus: TaskStatus,
    +    val retries: Int,
    +    val nextRetry: Date,
    +    val waitTime: Int) extends Serializable {
    +  def copy(): RetryState =
    +    new RetryState(lastFailureStatus, retries, nextRetry, waitTime)
    +}
    +
    +/**
    + * The full state of the cluster scheduler, currently being used for displaying
    + * information on the UI.
    + * @param frameworkId Mesos Framework id for the cluster scheduler.
    + * @param masterUrl The Mesos master url
    + * @param queuedDrivers All drivers queued to be launched
    + * @param launchedDrivers All launched or running drivers
    + * @param finishedDrivers All terminated drivers
    + * @param retryList All drivers pending to be retried
    + */
    +private[spark] class MesosClusterSchedulerState(
    +    val frameworkId: String,
    +    val masterUrl: Option[String],
    +    val queuedDrivers: Iterable[MesosDriverDescription],
    +    val launchedDrivers: Iterable[MesosClusterTaskState],
    +    val finishedDrivers: Iterable[MesosClusterTaskState],
    +    val retryList: Iterable[MesosDriverDescription])
    +
    +/**
    + * A Mesos scheduler that is responsible for launching submitted Spark drivers in cluster mode
    + * as Mesos tasks in a Mesos cluster.
    + * All drivers are launched asynchronously by the framework, which will eventually be launched
    + * by one of the slaves in the cluster. The results of the driver will be stored in slave's task
    + * sandbox which is accessible by visiting the Mesos UI.
    + * This scheduler supports recovery by persisting all its state and performs task reconciliation
    + * on recover, which gets all the latest state for all the drivers from Mesos master.
    + */
    +private[spark] class MesosClusterScheduler(
    +    engineFactory: MesosClusterPersistenceEngineFactory,
    +    conf: SparkConf)
    +  extends Scheduler with MesosSchedulerUtils {
    +  var frameworkUrl: String = _
    +
    +  private val metricsSystem =
    +    MetricsSystem.createMetricsSystem("mesos_cluster", conf, new SecurityManager(conf))
    +  private val master = conf.get("spark.master")
    +  private val appName = conf.get("spark.app.name")
    +  private val queuedCapacity = conf.getInt("spark.deploy.mesos.queuedDrivers", 200)
    +  private val retainedDrivers = conf.getInt("spark.deploy.retainedDrivers", 200)
    +  private val maxRetryWaitTime = conf.getInt("spark.mesos.cluster.retry.wait.max", 60) // 1 minute
    +  private val schedulerState = engineFactory.createEngine("scheduler")
    +  private val stateLock = new ReentrantLock()
    +  private val finishedDrivers = new mutable.ArrayBuffer[MesosClusterTaskState](retainedDrivers)
    +  private var frameworkId: String = null
    +  val launchedDrivers = new mutable.HashMap[String, MesosClusterTaskState]()
    +  // Holds the list of tasks that needs to reconcile with Mesos master.
    +  // All states that are loaded after failover are added here.
    +  private val pendingRecover = new mutable.HashMap[String, SlaveID]()
    +  // A queue that stores all the submitted drivers that hasn't been launched.
    +  val queuedDrivers = new ArrayBuffer[MesosDriverDescription]()
    +  // All supervised drivers that are waiting to retry after termination.
    +  val pendingRetryDrivers = new ArrayBuffer[MesosDriverDescription]()
    +  private val queuedDriversState = engineFactory.createEngine("driverQueue")
    +  private val launchedDriversState = engineFactory.createEngine("launchedDrivers")
    +  private val pendingRetryDriversState = engineFactory.createEngine("retryList")
    +  // Flag to mark if the scheduler is ready to be called, which is until the scheduler
    +  // is registered with Mesos master.
