I have one FCGI process and its three instances are running on three different ports.

I am using nginx as reverse proxy server and now I want to use it for load balancing also. But I don't know how to configure it for fcgi processes.

I have configuration like this: 

```
location /abc {  
    fastcgi_pass backend;
}

upstream backend {

} 

```

I can use the configuration mentioned in 2nd answer and it also works fine.
<https://serverfault.com/questions/598202/make-nginx-to-pass-hostname-of-the-upstream-when-reverseproxying>

But I want to know how can I write fcgi process in upstream and how to pass some params to that fcgi process. Main problem is that I have to pass some variables coming through front-end request.