code: public static String[] adjustConf(String[] argv, Configuration conf) {
      String[] serviceId = new String[] { "" };
      String[] filteredArgv = DFSUtil.getServiceName(argv, serviceId);
      if (!serviceId[0].equals("")) {
        NameNode.checkServiceName(conf, serviceId[0]);
        DFSUtil.setGenericConf(conf, serviceId[0],
            AvatarNode.AVATARSERVICE_SPECIFIC_KEYS);
        NameNode.setupDefaultURI(conf);
      }
      return filteredArgv;
    }
docs: Adjust configuration for nameservice keys.