Hadoop2.x Yarn作业提交（服务端）

问题导读：
1.服务于作业提交的server为ClientRMService，默认监听哪个端口？
2.如何获取作业id?








RM接收到客户端作业提交请求时会通过RPC server做回应，其实客户端就是通过ApplicationClientProtocol的RPC客户端提交作业的，在提交阶段的代码中，首先会调用getNewApplication来获得一个GetNewApplicationResponse，该返回类中包含了APP的ApplicationId，调度器资源信息。需要注意的是在RM的服务端有多个RPCserver，服务于作业提交的server为ClientRMService，默认监听18032端口，可以通过yarn.resourcemanager.address配置，下面是服务端的getNewApplication，包含在ClientRMService.java中

@Override  
public GetNewApplicationResponse getNewApplication(  
    GetNewApplicationRequest request) throws YarnException {  
  //构建GetNewApplicationResponse对象  
  GetNewApplicationResponse response = recordFactory  
      .newRecordInstance(GetNewApplicationResponse.class);  
  //设置作业ID  
  response.setApplicationId(getNewApplicationId());  
  // 设置调度器资源信息，作业ID设置完后，接下来设置调度器资源，目前包括CPU 内存两部分信息，相关函数有：yarn.scheduler.minimum-allocation-mb yarn.scheduler.minimum-allocation-vcores yarn.scheduler.maximum-allocation-mb yarn.scheduler.maximum-allocation-vcores，这些信息在调度器启动时指定。  
  
  
  response.setMaximumResourceCapability(scheduler  
      .getMaximumResourceCapability());         
    
  return response;  
}  
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作业ID的获得通过getNewApplicationId，是由集群启动时间戳和计数器计算得来

ApplicationId getNewApplicationId() {  
  ApplicationId applicationId = org.apache.hadoop.yarn.server.utils.BuilderUtils  
      .newApplicationId(recordFactory, ResourceManager.getClusterTimeStamp(),  
          applicationCounter.incrementAndGet());  
  LOG.info("Allocated new applicationId: " + applicationId.getId());  
  return applicationId;  
}  
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作业ID的构建函数

public static ApplicationId newInstance(long clusterTimestamp, int id) {  
  ApplicationId appId = Records.newRecord(ApplicationId.class);  
  appId.setClusterTimestamp(clusterTimestamp);  
  appId.setId(id);  
  appId.build();  
  return appId;  
}  
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在客户端接收到返回信息后，便知道了自己的作业ID、资源分配的最大值，下面进入提交阶段，依然在ClientRMService中

@Override  
public SubmitApplicationResponse submitApplication(  
    SubmitApplicationRequest request) throws YarnException {  
  //获得提交上下文  
  ApplicationSubmissionContext submissionContext = request  
      .getApplicationSubmissionContext();  
  //获得作业ID  
  ApplicationId applicationId = submissionContext.getApplicationId();  
  
  
  // ApplicationSubmissionContext needs to be validated for safety - only  
  // those fields that are independent of the RM's configuration will be  
  // checked here, those that are dependent on RM configuration are validated  
  // in RMAppManager.  
    //进入一系列的安全校验  
  String user = null;  
  try {  
    // 提交账户是否安全  
    user = UserGroupInformation.getCurrentUser().getShortUserName();  
  } catch (IOException ie) {  
    LOG.warn("Unable to get the current user.", ie);  
    RMAuditLogger.logFailure(user, AuditConstants.SUBMIT_APP_REQUEST,  
        ie.getMessage(), "ClientRMService",  
        "Exception in submitting application", applicationId);  
    throw RPCUtil.getRemoteException(ie);  
  }  
  
  
  // Though duplication will checked again when app is put into rmContext,  
  // but it is good to fail the invalid submission as early as possible.  
  //作业ID是否已经存在  
  if (rmContext.getRMApps().get(applicationId) != null) {  
    String message = "Application with id " + applicationId +  
        " is already present! Cannot add a duplicate!";  
    LOG.warn(message);  
    RMAuditLogger.logFailure(user, AuditConstants.SUBMIT_APP_REQUEST,  
        message, "ClientRMService", "Exception in submitting application",  
        applicationId);  
    throw RPCUtil.getRemoteException(message);  
  }  
    //设置作业队列  
  if (submissionContext.getQueue() == null) {  
    submissionContext.setQueue(YarnConfiguration.DEFAULT_QUEUE_NAME);  
  }  
  //设置作业缺省名称  
  if (submissionContext.getApplicationName() == null) {  
    submissionContext.setApplicationName(  
        YarnConfiguration.DEFAULT_APPLICATION_NAME);  
  }  
  //设置作业类型  
  if (submissionContext.getApplicationType() == null) {  
    submissionContext  
      .setApplicationType(YarnConfiguration.DEFAULT_APPLICATION_TYPE);  
  } else {  
    //作业类型长度？？？有什么用？  
    if (submissionContext.getApplicationType().length() > YarnConfiguration.APPLICATION_TYPE_LENGTH) {  
      submissionContext.setApplicationType(submissionContext  
        .getApplicationType().substring(0,  
          YarnConfiguration.APPLICATION_TYPE_LENGTH));  
    }  
  }  
  
  
  try {  
    // call RMAppManager to submit application directly  
    //开始提交作业  
    rmAppManager.submitApplication(submissionContext,  
        System.currentTimeMillis(), user, false, null);  
  
  
    LOG.info("Application with id " + applicationId.getId() +   
        " submitted by user " + user);  
    RMAuditLogger.logSuccess(user, AuditConstants.SUBMIT_APP_REQUEST,  
        "ClientRMService", applicationId);  
  } catch (YarnException e) {  
    LOG.info("Exception in submitting application with id " +  
        applicationId.getId(), e);  
    RMAuditLogger.logFailure(user, AuditConstants.SUBMIT_APP_REQUEST,  
        e.getMessage(), "ClientRMService",  
        "Exception in submitting application", applicationId);  
    throw e;  
  }  
  
