code: public EmbeddedGobblin mrMode() throws IOException {
      this.sysConfigOverrides.put(ConfigurationKeys.JOB_LAUNCHER_TYPE_KEY, JobLauncherFactory.JobLauncherType.MAPREDUCE.name());
      this.builtConfigMap.put(ConfigurationKeys.FS_URI_KEY, FileSystem.get(new Configuration()).getUri().toString());
      this.builtConfigMap.put(ConfigurationKeys.MR_JOB_ROOT_DIR_KEY, "/tmp/EmbeddedGobblin_" + System.currentTimeMillis());
      this.distributeJarsFunction = new Runnable() {
        @Override
        public void run() {
          // Add jars needed at runtime to the sys config so MR job launcher will add them to distributed cache.
          EmbeddedGobblin.this.sysConfigOverrides.put(ConfigurationKeys.JOB_JAR_FILES_KEY,
              Joiner.on(",").join(getPrioritizedDistributedJars()));
        }
      };
      return this;
    }
docs: Specify job should run in MR mode.