void launchWorkerNode(Container container) throws IOException, YarnException {
    Map<String, String> env = System.getenv();
    ContainerLaunchContext workerContext = Records.newRecord(ContainerLaunchContext.class);

    LocalResource workerJar = Records.newRecord(LocalResource.class);
    setupWorkerJar(workerJar);
    workerContext.setLocalResources(Collections.singletonMap("socialite.jar", workerJar));
    System.out.println("[Master] workerJar:" + workerJar);

    Map<String, String> workerEnv = new HashMap<String, String>(env);
    setupWorkerEnv(workerEnv);
    workerContext.setEnvironment(workerEnv);

    String opts = "-Dsocialite.master=" + NetUtils.getHostname().split("/")[1] + " ";
    opts += "-Dsocialite.worker.num_threads=" + ClusterConf.get().getNumWorkerThreads() + " ";
    workerContext.setCommands(
        Collections.singletonList(
            "$JAVA_HOME/bin/java -ea "
                + env.get("JVM_OPTS")
                + " "
                + env.get("SOCIALITE_OPTS")
                + " "
                + opts
                + " "
                + "socialite.dist.worker.WorkerNode"
                + " 1>"
                + ApplicationConstants.LOG_DIR_EXPANSION_VAR
                + "/stdout"
                + " 2>"
                + ApplicationConstants.LOG_DIR_EXPANSION_VAR
                + "/stderr"));
    nmClient.startContainer(container, workerContext);
    L.info("Launched worker node (container:" + container.getId() + ")");
  }
  void addToEnv(Map<String, String> env, String variable, String value) {
    String classPathSep = ApplicationConstants.CLASS_PATH_SEPARATOR;
    String val = env.get(variable);
    if (val == null) {
      val = value;
    } else {
      val = val + classPathSep + value;
    }

    env.put(StringInterner.weakIntern(variable), StringInterner.weakIntern(val));
  }