Add  [$proxy_alternative_upstream_name] 
Add  [$proxy_alternative_upstream_name] 

https://github.com/kubernetes/ingress-nginx/pull/4246
canhnt/ingress,kubernetes/ingress-nginx,kubernetes/ingress-nginx,caicloud/ingress,aledbf/ingress-nginx,canhnt/ingress,caicloud/ingress,kubernetes/ingress-nginx,caicloud/ingress,aledbf/ingress-nginx,canhnt/ingress,aledbf/ingress-nginx,kubernetes/ingress-nginx,aledbf/ingress-nginx,kubernetes/ingress-nginx,caicloud/ingress,canhnt/ingress