internalAPIServerVirtualIP,
			advertiseAddress,
		},
	}

	// add cluster controlPlaneEndpoint if present (dns or ip)
	if len(cfg.ControlPlaneEndpoint) > 0 {
		if host, _, err := kubeadmutil.ParseHostPort(cfg.ControlPlaneEndpoint); err == nil {
			if ip := netutils.ParseIPSloppy(host); ip != nil {
				altNames.IPs = append(altNames.IPs, ip)
			} else {
				altNames.DNSNames = append(altNames.DNSNames, host)
			}

	return allErrs
}

// ValidateHostPort validates host[:port] endpoints
func ValidateHostPort(endpoint string, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}
	if _, _, err := kubeadmutil.ParseHostPort(endpoint); endpoint != "" && err != nil {
		allErrs = append(allErrs, field.Invalid(fldPath, endpoint, "endpoint is not valid"))
	}
	return allErrs
}