nginx-upstream-config.conf

location / {                         
　　proxy_pass_header Server;                         
　　proxy_set_header Host $http_host;                         
　　proxy_set_header X-Real-IP $remote_addr;                         
　　proxy_set_header X-Scheme $scheme;                         
　　proxy_pass http://frontends;                         
　　proxy_next_upstream error;

}