spark HealthTracker 源码
spark HealthTracker 代码
文件路径：/core/src/main/scala/org/apache/spark/scheduler/HealthTracker.scala
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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,
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* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.spark.scheduler
import java.util.concurrent.atomic.AtomicReference
import scala.collection.mutable.{ArrayBuffer, HashMap, HashSet}
import org.apache.spark.{ExecutorAllocationClient, SparkConf, SparkContext}
import org.apache.spark.internal.Logging
import org.apache.spark.internal.config
import org.apache.spark.util.{Clock, SystemClock, Utils}
/**
* HealthTracker is designed to track problematic executors and nodes. It supports excluding
* executors and nodes across an entire application (with a periodic expiry). TaskSetManagers add
* additional logic for exclusion of executors and nodes for individual tasks and stages which
* works in concert with the logic here.
*
* The tracker needs to deal with a variety of workloads, e.g.:
*
* * bad user code -- this may lead to many task failures, but that should not count against
* individual executors
* * many small stages -- this may prevent a bad executor for having many failures within one
* stage, but still many failures over the entire application
* * "flaky" executors -- they don't fail every task, but are still faulty enough to merit
* excluding
* * missing shuffle files -- may trigger fetch failures on healthy executors.
*
* See the design doc on SPARK-8425 for a more in-depth discussion. Note SPARK-32037 renamed
* the feature.
*
* THREADING: As with most helpers of TaskSchedulerImpl, this is not thread-safe. Though it is
* called by multiple threads, callers must already have a lock on the TaskSchedulerImpl. The
* one exception is [[excludedNodeList()]], which can be called without holding a lock.
*/
private[scheduler] class HealthTracker (
private val listenerBus: LiveListenerBus,
conf: SparkConf,
allocationClient: Option[ExecutorAllocationClient],
clock: Clock = new SystemClock()) extends Logging {
def this(sc: SparkContext, allocationClient: Option[ExecutorAllocationClient]) = {
this(sc.listenerBus, sc.conf, allocationClient)
}
HealthTracker.validateExcludeOnFailureConfs(conf)
private val MAX_FAILURES_PER_EXEC = conf.get(config.MAX_FAILURES_PER_EXEC)
private val MAX_FAILED_EXEC_PER_NODE = conf.get(config.MAX_FAILED_EXEC_PER_NODE)
val EXCLUDE_ON_FAILURE_TIMEOUT_MILLIS = HealthTracker.getExludeOnFailureTimeout(conf)
private val EXCLUDE_FETCH_FAILURE_ENABLED =
conf.get(config.EXCLUDE_ON_FAILURE_FETCH_FAILURE_ENABLED)
private val EXCLUDE_ON_FAILURE_DECOMMISSION_ENABLED =
conf.get(config.EXCLUDE_ON_FAILURE_DECOMMISSION_ENABLED)
/**
* A map from executorId to information on task failures. Tracks the time of each task failure,
* so that we can avoid excluding executors due to failures that are very far apart. We do not
* actively remove from this as soon as tasks hit their timeouts, to avoid the time it would take
* to do so. But it will not grow too large, because as soon as an executor gets too many
* failures, we exclude the executor and remove its entry here.
*/
private val executorIdToFailureList = new HashMap[String, ExecutorFailureList]()
val executorIdToExcludedStatus = new HashMap[String, ExcludedExecutor]()
val nodeIdToExcludedExpiryTime = new HashMap[String, Long]()
/**
* An immutable copy of the set of nodes that are currently excluded. Kept in an
* AtomicReference to make [[excludedNodeList()]] thread-safe.
*/
private val _excludedNodeList = new AtomicReference[Set[String]](Set())
/**
* Time when the next excluded node will expire. Used as a shortcut to
* avoid iterating over all entries in the excludedNodeList when none will have expired.
*/
var nextExpiryTime: Long = Long.MaxValue
/**
* Mapping from nodes to all of the executors that have been excluded on that node. We do *not*
* remove from this when executors are removed from spark, so we can track when we get multiple
* successive excluded executors on one node. Nonetheless, it will not grow too large because
* there cannot be many excluded executors on one node, before we stop requesting more
* executors on that node, and we clean up the list of exluded executors once an executor has
* been excluded for EXCLUDE_ON_FAILURE_TIMEOUT_MILLIS.
