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/*
* 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
import java.util.concurrent.{ScheduledFuture, TimeUnit}
import scala.collection.mutable
import scala.concurrent.Future
import org.apache.spark.internal.Logging
import org.apache.spark.rpc.{RpcCallContext, RpcEnv, ThreadSafeRpcEndpoint}
import org.apache.spark.scheduler._
import org.apache.spark.storage.BlockManagerId
import org.apache.spark.util._
/**
* A heartbeat from executors to the driver. This is a shared message used by several internal
* components to convey liveness or execution information for in-progress tasks. It will also
* expire the hosts that have not heartbeated for more than spark.network.timeout.
* spark.executor.heartbeatInterval should be significantly less than spark.network.timeout.
*/
private[spark] case class Heartbeat(
executorId: String,
accumUpdates: Array[(Long, Seq[AccumulatorV2[_, _]])], // taskId -> accumulator updates
blockManagerId: BlockManagerId)
/**
* An event that SparkContext uses to notify HeartbeatReceiver that SparkContext.taskScheduler is
* created.
*/
private[spark] case object TaskSchedulerIsSet
private[spark] case object ExpireDeadHosts
private case class ExecutorRegistered(executorId: String)
private case class ExecutorRemoved(executorId: String)
private[spark] case class HeartbeatResponse(reregisterBlockManager: Boolean)
/**
* Lives in the driver to receive heartbeats from executors..
*/
private[spark] class HeartbeatReceiver(sc: SparkContext, clock: Clock)
extends SparkListener with ThreadSafeRpcEndpoint with Logging {
def this(sc: SparkContext) {
this(sc, new SystemClock)
}
sc.listenerBus.addToManagementQueue(this)
override val rpcEnv: RpcEnv = sc.env.rpcEnv
private[spark] var scheduler: TaskScheduler = null
// executor ID -> timestamp of when the last heartbeat from this executor was received
private val executorLastSeen = new mutable.HashMap[String, Long]
// "spark.network.timeout" uses "seconds", while `spark.storage.blockManagerSlaveTimeoutMs` uses
// "milliseconds"
private val executorTimeoutMs =
sc.conf.getTimeAsMs("spark.storage.blockManagerSlaveTimeoutMs",
s"${sc.conf.getTimeAsSeconds("spark.network.timeout", "120s")}s")
// "spark.network.timeoutInterval" uses "seconds", while
// "spark.storage.blockManagerTimeoutIntervalMs" uses "milliseconds"
private val timeoutIntervalMs =
sc.conf.getTimeAsMs("spark.storage.blockManagerTimeoutIntervalMs", "60s")
private val checkTimeoutIntervalMs =
sc.conf.getTimeAsSeconds("spark.network.timeoutInterval", s"${timeoutIntervalMs}ms") * 1000
private var timeoutCheckingTask: ScheduledFuture[_] = null
// "eventLoopThread" is used to run some pretty fast actions. The actions running in it should not
// block the thread for a long time.
private val eventLoopThread =
ThreadUtils.newDaemonSingleThreadScheduledExecutor("heartbeat-receiver-event-loop-thread")
private val killExecutorThread = ThreadUtils.newDaemonSingleThreadExecutor("kill-executor-thread")
override def onStart(): Unit = {
timeoutCheckingTask = eventLoopThread.scheduleAtFixedRate(new Runnable {
override def run(): Unit = Utils.tryLogNonFatalError {
Option(self).foreach(_.ask[Boolean](ExpireDeadHosts))
}
}, 0, checkTimeoutIntervalMs, TimeUnit.MILLISECONDS)
}
override def receiveAndReply(context: RpcCallContext): PartialFunction[Any, Unit] = {
// Messages sent and received locally
case ExecutorRegistered(executorId) =>
executorLastSeen(executorId) = clock.getTimeMillis()
context.reply(true)
case ExecutorRemoved(executorId) =>
executorLastSeen.remove(executorId)
context.reply(true)
case TaskSchedulerIsSet =>
scheduler = sc.taskScheduler
context.reply(true)
case ExpireDeadHosts =>
expireDeadHosts()
context.reply(true)
// Messages received from executors
case heartbeat @ Heartbeat(executorId, accumUpdates, blockManagerId) =>
if (scheduler != null) {
if (executorLastSeen.contains(executorId)) {
executorLastSeen(executorId) = clock.getTimeMillis()
eventLoopThread.submit(new Runnable {
override def run(): Unit = Utils.tryLogNonFatalError {
val unknownExecutor = !scheduler.executorHeartbeatReceived(
executorId, accumUpdates, blockManagerId)
val response = HeartbeatResponse(reregisterBlockManager = unknownExecutor)
context.reply(response)
}
})
} else {
// This may happen if we get an executor's in-flight heartbeat immediately
// after we just removed it. It's not really an error condition so we should
// not log warning here. Otherwise there may be a lot of noise especially if
// we explicitly remove executors (SPARK-4134).
