hadoop job -kill 和 yarn application -kill 区别

hadoop job -kill 调用的是CLI.java里面的job.killJob(); 这里会分几种情况，如果是能查询到状态是RUNNING的话，是直接向AppMaster发送kill请求的。
YARNRunner.java

  @Override
  public void killJob(JobID arg0) throws IOException, InterruptedException {
    /* check if the status is not running, if not send kill to RM */
    JobStatus status = clientCache.getClient(arg0).getJobStatus(arg0);
    ApplicationId appId = TypeConverter.toYarn(arg0).getAppId();
 
    // get status from RM and return
    if (status == null) {
      killUnFinishedApplication(appId);
      return;
    }
 
    if (status.getState() != JobStatus.State.RUNNING) {
      killApplication(appId);
      return;
    }
 
    try {
      /* send a kill to the AM */
      clientCache.getClient(arg0).killJob(arg0);
      long currentTimeMillis = System.currentTimeMillis();
      long timeKillIssued = currentTimeMillis;
      while ((currentTimeMillis < timeKillIssued + 10000L)
          && !isJobInTerminalState(status)) {
        try {
          Thread.sleep(1000L);
        } catch (InterruptedException ie) {
          /** interrupted, just break */
          break;
        }
        currentTimeMillis = System.currentTimeMillis();
        status = clientCache.getClient(arg0).getJobStatus(arg0);
        if (status == null) {
          killUnFinishedApplication(appId);
          return;
        }
      }
    } catch(IOException io) {
      LOG.debug("Error when checking for application status", io);
    }
    if (status != null && !isJobInTerminalState(status)) {
      killApplication(appId);
    }
  }

MRClientService.java

    @SuppressWarnings("unchecked")
    @Override
    public KillJobResponse killJob(KillJobRequest request) 
      throws IOException {
      JobId jobId = request.getJobId();
      UserGroupInformation callerUGI = UserGroupInformation.getCurrentUser();
      String message = "Kill job " + jobId + " received from " + callerUGI
          + " at " + Server.getRemoteAddress();
      LOG.info(message);
      verifyAndGetJob(jobId, JobACL.MODIFY_JOB);
      appContext.getEventHandler().handle(
          new JobDiagnosticsUpdateEvent(jobId, message));
      appContext.getEventHandler().handle(
          new JobEvent(jobId, JobEventType.JOB_KILL));
      KillJobResponse response = 
        recordFactory.newRecordInstance(KillJobResponse.class);
      return response;
    }

yarn application -kill 使用的是ApplicationCLI.java，是向RM发送kill请求

/**
   * Kills the application with the application id as appId
   * 
   * @param applicationId
   * @throws YarnException
   * @throws IOException
   */
  private void killApplication(String applicationId) throws YarnException,
      IOException {
    ApplicationId appId = ConverterUtils.toApplicationId(applicationId);
    ApplicationReport  appReport = null;
    try {
      appReport = client.getApplicationReport(appId);
    } catch (ApplicationNotFoundException e) {
      sysout.println("Application with id '" + applicationId +
          "' doesn't exist in RM.");
      throw e;
    }
 
    if (appReport.getYarnApplicationState() == YarnApplicationState.FINISHED
        || appReport.getYarnApplicationState() == YarnApplicationState.KILLED
        || appReport.getYarnApplicationState() == YarnApplicationState.FAILED) {
      sysout.println("Application " + applicationId + " has already finished ");
    } else {
      sysout.println("Killing application " + applicationId);
      client.killApplication(appId);
    }
  }

YarnClientImpl.java

  @Override
  public void killApplication(ApplicationId applicationId)
      throws YarnException, IOException {
    KillApplicationRequest request =
        Records.newRecord(KillApplicationRequest.class);
    request.setApplicationId(applicationId);
 
    try {
      int pollCount = 0;
      long startTime = System.currentTimeMillis();
 
      while (true) {
        KillApplicationResponse response =
            rmClient.forceKillApplication(request);
        if (response.getIsKillCompleted()) {
          LOG.info("Killed application " + applicationId);
          break;
        }
 
        long elapsedMillis = System.currentTimeMillis() - startTime;
        if (enforceAsyncAPITimeout() &&
            elapsedMillis >= this.asyncApiPollTimeoutMillis) {
          throw new YarnException("Timed out while waiting for application " +
            applicationId + " to be killed.");
        }
 
        if (++pollCount % 10 == 0) {
          LOG.info("Waiting for application " + applicationId + " to be killed.");
        }
        Thread.sleep(asyncApiPollIntervalMillis);
      }
    } catch (InterruptedException e) {
      LOG.error("Interrupted while waiting for application " + applicationId
          + " to be killed.");
    }
  }