*/
val nodeToExcludedExecs = new HashMap[String, HashSet[String]]()
/**
* Include executors and nodes that have been excluded for at least
* EXCLUDE_ON_FAILURE_TIMEOUT_MILLIS
*/
def applyExcludeOnFailureTimeout(): Unit = {
val now = clock.getTimeMillis()
// quickly check if we've got anything to expire that is excluded -- if not,
// avoid doing any work
if (now > nextExpiryTime) {
// Apply the timeout to excluded nodes and executors
val execsToInclude = executorIdToExcludedStatus.filter(_._2.expiryTime < now).keys
if (execsToInclude.nonEmpty) {
// Include any executors that have been exluded longer than the excludeOnFailure timeout.
logInfo(s"Removing executors $execsToInclude from exclude list because the " +
s"the executors have reached the timed out")
execsToInclude.foreach { exec =>
val status = executorIdToExcludedStatus.remove(exec).get
val failedExecsOnNode = nodeToExcludedExecs(status.node)
// post both to keep backwards compatibility
listenerBus.post(SparkListenerExecutorUnblacklisted(now, exec))
listenerBus.post(SparkListenerExecutorUnexcluded(now, exec))
failedExecsOnNode.remove(exec)
if (failedExecsOnNode.isEmpty) {
nodeToExcludedExecs.remove(status.node)
}
}
}
val nodesToInclude = nodeIdToExcludedExpiryTime.filter(_._2 < now).keys
if (nodesToInclude.nonEmpty) {
// Include any nodes that have been excluded longer than the excludeOnFailure timeout.
logInfo(s"Removing nodes $nodesToInclude from exclude list because the " +
s"nodes have reached has timed out")
nodesToInclude.foreach { node =>
nodeIdToExcludedExpiryTime.remove(node)
// post both to keep backwards compatibility
listenerBus.post(SparkListenerNodeUnblacklisted(now, node))
listenerBus.post(SparkListenerNodeUnexcluded(now, node))
}
_excludedNodeList.set(nodeIdToExcludedExpiryTime.keySet.toSet)
}
updateNextExpiryTime()
}
}
private def updateNextExpiryTime(): Unit = {
val execMinExpiry = if (executorIdToExcludedStatus.nonEmpty) {
executorIdToExcludedStatus.map{_._2.expiryTime}.min
} else {
Long.MaxValue
}
val nodeMinExpiry = if (nodeIdToExcludedExpiryTime.nonEmpty) {
nodeIdToExcludedExpiryTime.values.min
} else {
Long.MaxValue
}
nextExpiryTime = math.min(execMinExpiry, nodeMinExpiry)
}
private def killExecutor(exec: String, msg: String): Unit = {
val fullMsg = if (EXCLUDE_ON_FAILURE_DECOMMISSION_ENABLED) {
s"${msg} (actually decommissioning)"
} else {
msg
}
allocationClient match {
case Some(a) =>
logInfo(fullMsg)
if (EXCLUDE_ON_FAILURE_DECOMMISSION_ENABLED) {
a.decommissionExecutor(exec, ExecutorDecommissionInfo(fullMsg),
adjustTargetNumExecutors = false)
} else {
a.killExecutors(Seq(exec), adjustTargetNumExecutors = false, countFailures = false,
force = true)
}
case None =>
logInfo(s"Not attempting to kill excluded executor id $exec " +
s"since allocation client is not defined.")
}
}
private def killExcludedExecutor(exec: String): Unit = {
if (conf.get(config.EXCLUDE_ON_FAILURE_KILL_ENABLED)) {
killExecutor(exec, s"Killing excluded executor id $exec since " +
s"${config.EXCLUDE_ON_FAILURE_KILL_ENABLED.key} is set.")
}
}
private[scheduler] def killExcludedIdleExecutor(exec: String): Unit = {
killExecutor(exec,
s"Killing excluded idle executor id $exec because of task unschedulability and trying " +
"to acquire a new executor.")
}
private def killExecutorsOnExcludedNode(node: String): Unit = {
if (conf.get(config.EXCLUDE_ON_FAILURE_KILL_ENABLED)) {
allocationClient match {
case Some(a) =>
if (EXCLUDE_ON_FAILURE_DECOMMISSION_ENABLED) {
logInfo(s"Decommissioning all executors on excluded host $node " +
s"since ${config.EXCLUDE_ON_FAILURE_KILL_ENABLED.key} is set.")
if (!a.decommissionExecutorsOnHost(node)) {
logError(s"Decommissioning executors on $node failed.")
}
} else {
logInfo(s"Killing all executors on excluded host $node " +
s"since ${config.EXCLUDE_ON_FAILURE_KILL_ENABLED.key} is set.")
if (!a.killExecutorsOnHost(node)) {
logError(s"Killing executors on node $node failed.")
