code: func GetControllerManagerProbeAddress(cfg *kubeadmapi.ClusterConfiguration) string {
  	if addr, exists := cfg.ControllerManager.ExtraArgs[kubeControllerManagerAddressArg]; exists {
  		return addr
  	}
  	return "127.0.0.1"
  }
docs: // GetControllerManagerProbeAddress returns the kubernetes controller manager probe address