Github user mccheah commented on a diff in the pull request:
https://github.com/apache/spark/pull/19468#discussion_r147016564
--- Diff:
resource-managers/kubernetes/core/src/main/scala/org/apache/spark/scheduler/cluster/k8s/KubernetesClusterSchedulerBackend.scala
---
@@ -0,0 +1,440 @@
+/*
+ * 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 scala.collection.JavaConverters._
+import scala.collection.mutable
+import scala.concurrent.{ExecutionContext, Future}
+
+import io.fabric8.kubernetes.api.model._
+import io.fabric8.kubernetes.client.{KubernetesClient,
KubernetesClientException, Watcher}
+import io.fabric8.kubernetes.client.Watcher.Action
+
+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
+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
+ // Indexed by executor IDs and guarded by RUNNING_EXECUTOR_PODS_LOCK.
+ private val runningExecutorsToPods = new mutable.HashMap[String, Pod]
+ // Indexed by executor pod names and guarded by
RUNNING_EXECUTOR_PODS_LOCK.
+ private val runningPodsToExecutors = new mutable.HashMap[String, String]
+ 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 = try {
+ kubernetesClient.pods()
+ .inNamespace(kubernetesNamespace)
+ .withName(kubernetesDriverPodName)
+ .get()
+ } catch {
+ case throwable: Throwable =>
+ logError(s"Executor cannot find driver pod.", throwable)
+ throw new SparkException(s"Executor cannot find driver pod",
throwable)
+ }
+
+ 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 = getInitialTargetExecutorNumber()
+
+ private val podAllocationInterval =
conf.get(KUBERNETES_ALLOCATION_BATCH_DELAY)
+ require(podAllocationInterval > 0, s"Allocation batch delay " +
+ s"${KUBERNETES_ALLOCATION_BATCH_DELAY} " +
+ s"is ${podAllocationInterval}, should be a positive integer")
+
+ private val podAllocationSize =
conf.get(KUBERNETES_ALLOCATION_BATCH_SIZE)
+ require(podAllocationSize > 0, s"Allocation batch size " +
+ s"${KUBERNETES_ALLOCATION_BATCH_SIZE} " +
+ s"is ${podAllocationSize}, should be a positive integer")
+
+ 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()
+ RUNNING_EXECUTOR_PODS_LOCK.synchronized {
+ if (totalRegisteredExecutors.get() < runningExecutorsToPods.size) {
+ logDebug("Waiting for pending executors before scaling")
+ } else if (totalExpectedExecutors.get() <=
runningExecutorsToPods.size) {
+ logDebug("Maximum allowed executor limit reached. Not scaling up
further.")
+ } else {
+ val nodeToLocalTaskCount = getNodesWithLocalTaskCounts
+ for (i <- 0 until math.min(
+ totalExpectedExecutors.get - runningExecutorsToPods.size,
podAllocationSize)) {
+ val (executorId, pod) =
allocateNewExecutorPod(nodeToLocalTaskCount)
+ runningExecutorsToPods.put(executorId, pod)
+ runningPodsToExecutors.put(pod.getMetadata.getName, executorId)
+ logInfo(
+ s"Requesting a new executor, total executors is now
${runningExecutorsToPods.size}")
+ }
+ }
+ }
+ }
+
+ 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.keys().asScala.foreach {
case (executorId) =>
+ val executorPod =
disconnectedPodsByExecutorIdPendingRemoval.get(executorId)
+ val knownExitReason = Option(podsWithKnownExitReasons.remove(
+ executorPod.getMetadata.getName))
+ knownExitReason.fold {
+ removeExecutorOrIncrementLossReasonCheckCount(executorId)
+ } { executorExited =>
+ logDebug(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) {
+ 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 = {
+ disconnectedPodsByExecutorIdPendingRemoval.remove(executorId)
+ executorReasonCheckAttemptCounts -= executorId
+ RUNNING_EXECUTOR_PODS_LOCK.synchronized {
+ runningExecutorsToPods.remove(executorId).map { pod =>
+ kubernetesClient.pods().delete(pod)
--- End diff --
By asynchronous I mean that after the HTTP request is sent, the response
comes back before the Kubernetes master has actually done the work of tearing
the pod down.
All calls are synchronous with respect to the HTTP call, but the work done
in response to HTTP requests are themselves done asynchronously. So we could
still bottleneck here if e.g. there's a connection timeout to the Kubernetes
API. It might not be a significant difference in this case because a breakdown
in communication with the API server is going to cause all sorts of problems
outside of locked code in the first place.
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