org.apache.drill.yarn.appMaster.Scheduler Maven / Gradle / Ivy
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* 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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*/
package org.apache.drill.yarn.appMaster;
import org.apache.drill.yarn.core.ContainerRequestSpec;
import org.apache.drill.yarn.core.LaunchSpec;
import org.apache.hadoop.yarn.api.records.Resource;
/**
* The scheduler describes the set of tasks to run. It provides the details
* required to launch each task and optionally a specification of the containers
* required to run the task.
*
* Schedulers can manage batch task (which do their job and complete), or
* persistent tasks (which run until terminated.)
*
* The scheduler tracks task completion (for batch tasks) and task levels (for
* persistent tasks.)
*/
public interface Scheduler {
public interface TaskManager {
int maxConcurrentAllocs();
LaunchSpec getLaunchSpec(Task task);
void allocated(EventContext context);
boolean stop(Task task);
void completed(EventContext context);
boolean isLive(EventContext context);
}
/**
* Controller-assigned priority for this scheduler. Used to differentiate
* container requests by scheduler.
*
* @param priority
*/
void setPriority(int priority);
/**
* Register the state object that tracks tasks launched by this scheduler.
*
* @param state
*/
void registerState(SchedulerState state);
String getName();
String getType();
/**
* Whether tasks from this scheduler should incorporate app startup/shutdown
* acknowledgements (acks) into the task lifecycle.
*/
boolean isTracked();
TaskManager getTaskManager();
/**
* Get the desired number of running tasks.
*
* @return The desired number of running tasks
*/
int getTarget();
/**
* Increase (positive) or decrease (negative) the number of desired tasks by
* the given amount.
*
* @param delta
*/
void change(int delta);
/**
* Set the number of desired tasks to the given level.
*
* @param level
* @return the actual resize level, which may be lower than the requested
* level if the system cannot provide the requested level
*/
int resize(int level);
void completed(Task task);
/**
* Adjust the number of running tasks to better track the desired number.
* Starts or stops tasks using the {@link SchedulerState} registered with
* {@link #registerState(SchedulerState)}.
*/
void adjust();
/**
* Return an estimate of progress given as a ratio of (work completed, total
* work).
*
* @return Estimate of progress.
*/
int[] getProgress();
/**
* If this is a batch scheduler, whether all tasks for the batch have
* completed. If this is a persistent task scheduler, always returns false.
*
* @return true if the scheduler has more tasks to run, false if the
* scheduler has no more tasks or manages a set of long-running tasks
*/
boolean hasMoreTasks();
/**
* For reporting, get the YARN resources requested by processes in
* this pool.
* @return The request spec.
*/
ContainerRequestSpec getResource( );
void limitContainerSize(Resource maxResource) throws AMException;
/**
* Maximum amount of time to wait when cancelling a job in the REQUESTING
* state. YARN will happily wait forever for a resource, this setting
* forcibly cancels the request at timeout.
*
* @return the number of seconds to wait for timeout. 0 means no timeout
*/
int getRequestTimeoutSec();
/**
* Informs the scheduler that a YARN resource request timed out. The scheduler
* can either retry or (more productively) assume that the requested node is
* not available and adjust its target size downward.
*/
void requestTimedOut();
}