}
}
case None =>
logWarning(s"Not attempting to kill executors on excluded host $node " +
s"since allocation client is not defined.")
}
}
}
def updateExcludedForFetchFailure(host: String, exec: String): Unit = {
if (EXCLUDE_FETCH_FAILURE_ENABLED) {
// If we exclude on fetch failures, we are implicitly saying that we believe the failure is
// non-transient, and can't be recovered from (even if this is the first fetch failure,
// stage is retried after just one failure, so we don't always get a chance to collect
// multiple fetch failures).
// If the external shuffle-service is on, then every other executor on this node would
// be suffering from the same issue, so we should exclude (and potentially kill) all
// of them immediately.
val now = clock.getTimeMillis()
val expiryTimeForNewExcludes = now + EXCLUDE_ON_FAILURE_TIMEOUT_MILLIS
if (conf.get(config.SHUFFLE_SERVICE_ENABLED)) {
if (!nodeIdToExcludedExpiryTime.contains(host)) {
logInfo(s"excluding node $host due to fetch failure of external shuffle service")
nodeIdToExcludedExpiryTime.put(host, expiryTimeForNewExcludes)
// post both to keep backwards compatibility
listenerBus.post(SparkListenerNodeBlacklisted(now, host, 1))
listenerBus.post(SparkListenerNodeExcluded(now, host, 1))
_excludedNodeList.set(nodeIdToExcludedExpiryTime.keySet.toSet)
killExecutorsOnExcludedNode(host)
updateNextExpiryTime()
}
} else if (!executorIdToExcludedStatus.contains(exec)) {
logInfo(s"Excluding executor $exec due to fetch failure")
executorIdToExcludedStatus.put(exec, ExcludedExecutor(host, expiryTimeForNewExcludes))
// We hardcoded number of failure tasks to 1 for fetch failure, because there's no
// reattempt for such failure.
// post both to keep backwards compatibility
listenerBus.post(SparkListenerExecutorBlacklisted(now, exec, 1))
listenerBus.post(SparkListenerExecutorExcluded(now, exec, 1))
updateNextExpiryTime()
killExcludedExecutor(exec)
val excludedExecsOnNode = nodeToExcludedExecs.getOrElseUpdate(host, HashSet[String]())
excludedExecsOnNode += exec
}
}
}
def updateExcludedForSuccessfulTaskSet(
stageId: Int,
stageAttemptId: Int,
failuresByExec: HashMap[String, ExecutorFailuresInTaskSet]): Unit = {
// if any tasks failed, we count them towards the overall failure count for the executor at
// this point.
val now = clock.getTimeMillis()
failuresByExec.foreach { case (exec, failuresInTaskSet) =>
val appFailuresOnExecutor =
executorIdToFailureList.getOrElseUpdate(exec, new ExecutorFailureList)
appFailuresOnExecutor.addFailures(stageId, stageAttemptId, failuresInTaskSet)
appFailuresOnExecutor.dropFailuresWithTimeoutBefore(now)
val newTotal = appFailuresOnExecutor.numUniqueTaskFailures
val expiryTimeForNewExcludes = now + EXCLUDE_ON_FAILURE_TIMEOUT_MILLIS
// If this pushes the total number of failures over the threshold, exclude the executor.
// If its already excluded, we avoid "re-excluding" (which can happen if there were
// other tasks already running in another taskset when it got excluded), because it makes
// some of the logic around expiry times a little more confusing. But it also wouldn't be a
// problem to re-exclude, with a later expiry time.
if (newTotal >= MAX_FAILURES_PER_EXEC && !executorIdToExcludedStatus.contains(exec)) {
logInfo(s"Excluding executor id: $exec because it has $newTotal" +
s" task failures in successful task sets")
val node = failuresInTaskSet.node
executorIdToExcludedStatus.put(exec, ExcludedExecutor(node, expiryTimeForNewExcludes))
// post both to keep backwards compatibility
listenerBus.post(SparkListenerExecutorBlacklisted(now, exec, newTotal))
listenerBus.post(SparkListenerExecutorExcluded(now, exec, newTotal))
executorIdToFailureList.remove(exec)
updateNextExpiryTime()
killExcludedExecutor(exec)
// In addition to excluding the executor, we also update the data for failures on the
// node, and potentially exclude the entire node as well.