    +  protected var ready = false
    +  private var masterInfo: Option[MasterInfo] = None
    +
    +  private def isQueueFull(): Boolean = launchedDrivers.size >= queuedCapacity
    +
    +  def submitDriver(desc: MesosDriverDescription): CreateSubmissionResponse = {
    +    val c = new CreateSubmissionResponse
    +    if (!ready) {
    +      c.success = false
    +      c.message = "Scheduler is not ready to take requests"
    +      return c
    +    }
    +
    +    stateLock.synchronized {
    +      if (isQueueFull()) {
    +        c.success = false
    +        c.message = "Already reached maximum submission size"
    +      }
    +      c.submissionId = desc.submissionId
    +      queuedDrivers += desc
    +      c.success = true
    +    }
    +    c
    +  }
    +
    +  private def removeFromQueuedDrivers(id: String): Boolean = {
    +    val index = queuedDrivers.indexWhere(_.submissionId.equals(id))
    +    if (index != -1) {
    +      queuedDrivers.remove(index)
    +      queuedDriversState.expunge(id)
    +      true
    +    } else {
    +      false
    +    }
    +  }
    +
    +  private def removeFromLaunchedDrivers(id: String): Boolean = {
    +    if (launchedDrivers.remove(id).isDefined) {
    +      launchedDriversState.expunge(id)
    +      true
    +    } else {
    +      false
    +    }
    +  }
    +
    +  private def removeFromPendingRetryDrivers(id: String): Boolean = {
    +    val index = pendingRetryDrivers.indexWhere(_.submissionId.equals(id))
    +    if (index != -1) {
    +      pendingRetryDrivers.remove(index)
    +      pendingRetryDriversState.expunge(id)
    +      true
    +    } else {
    +      false
    +    }
    +  }
    +
    +  def killDriver(submissionId: String): KillSubmissionResponse = {
    +    val k = new KillSubmissionResponse
    +    if (!ready) {
    +      k.success = false
    +      k.message = "Scheduler is not ready to take requests"
    +      return k
    +    }
    +    k.submissionId = submissionId
    +    stateLock.synchronized {
    +      // We look for the requested driver in the following places:
    +      // 1. Check if submission is running or launched.
    +      // 2. Check if it's still queued.
    +      // 3. Check if it's in the retry list.
    +      // 4. Check if it has already completed.
    +      if (launchedDrivers.contains(submissionId)) {
    +        val task = launchedDrivers(submissionId)
    +        driver.killTask(task.taskId)
    +        k.success = true
    +        k.message = "Killing running driver"
    +      } else if (removeFromQueuedDrivers(submissionId)) {
    +        k.success = true
    +        k.message = "Removed driver while it's still pending"
    +      } else if (removeFromPendingRetryDrivers(submissionId)) {
    +        k.success = true
    +        k.message = "Removed driver while it's retrying"
    +      } else if (finishedDrivers.exists(_.submission.submissionId.equals(submissionId))) {
    +        k.success = false
    +        k.message = "Driver already terminated"
    +      } else {
    +        k.success = false
    +        k.message = "Cannot find driver"
    +      }
    +    }
    +    k
    +  }
    +
    +  /**
    +   * Recover scheduler state that is persisted.
    +   * We still need to do task reconciliation to be up to date of the latest task states
    +   * as it might have changed while the scheduler is failing over.
    +   */
    +  private def recoverState(): Unit = {
    +    stateLock.synchronized {
    +      launchedDriversState.fetchAll[MesosClusterTaskState]().foreach { state =>
    +        launchedDrivers(state.taskId.getValue) = state
    +        pendingRecover(state.taskId.getValue) = state.slaveId
    +      }
    +      queuedDriversState.fetchAll[MesosDriverDescription]().foreach(d => queuedDrivers += d)
    +      // There is potential timing issue where a queued driver might have been launched
    +      // but the scheduler shuts down before the queued driver was able to be removed
    +      // from the queue. We try to mitigate this issue by walking through all queued drivers
    +      // and remove if they're already launched.
    +      queuedDrivers
    +        .filter(d => launchedDrivers.contains(d.submissionId))
    +        .toSeq
    +        .foreach(d => removeFromQueuedDrivers(d.submissionId))
    +      pendingRetryDriversState.fetchAll[MesosDriverDescription]()
    +        .foreach(s => pendingRetryDrivers += s)
    +      // TODO: Consider storing finished drivers so we can show them on the UI after
    +      // failover. For now we clear the history on each recovery.
    +      finishedDrivers.clear()
    +    }
    +  }
    +
    +  /**
    +   * Starts the cluster scheduler and wait until the scheduler is registered.
    +   * This also marks the scheduler to be ready for requests.