logDebug(s"Received heartbeat from unknown executor $executorId")
context.reply(HeartbeatResponse(reregisterBlockManager = true))
}
} else {
// Because Executor will sleep several seconds before sending the first "Heartbeat", this
// case rarely happens. However, if it really happens, log it and ask the executor to
// register itself again.
logWarning(s"Dropping $heartbeat because TaskScheduler is not ready yet")
context.reply(HeartbeatResponse(reregisterBlockManager = true))
}
}
/**
* Send ExecutorRegistered to the event loop to add a new executor. Only for test.
*
* @return if HeartbeatReceiver is stopped, return None. Otherwise, return a Some(Future) that
* indicate if this operation is successful.
*/
def addExecutor(executorId: String): Option[Future[Boolean]] = {
Option(self).map(_.ask[Boolean](ExecutorRegistered(executorId)))
}
/**
* If the heartbeat receiver is not stopped, notify it of executor registrations.
*/
override def onExecutorAdded(executorAdded: SparkListenerExecutorAdded): Unit = {
addExecutor(executorAdded.executorId)
}
/**
* Send ExecutorRemoved to the event loop to remove an executor. Only for test.
*
* @return if HeartbeatReceiver is stopped, return None. Otherwise, return a Some(Future) that
* indicate if this operation is successful.
*/
def removeExecutor(executorId: String): Option[Future[Boolean]] = {
Option(self).map(_.ask[Boolean](ExecutorRemoved(executorId)))
}
/**
* If the heartbeat receiver is not stopped, notify it of executor removals so it doesn't
* log superfluous errors.
*
* Note that we must do this after the executor is actually removed to guard against the
* following race condition: if we remove an executor's metadata from our data structure
* prematurely, we may get an in-flight heartbeat from the executor before the executor is
* actually removed, in which case we will still mark the executor as a dead host later
* and expire it with loud error messages.
*/
override def onExecutorRemoved(executorRemoved: SparkListenerExecutorRemoved): Unit = {
removeExecutor(executorRemoved.executorId)
}
private def expireDeadHosts(): Unit = {
logTrace("Checking for hosts with no recent heartbeats in HeartbeatReceiver.")
val now = clock.getTimeMillis()
for ((executorId, lastSeenMs) <- executorLastSeen) {
if (now - lastSeenMs > executorTimeoutMs) {
logWarning(s"Removing executor $executorId with no recent heartbeats: " +
s"${now - lastSeenMs} ms exceeds timeout $executorTimeoutMs ms")
scheduler.executorLost(executorId, SlaveLost("Executor heartbeat " +
s"timed out after ${now - lastSeenMs} ms"))
// Asynchronously kill the executor to avoid blocking the current thread
killExecutorThread.submit(new Runnable {
override def run(): Unit = Utils.tryLogNonFatalError {
// Note: we want to get an executor back after expiring this one,
// so do not simply call `sc.killExecutor` here (SPARK-8119)
sc.killAndReplaceExecutor(executorId)
}
})
executorLastSeen.remove(executorId)
}
}
}
override def onStop(): Unit = {
if (timeoutCheckingTask != null) {
timeoutCheckingTask.cancel(true)
}
eventLoopThread.shutdownNow()
killExecutorThread.shutdownNow()
}
}
private[spark] object HeartbeatReceiver {
val ENDPOINT_NAME = "HeartbeatReceiver"
}
