code: func parseKubeHost(host string) (string, error) {
  	u, err := url.Parse(host)
  	if err != nil {
  		return "", trace.Wrap(err, "failed to parse kubernetes host")
  	}
  	if _, _, err := net.SplitHostPort(u.Host); err != nil {
  		// add default HTTPS port
  		return fmt.Sprintf("%v:443", u.Host), nil
  	}
  	return u.Host, nil
  }
docs: // parseKubeHost parses and formats kubernetes hostname
  // to host:port format, if no port it set,
  // it assumes default HTTPS port