    +   */
    +  def start(): Unit = {
    +    // TODO: Implement leader election to make sure only one framework running in the cluster.
    +    val fwId = schedulerState.fetch[String]("frameworkId")
    +    val builder = FrameworkInfo.newBuilder()
    +      .setUser(Utils.getCurrentUserName())
    +      .setName(appName)
    +      .setWebuiUrl(frameworkUrl)
    +      .setCheckpoint(true)
    +      .setFailoverTimeout(Integer.MAX_VALUE) // Setting to max so tasks keep running on crash
    +    fwId.foreach { id =>
    +      builder.setId(FrameworkID.newBuilder().setValue(id).build())
    +      frameworkId = id
    +    }
    +    recoverState()
    +    metricsSystem.registerSource(new MesosClusterSchedulerSource(this))
    +    metricsSystem.start()
    +    startScheduler(
    +      "MesosClusterScheduler", master, MesosClusterScheduler.this, builder.build())
    +    ready = true
    +  }
    +
    +  def stop(): Unit = {
    +    ready = false
    +    metricsSystem.report()
    +    metricsSystem.stop()
    +    driver.stop(true)
    +  }
    +
    +  override def registered(
    +      driver: SchedulerDriver,
    +      newFrameworkId: FrameworkID,
    +      masterInfo: MasterInfo): Unit = {
    +    logInfo("Registered as framework ID " + newFrameworkId.getValue)
    +    if (newFrameworkId.getValue != frameworkId) {
    +      frameworkId = newFrameworkId.getValue
    +      schedulerState.persist("frameworkId", frameworkId)
    +    }
    +    markRegistered()
    +
    +    stateLock.synchronized {
    +      this.masterInfo = Some(masterInfo)
    +      if (!pendingRecover.isEmpty) {
    +        // Start task reconciliation if we need to recover.
    +        val statuses = pendingRecover.collect {
    +          case (taskId, slaveId) =>
    +            val newStatus = TaskStatus.newBuilder()
    +              .setTaskId(TaskID.newBuilder().setValue(taskId).build())
    +              .setSlaveId(slaveId)
    +              .setState(MesosTaskState.TASK_STAGING)
    +              .build()
    +            launchedDrivers.get(taskId).map(_.taskState.getOrElse(newStatus))
    +              .getOrElse(newStatus)
    +        }
    +        // TODO: Page the status updates to avoid trying to reconcile
    +        // a large amount of tasks at once.
    +        driver.reconcileTasks(statuses)
    +      }
    +    }
    +  }
    +
    +  private def buildDriverCommand(desc: MesosDriverDescription): CommandInfo = {
    +    val appJar = CommandInfo.URI.newBuilder()
    +      .setValue(desc.jarUrl.stripPrefix("file:").stripPrefix("local:")).build()
    +    val builder = CommandInfo.newBuilder().addUris(appJar)
    +    val entries =
    +      (conf.getOption("spark.executor.extraLibraryPath").toList ++
    +        desc.command.libraryPathEntries)
    +    val prefixEnv = if (!entries.isEmpty) {
    +      Utils.libraryPathEnvPrefix(entries)
    +    } else {
    +      ""
    +    }
    +    val envBuilder = Environment.newBuilder()
    +    desc.command.environment.foreach { case (k, v) =>
    +      envBuilder.addVariables(Variable.newBuilder().setName(k).setValue(v).build())
    +    }
    +    // Pass all spark properties to executor.
    +    val executorOpts = desc.schedulerProperties.map { case (k, v) => s"-D$k=$v" }.mkString(" ")
    +    envBuilder.addVariables(
    +      Variable.newBuilder().setName("SPARK_EXECUTOR_OPTS").setValue(executorOpts))
    +    val cmdOptions = generateCmdOption(desc)
    +    val executorUri = desc.schedulerProperties.get("spark.executor.uri")
    +      .orElse(desc.command.environment.get("SPARK_EXECUTOR_URI"))
    +    val appArguments = desc.command.arguments.mkString(" ")
    +    val cmd = if (executorUri.isDefined) {
    +      builder.addUris(CommandInfo.URI.newBuilder().setValue(executorUri.get).build())
    +      val folderBasename = executorUri.get.split('/').last.split('.').head
    +      val cmdExecutable = s"cd $folderBasename*; $prefixEnv bin/spark-submit"
    +      val cmdJar = s"../${desc.jarUrl.split("/").last}"
    +      s"$cmdExecutable ${cmdOptions.mkString(" ")} $cmdJar $appArguments"
    +    } else {
    +      val executorSparkHome = desc.schedulerProperties.get("spark.mesos.executor.home")
    +        .orElse(conf.getOption("spark.home"))
    +        .orElse(Option(System.getenv("SPARK_HOME")))
    +        .getOrElse {
    +          throw new SparkException("Executor Spark home `spark.mesos.executor.home` is not set!")
