Example #1
1
  /**
   * We lost the task tracker! All task-tracker structures have already been updated. Just process
   * the contained tasks and any jobs that might be affected.
   */
  void lostTaskTracker(String trackerName) {
    LOG.info("Lost tracker '" + trackerName + "'");
    TreeSet lostTasks = (TreeSet) trackerToTaskMap.get(trackerName);
    trackerToTaskMap.remove(trackerName);

    if (lostTasks != null) {
      for (Iterator it = lostTasks.iterator(); it.hasNext(); ) {
        String taskId = (String) it.next();
        TaskInProgress tip = (TaskInProgress) taskidToTIPMap.get(taskId);

        // Tell the job to fail the relevant task
        JobInProgress job = tip.getJob();
        job.failedTask(tip, taskId, trackerName);
      }
    }
  }
Example #2
0
 public static void startTracker(Configuration conf) throws IOException {
   if (tracker != null) throw new IOException("JobTracker already running.");
   while (true) {
     try {
       tracker = new JobTracker(conf);
       break;
     } catch (IOException e) {
       LOG.log(Level.WARNING, "Starting tracker", e);
     }
     try {
       Thread.sleep(1000);
     } catch (InterruptedException e) {
     }
   }
   tracker.offerService();
 }
Example #3
0
  /** Start the JobTracker process, listen on the indicated port */
  JobTracker(Configuration conf) throws IOException {
    //
    // Grab some static constants
    //
    maxCurrentTasks = conf.getInt("mapred.tasktracker.tasks.maximum", 2);
    RETIRE_JOB_INTERVAL = conf.getLong("mapred.jobtracker.retirejob.interval", 24 * 60 * 60 * 1000);
    RETIRE_JOB_CHECK_INTERVAL = conf.getLong("mapred.jobtracker.retirejob.check", 60 * 1000);
    TASK_ALLOC_EPSILON = conf.getFloat("mapred.jobtracker.taskalloc.loadbalance.epsilon", 0.2f);
    PAD_FRACTION = conf.getFloat("mapred.jobtracker.taskalloc.capacitypad", 0.1f);
    MIN_SLOTS_FOR_PADDING = 3 * maxCurrentTasks;

    // This is a directory of temporary submission files.  We delete it
    // on startup, and can delete any files that we're done with
    this.conf = conf;
    JobConf jobConf = new JobConf(conf);
    this.systemDir = jobConf.getSystemDir();
    this.fs = FileSystem.get(conf);
    FileUtil.fullyDelete(fs, systemDir);
    fs.mkdirs(systemDir);

    // Same with 'localDir' except it's always on the local disk.
    jobConf.deleteLocalFiles(SUBDIR);

    // Set ports, start RPC servers, etc.
    InetSocketAddress addr = getAddress(conf);
    this.localMachine = addr.getHostName();
    this.port = addr.getPort();
    this.interTrackerServer = RPC.getServer(this, addr.getPort(), 10, false, conf);
    this.interTrackerServer.start();
    Properties p = System.getProperties();
    for (Iterator it = p.keySet().iterator(); it.hasNext(); ) {
      String key = (String) it.next();
      String val = (String) p.getProperty(key);
      LOG.info("Property '" + key + "' is " + val);
    }

    this.infoPort = conf.getInt("mapred.job.tracker.info.port", 50030);
    this.infoServer = new JobTrackerInfoServer(this, infoPort);
    this.infoServer.start();

    this.startTime = System.currentTimeMillis();

    new Thread(this.expireTrackers).start();
    new Thread(this.retireJobs).start();
    new Thread(this.initJobs).start();
  }
Example #4
0
  /**
   * Accept and process a new TaskTracker profile. We might have known about the TaskTracker
   * previously, or it might be brand-new. All task-tracker structures have already been updated.
   * Just process the contained tasks and any jobs that might be affected.
   */
  void updateTaskStatuses(TaskTrackerStatus status) {
    for (Iterator it = status.taskReports(); it.hasNext(); ) {
      TaskStatus report = (TaskStatus) it.next();
      TaskInProgress tip = (TaskInProgress) taskidToTIPMap.get(report.getTaskId());
      if (tip == null) {
        LOG.info(
            "Serious problem.  While updating status, cannot find taskid " + report.getTaskId());
      } else {
        JobInProgress job = tip.getJob();
        job.updateTaskStatus(tip, report);

        if (report.getRunState() == TaskStatus.SUCCEEDED) {
          job.completedTask(tip, report.getTaskId());
        } else if (report.getRunState() == TaskStatus.FAILED) {
          // Tell the job to fail the relevant task
          job.failedTask(tip, report.getTaskId(), status.getTrackerName());
        }
      }
    }
  }
Example #5
0
  ///////////////////////////////////////////////////////
  // Maintain lookup tables; called by JobInProgress
  // and TaskInProgress
  ///////////////////////////////////////////////////////
  void createTaskEntry(String taskid, String taskTracker, TaskInProgress tip) {
    LOG.info(
        "Adding task '"
            + taskid
            + "' to tip "
            + tip.getTIPId()
            + ", for tracker '"
            + taskTracker
            + "'");

