FairScheduler源码任务分配

FairScheduler

private synchronized void nodeUpdate(RMNode nm) {
    if (LOG.isDebugEnabled()) {
      LOG.debug("nodeUpdate: " + nm + " cluster capacity: " + clusterResource);
    }
    eventLog.log("HEARTBEAT", nm.getHostName());
    FSSchedulerNode node = getFSSchedulerNode(nm.getNodeID());

    // Update resource if any change
    SchedulerUtils.updateResourceIfChanged(node, nm, clusterResource, LOG);
    
    List<UpdatedContainerInfo> containerInfoList = nm.pullContainerUpdates();
    List<ContainerStatus> newlyLaunchedContainers = new ArrayList<ContainerStatus>();
    List<ContainerStatus> completedContainers = new ArrayList<ContainerStatus>();
    for(UpdatedContainerInfo containerInfo : containerInfoList) {
      newlyLaunchedContainers.addAll(containerInfo.getNewlyLaunchedContainers());
      completedContainers.addAll(containerInfo.getCompletedContainers());
    } 
    // Processing the newly launched containers
    for (ContainerStatus launchedContainer : newlyLaunchedContainers) {
      containerLaunchedOnNode(launchedContainer.getContainerId(), node);
    }

    // Process completed containers
    for (ContainerStatus completedContainer : completedContainers) {
      ContainerId containerId = completedContainer.getContainerId();
      LOG.debug("Container FINISHED: " + containerId);
      completedContainer(getRMContainer(containerId),
          completedContainer, RMContainerEventType.FINISHED);
    }

      if (continuousSchedulingEnabled) {
      if (!completedContainers.isEmpty()) {
        attemptScheduling(node);
      }
    } else {
      attemptScheduling(node);    ////////////////开始调度分配
      
    }
    
    
    private synchronized void attemptScheduling(FSSchedulerNode node) {
    // Assign new containers...
    // 1. Check for reserved applications
    // 2. Schedule if there are no reservations

    AppSchedulable reservedAppSchedulable = node.getReservedAppSchedulable();
    if (reservedAppSchedulable != null) {
      Priority reservedPriority = node.getReservedContainer().getReservedPriority();
      if (!reservedAppSchedulable.hasContainerForNode(reservedPriority, node)) {
        // Don't hold the reservation if app can no longer use it
        LOG.info("Releasing reservation that cannot be satisfied for application "
            + reservedAppSchedulable.getApp().getApplicationAttemptId()
            + " on node " + node);
        reservedAppSchedulable.unreserve(reservedPriority, node);
        reservedAppSchedulable = null;
      } else {
        // Reservation exists; try to fulfill the reservation
        if (LOG.isDebugEnabled()) {
          LOG.debug("Trying to fulfill reservation for application "
              + reservedAppSchedulable.getApp().getApplicationAttemptId()
              + " on node: " + node);
        }
        
        node.getReservedAppSchedulable().assignReservedContainer(node);
      }
    }
    if (reservedAppSchedulable == null) {
      // No reservation, schedule at queue which is farthest below fair share
      int assignedContainers = 0;
      while (node.getReservedContainer() == null) {
        boolean assignedContainer = false;
        if (!queueMgr.getRootQueue().assignContainer(node).equals(  /////////////开始分配container
            Resources.none())) {
          assignedContainers++;
          assignedContainer = true;
        }
        if (!assignedContainer) { break; }
        if (!assignMultiple) { break; }
        if ((assignedContainers >= maxAssign) && (maxAssign > 0)) { break; }
      }
    }
    
    FSParentQueue
    
 public Resource assignContainer(FSSchedulerNode node) {
    Resource assigned = Resources.none();

    // If this queue is over its limit, reject
    if (!assignContainerPreCheck(node)) {
      return assigned;
    }