    +        }
    +      val cmdExecutable = new File(executorSparkHome, "./bin/spark-submit").getCanonicalPath
    +      val cmdJar = desc.jarUrl.split("/").last
    +      s"$cmdExecutable ${cmdOptions.mkString(" ")} $cmdJar $appArguments"
    +    }
    +    builder.setValue(cmd)
    +    builder.setEnvironment(envBuilder.build())
    +    builder.build()
    +  }
    +
    +  private def generateCmdOption(desc: MesosDriverDescription): Seq[String] = {
    +    var options = Seq(
    +      "--name", desc.schedulerProperties("spark.app.name"),
    +      "--class", desc.command.mainClass,
    +      "--master", s"mesos://${conf.get("spark.master")}",
    +      "--driver-cores", desc.cores.toString,
    +      "--driver-memory", s"${desc.mem}M")
    +    desc.schedulerProperties.get("spark.executor.memory").map { v =>
    +      options ++= Seq("--executor-memory", v)
    +    }
    +    desc.schedulerProperties.get("spark.cores.max").map { v =>
    +      options ++= Seq("--total-executor-cores", v)
    +    }
    +    options
    +  }
    +
    +  private class ResourceOffer(val offer: Offer, var cpu: Double, var mem: Double) {
    +    override def toString(): String = {
    +      s"Offer id: ${offer.getId.getValue}, cpu: $cpu, mem: $mem"
    +    }
    +  }
    +
    +  /**
    +   * This method takes all the possible candidates provided by the tasksFunc
    +   * and attempt to schedule them with Mesos offers.
    +   * Every time a new task is scheduled, the scheduledCallback is called to
    +   * perform post scheduled logic on each task.
    +   */
    +  private def scheduleTasks(
    +      candidates: Seq[MesosDriverDescription],
    +      scheduledCallback: (String) => Boolean,
    +      currentOffers: List[ResourceOffer],
    +      tasks: mutable.HashMap[OfferID, ArrayBuffer[TaskInfo]],
    +      currentTime: Date): Unit = {
    +    for (submission <- candidates) {
    +      val driverCpu = submission.cores
    +      val driverMem = submission.mem
    +      logTrace(s"Finding offer to launch driver with cpu: $driverCpu, mem: $driverMem")
    +      val offerOption = currentOffers.find { o =>
    +        o.cpu >= driverCpu && o.mem >= driverMem
    +      }
    +      if (offerOption.isEmpty) {
    +        logDebug(s"Unable to find offer to launch driver id: ${submission.submissionId}," +
    +          s"cpu: $driverCpu, mem: $driverMem")
    +      } else {
    +        val offer = offerOption.get
    +        offer.cpu -= driverCpu
    +        offer.mem -= driverMem
    +        val taskId = TaskID.newBuilder().setValue(submission.submissionId).build()
    +        val cpuResource = Resource.newBuilder()
    +          .setName("cpus").setType(Value.Type.SCALAR)
    +          .setScalar(Value.Scalar.newBuilder().setValue(driverCpu)).build()
    +        val memResource = Resource.newBuilder()
    +          .setName("mem").setType(Value.Type.SCALAR)
    +          .setScalar(Value.Scalar.newBuilder().setValue(driverMem)).build()
    +        val commandInfo = buildDriverCommand(submission)
    +        val appName = submission.schedulerProperties("spark.app.name")
    +        val taskInfo = TaskInfo.newBuilder()
    +          .setTaskId(taskId)
    +          .setName(s"Driver for $appName")
    +          .setSlaveId(offer.offer.getSlaveId)
    +          .setCommand(commandInfo)
    +          .addResources(cpuResource)
    +          .addResources(memResource)
    +          .build()
    +        val queuedTasks = if (!tasks.contains(offer.offer.getId)) {
    +          val buffer = new ArrayBuffer[TaskInfo]
    +          tasks(offer.offer.getId) = buffer
    +          buffer
    +        } else {
    +          tasks(offer.offer.getId)
    +        }
    +        queuedTasks += taskInfo
    +        logTrace(s"Using offer ${offer.offer.getId.getValue} to launch driver " +
    +          submission.submissionId)
    +        val newState = new MesosClusterTaskState(submission, taskId, offer.offer.getSlaveId,
    +          None, new Date())
    +        launchedDrivers(submission.submissionId) = newState
    +        launchedDriversState.persist(submission.submissionId, newState)
    +        scheduledCallback(submission.submissionId)
    +      }
    +    }
    +  }
    +
    +  override def resourceOffers(driver: SchedulerDriver, offers: JList[Offer]): Unit = {
    +    /**
    +     * Prints the list of Mesos offers for logging purpose.