val excludedExecsOnNode = nodeToExcludedExecs.getOrElseUpdate(node, HashSet[String]())
excludedExecsOnNode += exec
// If the node is already excluded, we avoid adding it again with a later expiry
// time.
if (excludedExecsOnNode.size >= MAX_FAILED_EXEC_PER_NODE &&
!nodeIdToExcludedExpiryTime.contains(node)) {
logInfo(s"Excluding node $node because it has ${excludedExecsOnNode.size} " +
s"executors excluded: ${excludedExecsOnNode}")
nodeIdToExcludedExpiryTime.put(node, expiryTimeForNewExcludes)
// post both to keep backwards compatibility
listenerBus.post(SparkListenerNodeBlacklisted(now, node, excludedExecsOnNode.size))
listenerBus.post(SparkListenerNodeExcluded(now, node, excludedExecsOnNode.size))
_excludedNodeList.set(nodeIdToExcludedExpiryTime.keySet.toSet)
killExecutorsOnExcludedNode(node)
}
}
}
}
def isExecutorExcluded(executorId: String): Boolean = {
executorIdToExcludedStatus.contains(executorId)
}
/**
* Get the full set of nodes that are excluded. Unlike other methods in this class, this *IS*
* thread-safe -- no lock required on a taskScheduler.
*/
def excludedNodeList(): Set[String] = {
_excludedNodeList.get()
}
def isNodeExcluded(node: String): Boolean = {
nodeIdToExcludedExpiryTime.contains(node)
}
def handleRemovedExecutor(executorId: String): Unit = {
// We intentionally do not clean up executors that are already excluded in
// nodeToExcludedExecs, so that if another executor on the same node gets excluded, we can
// exclude the entire node. We also can't clean up executorIdToExcludedStatus, so we can
// eventually remove the executor after the timeout. Despite not clearing those structures
// here, we don't expect they will grow too big since you won't get too many executors on one
// node, and the timeout will clear it up periodically in any case.
executorIdToFailureList -= executorId
}
/**
* Tracks all failures for one executor (that have not passed the timeout).
*
* In general we actually expect this to be extremely small, since it won't contain more than the
* maximum number of task failures before an executor is failed (default 2).
*/
private[scheduler] final class ExecutorFailureList extends Logging {
private case class TaskId(stage: Int, stageAttempt: Int, taskIndex: Int)
/**
* All failures on this executor in successful task sets.
*/
private var failuresAndExpiryTimes = ArrayBuffer[(TaskId, Long)]()
/**
* As an optimization, we track the min expiry time over all entries in failuresAndExpiryTimes
* so its quick to tell if there are any failures with expiry before the current time.
*/
private var minExpiryTime = Long.MaxValue
def addFailures(
stage: Int,
stageAttempt: Int,
failuresInTaskSet: ExecutorFailuresInTaskSet): Unit = {
failuresInTaskSet.taskToFailureCountAndFailureTime.foreach {
case (taskIdx, (_, failureTime)) =>
val expiryTime = failureTime + EXCLUDE_ON_FAILURE_TIMEOUT_MILLIS
failuresAndExpiryTimes += ((TaskId(stage, stageAttempt, taskIdx), expiryTime))
if (expiryTime < minExpiryTime) {
minExpiryTime = expiryTime
}
}
}
/**
* The number of unique tasks that failed on this executor. Only counts failures within the
* timeout, and in successful tasksets.
*/
def numUniqueTaskFailures: Int = failuresAndExpiryTimes.size
def isEmpty: Boolean = failuresAndExpiryTimes.isEmpty
/**
* Apply the timeout to individual tasks. This is to prevent one-off failures that are very
* spread out in time (and likely have nothing to do with problems on the executor) from
* triggering exlusion. However, note that we do *not* remove executors and nodes from
* being excluded as we expire individual task failures -- each have their own timeout. E.g.,
* suppose:
* * timeout = 10, maxFailuresPerExec = 2
* * Task 1 fails on exec 1 at time 0
* * Task 2 fails on exec 1 at time 5
* --> exec 1 is excluded from time 5 - 15.
* This is to simplify the implementation, as well as keep the behavior easier to understand
* for the end user.
