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From vanzin <...@git.apache.org>
Subject [GitHub] spark pull request #19468: [SPARK-18278] [Scheduler] Spark on Kubernetes - B...
Date Tue, 14 Nov 2017 00:43:43 GMT
Github user vanzin commented on a diff in the pull request:

    https://github.com/apache/spark/pull/19468#discussion_r150708127
  
    --- Diff: resource-managers/kubernetes/core/src/main/scala/org/apache/spark/scheduler/cluster/k8s/KubernetesClusterSchedulerBackend.scala
---
    @@ -0,0 +1,427 @@
    +/*
    + * 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.k8s
    +
    +import java.io.Closeable
    +import java.net.InetAddress
    +import java.util.concurrent.{ConcurrentHashMap, ExecutorService, ScheduledExecutorService,
TimeUnit}
    +import java.util.concurrent.atomic.{AtomicInteger, AtomicLong, AtomicReference}
    +import javax.annotation.concurrent.GuardedBy
    +
    +import io.fabric8.kubernetes.api.model._
    +import io.fabric8.kubernetes.client.{KubernetesClient, KubernetesClientException, Watcher}
    +import io.fabric8.kubernetes.client.Watcher.Action
    +import scala.collection.JavaConverters._
    +import scala.collection.mutable
    +import scala.concurrent.{ExecutionContext, Future}
    +
    +import org.apache.spark.SparkException
    +import org.apache.spark.deploy.k8s.config._
    +import org.apache.spark.deploy.k8s.constants._
    +import org.apache.spark.rpc.{RpcAddress, RpcEndpointAddress, RpcEnv}
    +import org.apache.spark.scheduler.{ExecutorExited, SlaveLost, TaskSchedulerImpl}
    +import org.apache.spark.scheduler.cluster.{CoarseGrainedSchedulerBackend, SchedulerBackendUtils}
    +import org.apache.spark.util.Utils
    +
    +private[spark] class KubernetesClusterSchedulerBackend(
    +    scheduler: TaskSchedulerImpl,
    +    rpcEnv: RpcEnv,
    +    executorPodFactory: ExecutorPodFactory,
    +    kubernetesClient: KubernetesClient,
    +    allocatorExecutor: ScheduledExecutorService,
    +    requestExecutorsService: ExecutorService)
    +  extends CoarseGrainedSchedulerBackend(scheduler, rpcEnv) {
    +
    +  import KubernetesClusterSchedulerBackend._
    +
    +  private val EXECUTOR_ID_COUNTER = new AtomicLong(0L)
    +  private val RUNNING_EXECUTOR_PODS_LOCK = new Object
    +  @GuardedBy("RUNNING_EXECUTOR_PODS_LOCK")
    +  private val runningExecutorsToPods = new mutable.HashMap[String, Pod]
    +  private val executorPodsByIPs = new ConcurrentHashMap[String, Pod]()
    +  private val podsWithKnownExitReasons = new ConcurrentHashMap[String, ExecutorExited]()
    +  private val disconnectedPodsByExecutorIdPendingRemoval = new ConcurrentHashMap[String,
Pod]()
    +
    +  private val kubernetesNamespace = conf.get(KUBERNETES_NAMESPACE)
    +
    +  private val kubernetesDriverPodName = conf
    +    .get(KUBERNETES_DRIVER_POD_NAME)
    +    .getOrElse(throw new SparkException("Must specify the driver pod name"))
    +  private implicit val requestExecutorContext = ExecutionContext.fromExecutorService(
    +    requestExecutorsService)
    +
    +  private val driverPod = kubernetesClient.pods()
    +    .inNamespace(kubernetesNamespace)
    +    .withName(kubernetesDriverPodName)
    +    .get()
    +
    +  override val minRegisteredRatio =
    +    if (conf.getOption("spark.scheduler.minRegisteredResourcesRatio").isEmpty) {
    +      0.8
    +    } else {
    +      super.minRegisteredRatio
    +    }
    +
    +  private val executorWatchResource = new AtomicReference[Closeable]
    +  protected val totalExpectedExecutors = new AtomicInteger(0)
    +
    +  private val driverUrl = RpcEndpointAddress(
    +    conf.get("spark.driver.host"),
    +    conf.getInt("spark.driver.port", DEFAULT_DRIVER_PORT),
    +    CoarseGrainedSchedulerBackend.ENDPOINT_NAME).toString
    +
    +  private val initialExecutors = SchedulerBackendUtils.getInitialTargetExecutorNumber(conf)
    +
    +  private val podAllocationInterval = conf.get(KUBERNETES_ALLOCATION_BATCH_DELAY)
    +
    +  private val podAllocationSize = conf.get(KUBERNETES_ALLOCATION_BATCH_SIZE)
    +
    +  private val allocatorRunnable = new Runnable {
    +
    +    // Maintains a map of executor id to count of checks performed to learn the loss
reason
    +    // for an executor.