    // taskid --> tracker
    taskidToTrackerMap.put(taskid, taskTracker);

    // tracker --> taskid
    TreeSet taskset = (TreeSet) trackerToTaskMap.get(taskTracker);
    if (taskset == null) {
      taskset = new TreeSet();
      trackerToTaskMap.put(taskTracker, taskset);
    }
    taskset.add(taskid);

    // taskid --> TIP
    taskidToTIPMap.put(taskid, tip);
  }
Example #6
0
  /**
   * A tracker wants to know if there's a Task to run. Returns a task we'd like the TaskTracker to
   * execute right now.
   *
   * <p>Eventually this function should compute load on the various TaskTrackers, and incorporate
   * knowledge of DFS file placement. But for right now, it just grabs a single item out of the
   * pending task list and hands it back.
   */
  public synchronized Task pollForNewTask(String taskTracker) {
    //
    // Compute average map and reduce task numbers across pool
    //
    int avgMaps = 0;
    int avgReduces = 0;
    int numTaskTrackers;
    TaskTrackerStatus tts;
    synchronized (taskTrackers) {
      numTaskTrackers = taskTrackers.size();
      tts = (TaskTrackerStatus) taskTrackers.get(taskTracker);
    }
    if (numTaskTrackers > 0) {
      avgMaps = totalMaps / numTaskTrackers;
      avgReduces = totalReduces / numTaskTrackers;
    }
    int totalCapacity = numTaskTrackers * maxCurrentTasks;
    //
    // Get map + reduce counts for the current tracker.
    //
    if (tts == null) {
      LOG.warning("Unknown task tracker polling; ignoring: " + taskTracker);
      return null;
    }

    int numMaps = tts.countMapTasks();
    int numReduces = tts.countReduceTasks();

    //
    // In the below steps, we allocate first a map task (if appropriate),
    // and then a reduce task if appropriate.  We go through all jobs
    // in order of job arrival; jobs only get serviced if their
    // predecessors are serviced, too.
    //

    //
    // We hand a task to the current taskTracker if the given machine
    // has a workload that's equal to or less than the averageMaps
    // +/- TASK_ALLOC_EPSILON.  (That epsilon is in place in case
    // there is an odd machine that is failing for some reason but
    // has not yet been removed from the pool, making capacity seem
    // larger than it really is.)
    //
    synchronized (jobsByArrival) {
      if ((numMaps < maxCurrentTasks) && (numMaps <= (avgMaps + TASK_ALLOC_EPSILON))) {

        int totalNeededMaps = 0;
        for (Iterator it = jobsByArrival.iterator(); it.hasNext(); ) {
          JobInProgress job = (JobInProgress) it.next();
          if (job.getStatus().getRunState() != JobStatus.RUNNING) {
            continue;
          }

          Task t = job.obtainNewMapTask(taskTracker, tts);
          if (t != null) {
            return t;
          }

          //
          // Beyond the highest-priority task, reserve a little
          // room for failures and speculative executions; don't
          // schedule tasks to the hilt.
          //
          totalNeededMaps += job.desiredMaps();
          double padding = 0;
          if (totalCapacity > MIN_SLOTS_FOR_PADDING) {
            padding = Math.min(maxCurrentTasks, totalNeededMaps * PAD_FRACTION);
          }
          if (totalNeededMaps + padding >= totalCapacity) {
            break;
          }
        }
      }

      //
      // Same thing, but for reduce tasks
      //
      if ((numReduces < maxCurrentTasks) && (numReduces <= (avgReduces + TASK_ALLOC_EPSILON))) {

        int totalNeededReduces = 0;
        for (Iterator it = jobsByArrival.iterator(); it.hasNext(); ) {
          JobInProgress job = (JobInProgress) it.next();
          if (job.getStatus().getRunState() != JobStatus.RUNNING) {
            continue;
          }

          Task t = job.obtainNewReduceTask(taskTracker, tts);
          if (t != null) {
            return t;
          }

          //
          // Beyond the highest-priority task, reserve a little
          // room for failures and speculative executions; don't
          // schedule tasks to the hilt.
          //
          totalNeededReduces += job.desiredReduces();
          double padding = 0;
          if (totalCapacity > MIN_SLOTS_FOR_PADDING) {
            padding = Math.min(maxCurrentTasks, totalNeededReduces * PAD_FRACTION);
          }
          if (totalNeededReduces + padding >= totalCapacity) {
            break;
          }
        }
      }
    }
    return null;
  }