func getMatchAllCluster(er *route.RouteConfiguration) string {
	if len(er.GetVirtualHosts()) != 1 {
		return ""
	}
	vh := er.GetVirtualHosts()[0]
	if !reflect.DeepEqual(vh.Domains, []string{"*"}) {
		return ""
	}
	if len(vh.GetRoutes()) != 1 {
		return ""
	}
	r := vh.GetRoutes()[0]
	if r.GetMatch().GetPrefix() != "/" {
		return ""
	}