    +    private val executorReasonCheckAttemptCounts = new mutable.HashMap[String, Int]
    +
    +    override def run(): Unit = {
    +      handleDisconnectedExecutors()
    +      val executorsToAllocate = mutable.Map[String, Pod]()
    +      val currentTotalRegisteredExecutors = totalRegisteredExecutors.get
    +      val currentTotalExpectedExecutors = totalExpectedExecutors.get
    +      val currentNodeToLocalTaskCount = getNodesWithLocalTaskCounts
    +      if (currentTotalRegisteredExecutors < runningExecutorsToPods.size) {
    +        logDebug("Waiting for pending executors before scaling")
    +      } else if (currentTotalExpectedExecutors <= runningExecutorsToPods.size) {
    +        logDebug("Maximum allowed executor limit reached. Not scaling up further.")
    +      } else {
    +        for (i <- 0 until math.min(
    +          currentTotalExpectedExecutors - runningExecutorsToPods.size, podAllocationSize))
{
    +          val executorId = EXECUTOR_ID_COUNTER.incrementAndGet().toString
    +          val executorPod = executorPodFactory.createExecutorPod(
    +            executorId,
    +            applicationId(),
    +            driverUrl,
    +            conf.getExecutorEnv,
    +            driverPod,
    +            currentNodeToLocalTaskCount)
    +          require(executorPod.getMetadata.getLabels.containsKey(SPARK_EXECUTOR_ID_LABEL),
    +            s"Illegal internal state for pod with name ${executorPod.getMetadata.getName}
- all" +
    +              s" executor pods must contain the label $SPARK_EXECUTOR_ID_LABEL.")
    +          val resolvedExecutorIdLabel = executorPod.getMetadata.getLabels.get(
    +            SPARK_EXECUTOR_ID_LABEL)
    +          require(resolvedExecutorIdLabel == executorId,
    +            s"Illegal internal state for pod with name ${executorPod.getMetadata.getName}
- all" +
    +              s" executor pods must map the label with key ${SPARK_EXECUTOR_ID_LABEL}
to the" +
    +              s" executor's ID. This label mapped instead to: $resolvedExecutorIdLabel.")
    +          executorsToAllocate(executorId) = executorPod
    +          logInfo(
    +            s"Requesting a new executor, total executors is now ${runningExecutorsToPods.size}")
    +        }
    +      }
    +      val allocatedExecutors = executorsToAllocate.mapValues { pod =>
    +        Utils.tryLog {
    +          kubernetesClient.pods().create(pod)
    +        }
    +      }
    +      RUNNING_EXECUTOR_PODS_LOCK.synchronized {
    +        allocatedExecutors.map {
    +          case (executorId, attemptedAllocatedExecutor) =>
    +            attemptedAllocatedExecutor.map { successfullyAllocatedExecutor =>
    +              runningExecutorsToPods.put(executorId, successfullyAllocatedExecutor)
    +            }
    +        }
    +      }
    +    }
    +
    +    def handleDisconnectedExecutors(): Unit = {
    +      // For each disconnected executor, synchronize with the loss reasons that may have
been found
    +      // by the executor pod watcher. If the loss reason was discovered by the watcher,
    +      // inform the parent class with removeExecutor.
    +      disconnectedPodsByExecutorIdPendingRemoval.asScala.foreach {
    +        case (executorId, executorPod) =>
    +          val knownExitReason = Option(podsWithKnownExitReasons.remove(
    +            executorPod.getMetadata.getName))
    +          knownExitReason.fold {
    +            removeExecutorOrIncrementLossReasonCheckCount(executorId)
    +          } { executorExited =>
    +            logWarning(s"Removing executor $executorId with loss reason " + executorExited.message)
    +            removeExecutor(executorId, executorExited)
    +            // We keep around executors that have exit conditions caused by the application.
This
    +            // allows them to be debugged later on. Otherwise, mark them as to be deleted
from the
    +            // the API server.
    +            if (executorExited.exitCausedByApp) {
    +              logInfo(s"Executor $executorId exited because of the application.")
    +              deleteExecutorFromDataStructures(executorId)
    +            } else {
    +              logInfo(s"Executor $executorId failed because of a framework error.")
    +              deleteExecutorFromClusterAndDataStructures(executorId)
    +            }
    +          }
    +      }
    +    }
    +
    +    def removeExecutorOrIncrementLossReasonCheckCount(executorId: String): Unit = {
    +      val reasonCheckCount = executorReasonCheckAttemptCounts.getOrElse(executorId, 0)
    +      if (reasonCheckCount >= MAX_EXECUTOR_LOST_REASON_CHECKS) {
    +        removeExecutor(executorId, SlaveLost("Executor lost for unknown reasons."))