  
  SubmitApplicationResponse response = recordFactory  
      .newRecordInstance(SubmitApplicationResponse.class);  
  return response;  
}  
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作业提交阶段

@SuppressWarnings("unchecked")  
protected void submitApplication(  
    ApplicationSubmissionContext submissionContext, long submitTime,  
    String user, boolean isRecovered, RMState state) throws YarnException {  
  //获得作业ID  
  ApplicationId applicationId = submissionContext.getApplicationId();  
  //构建一个app并放入applicationACLS  
  RMAppImpl application =  
      createAndPopulateNewRMApp(submissionContext, submitTime, user);  
  //判断是否需要恢复  
  if (isRecovered) {  
    recoverApplication(state, application);  
    RMAppState rmAppState =  
        state.getApplicationState().get(applicationId).getState();  
    if (isApplicationInFinalState(rmAppState)) {  
      // We are synchronously moving the application into final state so that  
      // momentarily client will not see this application in NEW state. Also  
      // for finished applications we will avoid renewing tokens.  
      application  
          .handle(new RMAppEvent(applicationId, RMAppEventType.RECOVER));  
      return;  
    }  
  }  
    
  if (UserGroupInformation.isSecurityEnabled()) {  
    Credentials credentials = null;  
    try {  
      credentials = parseCredentials(submissionContext);  
    } catch (Exception e) {  
      LOG.warn(  
          "Unable to parse credentials.", e);  
      // Sending APP_REJECTED is fine, since we assume that the  
      // RMApp is in NEW state and thus we haven't yet informed the  
      // scheduler about the existence of the application  
      assert application.getState() == RMAppState.NEW;  
      this.rmContext.getDispatcher().getEventHandler().handle(  
          new RMAppRejectedEvent(applicationId, e.getMessage()));  
      throw RPCUtil.getRemoteException(e);  
    }  
    this.rmContext.getDelegationTokenRenewer().addApplication(  
        applicationId, credentials,  
        submissionContext.getCancelTokensWhenComplete(), isRecovered);  
  } else {  
    //触发app启动事件  
    this.rmContext.getDispatcher().getEventHandler()  
        .handle(new RMAppEvent(applicationId,  
            isRecovered ? RMAppEventType.RECOVER : RMAppEventType.START));  
  }  
}  
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application在下面函数中创建并加入相应集合，如果加入集合成功则代表作业提交成功

private RMAppImpl createAndPopulateNewRMApp(  
    ApplicationSubmissionContext submissionContext,  
    long submitTime, String user)  
    throws YarnException {  
  ApplicationId applicationId = submissionContext.getApplicationId();  
  validateResourceRequest(submissionContext);  
  //构建APP，submissionContext中包含了一个APP的绝大部分信息  
  RMAppImpl application =  
      new RMAppImpl(applicationId, rmContext, this.conf,  
          submissionContext.getApplicationName(), user,  
          submissionContext.getQueue(),  
          submissionContext, this.scheduler, this.masterService,  
          submitTime, submissionContext.getApplicationType());  
  
  
  // Concurrent app submissions with same applicationId will fail here  
  // Concurrent app submissions with different applicationIds will not  
  // influence each other  
  //再次判断作业是否存在，若不存在则放入hashMap中，一旦放入成功则表明作业提交成功  
  if (rmContext.getRMApps().putIfAbsent(applicationId, application) !=  
      null) {  
    String message = "Application with id " + applicationId  
        + " is already present! Cannot add a duplicate!";  
    LOG.warn(message);  
    throw RPCUtil.getRemoteException(message);  
  }  
  // Inform the ACLs Manager  
  this.applicationACLsManager.addApplication(applicationId,  
      submissionContext.getAMContainerSpec().getApplicationACLs());  
  return application;  
}  
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一个app包含的信息比较多，如下（RMAppImpl.java）

private static final Log LOG = LogFactory.getLog(RMAppImpl.class);  
private static final String UNAVAILABLE = "N/A";  
  
  
// Immutable fields  
private final ApplicationId applicationId;  
private final RMContext rmContext;  
private final Configuration conf;  
private final String user;  
private final String name;  
private final ApplicationSubmissionContext submissionContext;  
private final Dispatcher dispatcher;  
private final YarnScheduler scheduler;  
private final ApplicationMasterService masterService;  
private final StringBuilder diagnostics = new StringBuilder();  
private final int maxAppAttempts;  
private final ReadLock readLock;  
private final WriteLock writeLock;  
private final Map<ApplicationAttemptId, RMAppAttempt> attempts  
    = new LinkedHashMap<ApplicationAttemptId, RMAppAttempt>();  
private final long submitTime;  
private final Set<RMNode> updatedNodes = new HashSet<RMNode>();  
private final String applicationType;  
  
  
// Mutable fields  
private long startTime;  
private long finishTime = 0;  
private long storedFinishTime = 0;  
private RMAppAttempt currentAttempt;  
private String queue;  
@SuppressWarnings("rawtypes")  
private EventHandler handler;  
private static final FinalTransition FINAL_TRANSITION = new FinalTransition();  
private static final AppFinishedTransition FINISHED_TRANSITION =  
    new AppFinishedTransition();  
  
  
// These states stored are only valid when app is at killing or final_saving.  
private RMAppState stateBeforeKilling;  
private RMAppState stateBeforeFinalSaving;  
private RMAppEvent eventCausingFinalSaving;  
private RMAppState targetedFinalState;  
private RMAppState recoveredFinalState;  
  
  
Object transitionTodo;  
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