/**
* 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.hadoop.mapreduce.v2.app;
import java.util.Iterator;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.mapreduce.MRJobConfig;
import org.apache.hadoop.mapreduce.v2.api.records.TaskAttemptId;
import org.apache.hadoop.mapreduce.v2.app.job.event.TaskAttemptDiagnosticsUpdateEvent;
import org.apache.hadoop.mapreduce.v2.app.job.event.TaskAttemptEvent;
import org.apache.hadoop.mapreduce.v2.app.job.event.TaskAttemptEventType;
import org.apache.hadoop.yarn.Clock;
import org.apache.hadoop.yarn.event.EventHandler;
import org.apache.hadoop.yarn.service.AbstractService;
/**
* This class keeps track of tasks that have already been launched. It
* determines if a task is alive and running or marks a task as dead if it does
* not hear from it for a long time.
*
*/
@SuppressWarnings({"unchecked", "rawtypes"})
public class TaskHeartbeatHandler extends AbstractService {
private static final Log LOG = LogFactory.getLog(TaskHeartbeatHandler.class);
//thread which runs periodically to see the last time since a heartbeat is
//received from a task.
private Thread lostTaskCheckerThread;
private volatile boolean stopped;
private int taskTimeOut = 5 * 60 * 1000;// 5 mins
private int taskTimeOutCheckInterval = 30 * 1000; // 30 seconds.
private final EventHandler eventHandler;
private final Clock clock;
private ConcurrentMap<TaskAttemptId, Long> runningAttempts;
public TaskHeartbeatHandler(EventHandler eventHandler, Clock clock,
int numThreads) {
super("TaskHeartbeatHandler");
this.eventHandler = eventHandler;
this.clock = clock;
runningAttempts =
new ConcurrentHashMap<TaskAttemptId, Long>(16, 0.75f, numThreads);
}
@Override
public void init(Configuration conf) {
super.init(conf);
taskTimeOut = conf.getInt(MRJobConfig.TASK_TIMEOUT, 5 * 60 * 1000);
taskTimeOutCheckInterval =
conf.getInt(MRJobConfig.TASK_TIMEOUT_CHECK_INTERVAL_MS, 30 * 1000);
}
@Override
public void start() {
lostTaskCheckerThread = new Thread(new PingChecker());
lostTaskCheckerThread.setName("TaskHeartbeatHandler PingChecker");
lostTaskCheckerThread.start();
super.start();
}
@Override
public void stop() {
stopped = true;
lostTaskCheckerThread.interrupt();
super.stop();
}
public void receivedPing(TaskAttemptId attemptID) {
//only put for the registered attempts
//TODO throw an exception if the task isn't registered.
runningAttempts.replace(attemptID, clock.getTime());
}
public void register(TaskAttemptId attemptID) {
runningAttempts.put(attemptID, clock.getTime());
}
public void unregister(TaskAttemptId attemptID) {
runningAttempts.remove(attemptID);
}
private class PingChecker implements Runnable {
@Override
public void run() {
while (!stopped && !Thread.currentThread().isInterrupted()) {
Iterator<Map.Entry<TaskAttemptId, Long>> iterator =
runningAttempts.entrySet().iterator();
// avoid calculating current time everytime in loop
long currentTime = clock.getTime();
while (iterator.hasNext()) {
Map.Entry<TaskAttemptId, Long> entry = iterator.next();
if (currentTime > entry.getValue() + taskTimeOut) {
//In case the iterator isn't picking up the latest.
// Extra lookup outside of the iterator - but only if the task
// is considered to be timed out.
Long taskTime = runningAttempts.get(entry.getKey());
if (taskTime != null && currentTime > taskTime + taskTimeOut) {
// task is lost, remove from the list and raise lost event
iterator.remove();
eventHandler.handle(new TaskAttemptDiagnosticsUpdateEvent(entry
.getKey(), "AttemptID:" + entry.getKey().toString()
+ " Timed out after " + taskTimeOut / 1000 + " secs"));
eventHandler.handle(new TaskAttemptEvent(entry.getKey(),
TaskAttemptEventType.TA_TIMED_OUT));
}
}
}
try {
Thread.sleep(taskTimeOutCheckInterval);
} catch (InterruptedException e) {
LOG.info("TaskHeartbeatHandler thread interrupted");
break;
}
}
}
}
}