class MemberDiscovery {

  public String getConfigServer() {
    synchronized (lock) {
      if (configServerAddresses.isEmpty()) {
        throw new IllegalStateException("Config center address is not available.");
      }
      int index = Math.abs(counter.get() % configServerAddresses.size());
      return configServerAddresses.get(index);
    }
  }

  public  MemberDiscovery(List<String> configCenterUri);

}