    Collections.sort(childQueues, policy.getComparator());//olicy.getComparator()会排序，如果queue小于最低保障资源，选择正在跑的任务数/最低量 最小的那个队列，否则选择正在跑的任务数/队列权重，最小的那个队列
    for (FSQueue child : childQueues) {
      assigned = child.assignContainer(node); //child对应的是FSLeafQueue
      if (!Resources.equals(assigned, Resources.none())) {
        break;
      }
    }
    return assigned;
  }
  
  //FSLeafQueue类
  
   public Resource assignContainer(FSSchedulerNode node) {
    Resource assigned = Resources.none();
    if (LOG.isDebugEnabled()) {
      LOG.debug("Node " + node.getNodeName() + " offered to queue: " +
          getName());
    }

    if (!assignContainerPreCheck(node)) {
      return assigned;
    }

    Comparator<Schedulable> comparator = policy.getComparator();  /////定义排序算法
    writeLock.lock();
    try {
      Collections.sort(runnableApps, comparator);  ////////////////选择该队列里的作业，按照正在跑的task数/作业权重
    } finally {
      writeLock.unlock();
    }
    readLock.lock();
    try {
      for (FSAppAttempt sched : runnableApps) {
        if (SchedulerAppUtils.isBlacklisted(sched, node, LOG)) {
          continue;
        }

        assigned = sched.assignContainer(node);
        if (!assigned.equals(Resources.none())) {
          break;
        }
      }
    } finally {
      readLock.unlock();
  
  
  
    public void setPolicy(SchedulingPolicy policy)
      throws AllocationConfigurationException {
    if (!SchedulingPolicy.isApplicableTo(policy, SchedulingPolicy.DEPTH_LEAF)) {
      throwPolicyDoesnotApplyException(policy);
    }
    super.policy = policy;
  }
  
  FairSharePolicy是其子类
    private FairShareComparator comparator = new FairShareComparator();
     public int compare(Schedulable s1, Schedulable s2) {
      double minShareRatio1, minShareRatio2;
      double useToWeightRatio1, useToWeightRatio2;
      Resource minShare1 = Resources.min(RESOURCE_CALCULATOR, null,
          s1.getMinShare(), s1.getDemand());
      Resource minShare2 = Resources.min(RESOURCE_CALCULATOR, null,
          s2.getMinShare(), s2.getDemand());
      boolean s1Needy = Resources.lessThan(RESOURCE_CALCULATOR, null,
          s1.getResourceUsage(), minShare1);
      boolean s2Needy = Resources.lessThan(RESOURCE_CALCULATOR, null,
          s2.getResourceUsage(), minShare2);
      minShareRatio1 = (double) s1.getResourceUsage().getMemory()
          / Resources.max(RESOURCE_CALCULATOR, null, minShare1, ONE).getMemory();
      minShareRatio2 = (double) s2.getResourceUsage().getMemory()
          / Resources.max(RESOURCE_CALCULATOR, null, minShare2, ONE).getMemory();
      useToWeightRatio1 = s1.getResourceUsage().getMemory() /
          s1.getWeights().getWeight(ResourceType.MEMORY);
      useToWeightRatio2 = s2.getResourceUsage().getMemory() /
          s2.getWeights().getWeight(ResourceType.MEMORY);
      int res = 0;
      if (s1Needy && !s2Needy)
        res = -1;
      else if (s2Needy && !s1Needy)
        res = 1;
      else if (s1Needy && s2Needy)
        res = (int) Math.signum(minShareRatio1 - minShareRatio2);
      else
        // Neither schedulable is needy
        res = (int) Math.signum(useToWeightRatio1 - useToWeightRatio2);
      if (res == 0) {
        // Apps are tied in fairness ratio. Break the tie by submit time and job
        // name to get a deterministic ordering, which is useful for unit tests.
        res = (int) Math.signum(s1.getStartTime() - s2.getStartTime());
        if (res == 0)
          res = s1.getName().compareTo(s2.getName());
      }
      return res;
    }
  }