*/
def dropFailuresWithTimeoutBefore(dropBefore: Long): Unit = {
if (minExpiryTime < dropBefore) {
var newMinExpiry = Long.MaxValue
val newFailures = new ArrayBuffer[(TaskId, Long)]
failuresAndExpiryTimes.foreach { case (task, expiryTime) =>
if (expiryTime >= dropBefore) {
newFailures += ((task, expiryTime))
if (expiryTime < newMinExpiry) {
newMinExpiry = expiryTime
}
}
}
failuresAndExpiryTimes = newFailures
minExpiryTime = newMinExpiry
}
}
override def toString(): String = {
s"failures = $failuresAndExpiryTimes"
}
}
}
private[spark] object HealthTracker extends Logging {
private val DEFAULT_TIMEOUT = "1h"
/**
* Returns true if the excludeOnFailure is enabled, based on checking the configuration
* in the following order:
* 1. Is it specifically enabled or disabled?
* 2. Is it enabled via the legacy timeout conf?
* 3. Default is off
*/
def isExcludeOnFailureEnabled(conf: SparkConf): Boolean = {
conf.get(config.EXCLUDE_ON_FAILURE_ENABLED) match {
case Some(enabled) =>
enabled
case None =>
// if they've got a non-zero setting for the legacy conf, always enable it,
// otherwise, use the default.
val legacyKey = config.EXCLUDE_ON_FAILURE_LEGACY_TIMEOUT_CONF.key
conf.get(config.EXCLUDE_ON_FAILURE_LEGACY_TIMEOUT_CONF).exists { legacyTimeout =>
if (legacyTimeout == 0) {
logWarning(s"Turning off excludeOnFailure due to legacy configuration: $legacyKey == 0")
false
} else {
logWarning(s"Turning on excludeOnFailure due to legacy configuration: $legacyKey > 0")
true
}
}
}
}
def getExludeOnFailureTimeout(conf: SparkConf): Long = {
conf.get(config.EXCLUDE_ON_FAILURE_TIMEOUT_CONF).getOrElse {
conf.get(config.EXCLUDE_ON_FAILURE_LEGACY_TIMEOUT_CONF).getOrElse {
Utils.timeStringAsMs(DEFAULT_TIMEOUT)
}
}
}
/**
* Verify that exclude on failure configurations are consistent; if not, throw an exception.
* Should only be called if excludeOnFailure is enabled.
*
* The configuration is expected to adhere to a few invariants. Default values
* follow these rules of course, but users may unwittingly change one configuration
* without making the corresponding adjustment elsewhere. This ensures we fail-fast when
* there are such misconfigurations.
*/
def validateExcludeOnFailureConfs(conf: SparkConf): Unit = {
def mustBePos(k: String, v: String): Unit = {
throw new IllegalArgumentException(s"$k was $v, but must be > 0.")
}
Seq(
config.MAX_TASK_ATTEMPTS_PER_EXECUTOR,
config.MAX_TASK_ATTEMPTS_PER_NODE,
config.MAX_FAILURES_PER_EXEC_STAGE,
config.MAX_FAILED_EXEC_PER_NODE_STAGE,
config.MAX_FAILURES_PER_EXEC,
config.MAX_FAILED_EXEC_PER_NODE
).foreach { config =>
val v = conf.get(config)
if (v <= 0) {
mustBePos(config.key, v.toString)
}
}
val timeout = getExludeOnFailureTimeout(conf)
if (timeout <= 0) {
// first, figure out where the timeout came from, to include the right conf in the message.
conf.get(config.EXCLUDE_ON_FAILURE_TIMEOUT_CONF) match {
case Some(t) =>
mustBePos(config.EXCLUDE_ON_FAILURE_TIMEOUT_CONF.key, timeout.toString)
case None =>
mustBePos(config.EXCLUDE_ON_FAILURE_LEGACY_TIMEOUT_CONF.key, timeout.toString)
}
}
val maxTaskFailures = conf.get(config.TASK_MAX_FAILURES)
val maxNodeAttempts = conf.get(config.MAX_TASK_ATTEMPTS_PER_NODE)
if (maxNodeAttempts >= maxTaskFailures) {
throw new IllegalArgumentException(s"${config.MAX_TASK_ATTEMPTS_PER_NODE.key} " +
s"( = ${maxNodeAttempts}) was >= ${config.TASK_MAX_FAILURES.key} " +
s"( = ${maxTaskFailures} ). Though excludeOnFailure is enabled, with this configuration, " +
s"Spark will not be robust to one bad node. Decrease " +
s"${config.MAX_TASK_ATTEMPTS_PER_NODE.key}, increase ${config.TASK_MAX_FAILURES.key}, " +
s"or disable excludeOnFailure with ${config.EXCLUDE_ON_FAILURE_ENABLED.key}")
}
}
}
private final case class ExcludedExecutor(node: String, expiryTime: Long)
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