import org.apache.hadoop.yarn.server.nodemanager.containermanager.application.ApplicationInitEvent; //导入依赖的package包/类
@SuppressWarnings("unchecked")
private void startContainerInternal(NMTokenIdentifier nmTokenIdentifier,
    ContainerTokenIdentifier containerTokenIdentifier,
    StartContainerRequest request) throws YarnException, IOException {

  /*
   * 1) It should save the NMToken into NMTokenSecretManager. This is done
   * here instead of RPC layer because at the time of opening/authenticating
   * the connection it doesn't know what all RPC calls user will make on it.
   * Also new NMToken is issued only at startContainer (once it gets renewed).
   * 
   * 2) It should validate containerToken. Need to check below things. a) It
   * is signed by correct master key (part of retrieve password). b) It
   * belongs to correct Node Manager (part of retrieve password). c) It has
   * correct RMIdentifier. d) It is not expired.
   */
  authorizeStartRequest(nmTokenIdentifier, containerTokenIdentifier);
 
  if (containerTokenIdentifier.getRMIdentifer() != nodeStatusUpdater
      .getRMIdentifier()) {
      // Is the container coming from unknown RM
      StringBuilder sb = new StringBuilder("\nContainer ");
      sb.append(containerTokenIdentifier.getContainerID().toString())
        .append(" rejected as it is allocated by a previous RM");
      throw new InvalidContainerException(sb.toString());
  }
  // update NMToken
  updateNMTokenIdentifier(nmTokenIdentifier);

  ContainerId containerId = containerTokenIdentifier.getContainerID();
  String containerIdStr = containerId.toString();
  String user = containerTokenIdentifier.getApplicationSubmitter();

  LOG.info("Start request for " + containerIdStr + " by user " + user);

  ContainerLaunchContext launchContext = request.getContainerLaunchContext();

  Credentials credentials = parseCredentials(launchContext);

  Container container =
      new ContainerImpl(getConfig(), this.dispatcher, launchContext,
        credentials, metrics, containerTokenIdentifier);
  ApplicationId applicationID =
      containerId.getApplicationAttemptId().getApplicationId();
  if (context.getContainers().putIfAbsent(containerId, container) != null) {
    NMAuditLogger.logFailure(user, AuditConstants.START_CONTAINER,
      "ContainerManagerImpl", "Container already running on this node!",
      applicationID, containerId);
    throw RPCUtil.getRemoteException("Container " + containerIdStr
        + " already is running on this node!!");
  }

  // Create the application
  Application application =
      new ApplicationImpl(dispatcher, this.aclsManager, user, applicationID,
        credentials, context);
  if (null == context.getApplications().putIfAbsent(applicationID,
    application)) {
    LOG.info("Creating a new application reference for app " + applicationID);

    dispatcher.getEventHandler().handle(
      new ApplicationInitEvent(applicationID, container.getLaunchContext()
        .getApplicationACLs()));
  }

  dispatcher.getEventHandler().handle(
    new ApplicationContainerInitEvent(container));

  this.context.getContainerTokenSecretManager().startContainerSuccessful(
    containerTokenIdentifier);
  NMAuditLogger.logSuccess(user, AuditConstants.START_CONTAINER,
    "ContainerManageImpl", applicationID, containerId);
  // TODO launchedContainer misplaced -> doesn't necessarily mean a container
  // launch. A finished Application will not launch containers.
  metrics.launchedContainer();
  metrics.allocateContainer(containerTokenIdentifier.getResource()); 
}