public Map<String, String> grabGroupConfigMap() {
	  RequestGetGroupPacket request = new RequestGetGroupPacket(null);
	  request.setGroupName(groupName);
	  // force get group info, if client version equals server version, cs return empty
	  request.setConfigVersion(0);
	  
	  for (String addr  : configServerList) {
		  log.info("send request to " + addr);
		  ResponseGetGroupPacket response = null;
	      try {
	        TairClient client = factory.get(addr,
	            TairConstant.DEFAULT_CS_CONN_TIMEOUT, pstream);
	        response = (ResponseGetGroupPacket) client.invoke(request, TairConstant.DEFAULT_CS_TIMEOUT);
	      } catch (Exception e) {
	        log.error("get config failed from: " + addr, e);
	        continue;
	      }
	      if (response != null) {
	    	  return response.getConfigMap();
	      }
	  }
	  log.error("get config map null");
	  return null;
  }