    +     */
    +    def printOffers(offers: Iterable[ResourceOffer]): String = {
    +      val builder = new StringBuilder()
    +      offers.foreach { o =>
    +        builder.append(o).append("\n")
    +      }
    +      builder.toString()
    +    }
    +    val currentOffers = offers.map { o =>
    +      new ResourceOffer(
    +        o, getResource(o.getResourcesList, "cpus"), getResource(o.getResourcesList, "mem"))
    +    }.toList
    +    logTrace(s"Received offers from Mesos: \n${printOffers(currentOffers)}")
    +    val tasks = new mutable.HashMap[OfferID, ArrayBuffer[TaskInfo]]()
    +    val currentTime = new Date()
    +
    +    stateLock.synchronized {
    +      // We first schedule all the supervised drivers that are ready to retry.
    +      // This list will be empty if none of the drivers are marked as supervise.
    +      scheduleTasks(pendingRetryDrivers
    +        .filter(d => d.retryState.get.nextRetry.before(currentTime)),
    +        removeFromPendingRetryDrivers,
    +        currentOffers, tasks, currentTime)
    +      // Then we walk through the queued drivers and try to schedule them.
    +      scheduleTasks(queuedDrivers,
    +        removeFromQueuedDrivers,
    +        currentOffers, tasks, currentTime)
    +    }
    +    tasks.foreach { case (offerId, tasks) =>
    +      driver.launchTasks(Collections.singleton(offerId), tasks)
    +    }
    +    offers
    +      .filter(o => !tasks.keySet.contains(o.getId))
    +      .foreach(o => driver.declineOffer(o.getId))
    +  }
    +
    +  def getState(): MesosClusterSchedulerState = {
    +    def copyBuffer(
    +      buffer: ArrayBuffer[MesosDriverDescription]): ArrayBuffer[MesosDriverDescription] = {
    +      val newBuffer = new ArrayBuffer[MesosDriverDescription](buffer.size)
    +      buffer.copyToBuffer(newBuffer)
    +      newBuffer
    +    }
    +    stateLock.synchronized {
    +      new MesosClusterSchedulerState(
    +        frameworkId,
    +        masterInfo.map(m => s"http://${m.getIp}:${m.getPort}"),
    +        copyBuffer(queuedDrivers),
    +        launchedDrivers.values.map(_.copy).toList,
    +        finishedDrivers.map(_.copy).toList,
    +        copyBuffer(pendingRetryDrivers))
    +    }
    +  }
    +
    +  def getStatus(submissionId: String): SubmissionStatusResponse = {
    +    val s = new SubmissionStatusResponse
    +    if (!ready) {
    +      s.success = false
    +      s.message = "Scheduler is not ready to take requests"
    +      return s
    +    }
    +    s.submissionId = submissionId
    +    stateLock.synchronized {
    +      if (queuedDrivers.exists(_.submissionId.equals(submissionId))) {
    +        s.success = true
    +        s.driverState = "Driver is queued for launch"
    --- End diff --
    
    I think `driverState` here should be something like `QUEUED`, `RUNNING`, `FINISHED`, `RETRYING` or `NOT_FOUND`. I'm OK with just leaving these as strings (and not making an enum) since we don't really use these values on the client side.


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