    +        deleteExecutorFromClusterAndDataStructures(executorId)
    +      } else {
    +        executorReasonCheckAttemptCounts.put(executorId, reasonCheckCount + 1)
    +      }
    +    }
    +
    +    def deleteExecutorFromClusterAndDataStructures(executorId: String): Unit = {
    +      deleteExecutorFromDataStructures(executorId)
    +        .foreach(pod => kubernetesClient.pods().delete(pod))
    +    }
    +
    +    def deleteExecutorFromDataStructures(executorId: String): Option[Pod] = {
    +      disconnectedPodsByExecutorIdPendingRemoval.remove(executorId)
    +      executorReasonCheckAttemptCounts -= executorId
    +      podsWithKnownExitReasons.remove(executorId)
    +      RUNNING_EXECUTOR_PODS_LOCK.synchronized {
    +        runningExecutorsToPods.remove(executorId).orElse {
    +          logWarning(s"Unable to remove pod for unknown executor $executorId")
    +          None
    +        }
    +      }
    +    }
    +  }
    +
    +  override def sufficientResourcesRegistered(): Boolean = {
    +    totalRegisteredExecutors.get() >= initialExecutors * minRegisteredRatio
    +  }
    +
    +  override def start(): Unit = {
    +    super.start()
    +    executorWatchResource.set(
    +      kubernetesClient
    +        .pods()
    +        .withLabel(SPARK_APP_ID_LABEL, applicationId())
    +        .watch(new ExecutorPodsWatcher()))
    +
    +    allocatorExecutor.scheduleWithFixedDelay(
    +      allocatorRunnable, 0L, podAllocationInterval, TimeUnit.SECONDS)
    +
    +    if (!Utils.isDynamicAllocationEnabled(conf)) {
    +      doRequestTotalExecutors(initialExecutors)
    +    }
    +  }
    +
    +  override def stop(): Unit = {
    +    // stop allocation of new resources and caches.
    +    allocatorExecutor.shutdown()
    +
    +    // send stop message to executors so they shut down cleanly
    +    super.stop()
    +
    +    // then delete the executor pods
    +    Utils.tryLogNonFatalError {
    +      val executorPodsToDelete = RUNNING_EXECUTOR_PODS_LOCK.synchronized {
    +        val runningExecutorPodsCopy = Seq(runningExecutorsToPods.values.toSeq: _*)
    +        runningExecutorsToPods.clear()
    +        runningExecutorPodsCopy
    +      }
    +      kubernetesClient.pods().delete(executorPodsToDelete: _*)
    +      executorPodsByIPs.clear()
    +      val resource = executorWatchResource.getAndSet(null)
    +      if (resource != null) {
    +        resource.close()
    +      }
    +    }
    +    Utils.tryLogNonFatalError {
    +      logInfo("Closing kubernetes client")
    +      kubernetesClient.close()
    +    }
    +  }
    +
    +  /**
    +   * @return A map of K8s cluster nodes to the number of tasks that could benefit from
data
    +   *         locality if an executor launches on the cluster node.
    +   */
    +  private def getNodesWithLocalTaskCounts() : Map[String, Int] = {
    +    val nodeToLocalTaskCount = mutable.Map[String, Int]() ++
    +      synchronized {
    +        hostToLocalTaskCount
    +      }
    +    for (pod <- executorPodsByIPs.values().asScala) {
    +      // Remove cluster nodes that are running our executors already.
    +      // TODO: This prefers spreading out executors across nodes. In case users want
    +      // consolidating executors on fewer nodes, introduce a flag. See the spark.deploy.spreadOut
    +      // flag that Spark standalone has: https://spark.apache.org/docs/latest/spark-standalone.html
    +      nodeToLocalTaskCount.remove(pod.getSpec.getNodeName).nonEmpty ||
    +        nodeToLocalTaskCount.remove(pod.getStatus.getHostIP).nonEmpty ||
    +        nodeToLocalTaskCount.remove(
    +          InetAddress.getByName(pod.getStatus.getHostIP).getCanonicalHostName).nonEmpty
    +    }
    +    nodeToLocalTaskCount.toMap[String, Int]
    +  }
    +
    +  override def doRequestTotalExecutors(requestedTotal: Int): Future[Boolean] = Future[Boolean]
{
    +    totalExpectedExecutors.set(requestedTotal)
    +    true
    +  }
    +
    +  override def doKillExecutors(executorIds: Seq[String]): Future[Boolean] = Future[Boolean]
{
    +    val podsToDelete = mutable.Buffer[Pod]()
    +    RUNNING_EXECUTOR_PODS_LOCK.synchronized {
    +      for (executor <- executorIds) {
    +        val maybeRemovedExecutor = runningExecutorsToPods.remove(executor)
    +        maybeRemovedExecutor.foreach { executorPod =>
    +          disconnectedPodsByExecutorIdPendingRemoval.put(executor, executorPod)
    +          podsToDelete += executorPod
    +        }
    +        if (maybeRemovedExecutor.isEmpty) {
    +          logWarning(s"Unable to remove pod for unknown executor $executor")
    +        }
    +      }
    +    }
    +    kubernetesClient.pods().delete(podsToDelete: _*)
    +    true
    +  }
    +
    +  private class ExecutorPodsWatcher extends Watcher[Pod] {
    +
    +    private val DEFAULT_CONTAINER_FAILURE_EXIT_STATUS = -1
    +
    +    override def eventReceived(action: Action, pod: Pod): Unit = {
    +      action match {
    +        case Action.MODIFIED if (pod.getStatus.getPhase == "Running"
    +          && pod.getMetadata.getDeletionTimestamp == null) =>
    --- End diff --
    
    Indent one extra level.


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