org.apache.spark.scheduler.TaskScheduler.scala Maven / Gradle / Ivy
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* The ASF licenses this file to You under the Apache License, Version 2.0
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*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
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package org.apache.spark.scheduler
import org.apache.spark.scheduler.SchedulingMode.SchedulingMode
import org.apache.spark.storage.BlockManagerId
import org.apache.spark.util.AccumulatorV2
/**
* Low-level task scheduler interface, currently implemented exclusively by
* [[org.apache.spark.scheduler.TaskSchedulerImpl]].
* This interface allows plugging in different task schedulers. Each TaskScheduler schedules tasks
* for a single SparkContext. These schedulers get sets of tasks submitted to them from the
* DAGScheduler for each stage, and are responsible for sending the tasks to the cluster, running
* them, retrying if there are failures, and mitigating stragglers. They return events to the
* DAGScheduler.
*/
private[spark] trait TaskScheduler {
private val appId = "spark-application-" + System.currentTimeMillis
def rootPool: Pool
def schedulingMode: SchedulingMode
def start(): Unit
// Invoked after system has successfully initialized (typically in spark context).
// Yarn uses this to bootstrap allocation of resources based on preferred locations,
// wait for slave registrations, etc.
def postStartHook() { }
// Disconnect from the cluster.
def stop(): Unit
// Submit a sequence of tasks to run.
def submitTasks(taskSet: TaskSet): Unit
// Kill all the tasks in a stage and fail the stage and all the jobs that depend on the stage.
// Throw UnsupportedOperationException if the backend doesn't support kill tasks.
def cancelTasks(stageId: Int, interruptThread: Boolean): Unit
/**
* Kills a task attempt.
* Throw UnsupportedOperationException if the backend doesn't support kill a task.
*
* @return Whether the task was successfully killed.
*/
def killTaskAttempt(taskId: Long, interruptThread: Boolean, reason: String): Boolean
// Kill all the running task attempts in a stage.
// Throw UnsupportedOperationException if the backend doesn't support kill tasks.
def killAllTaskAttempts(stageId: Int, interruptThread: Boolean, reason: String): Unit
// Set the DAG scheduler for upcalls. This is guaranteed to be set before submitTasks is called.
def setDAGScheduler(dagScheduler: DAGScheduler): Unit
// Get the default level of parallelism to use in the cluster, as a hint for sizing jobs.
def defaultParallelism(): Int
/**
* Update metrics for in-progress tasks and let the master know that the BlockManager is still
* alive. Return true if the driver knows about the given block manager. Otherwise, return false,
* indicating that the block manager should re-register.
*/
def executorHeartbeatReceived(
execId: String,
accumUpdates: Array[(Long, Seq[AccumulatorV2[_, _]])],
blockManagerId: BlockManagerId): Boolean
/**
* Get an application ID associated with the job.
*
* @return An application ID
*/
def applicationId(): String = appId
/**
* Process a lost executor
*/
def executorLost(executorId: String, reason: ExecutorLossReason): Unit
/**
* Process a removed worker
*/
def workerRemoved(workerId: String, host: String, message: String): Unit
/**
* Get an application's attempt ID associated with the job.
*
* @return An application's Attempt ID
*/
def applicationAttemptId(): Option[String]
}