func fillExternalIp(args *models.InstallerArguments, manifest models.Manifest, externalIp string) {
	if externalIp == "" {
		consulIp := strings.Split(args.ConsulIPs, ",")[0]
		conn, err := net.Dial("udp", consulIp+":65530")
		FailOnError(err)
		externalIp = strings.Split(conn.LocalAddr().String(), ":")[0]
	}
	args.ExternalIp = externalIp
}