nginx proxy_pass to dynamic url - nginx

Question

I have multiple backend servers and I want to proxy all servers using a single nginx server instance. I don't want to change nginx.conf whenever I add a new backend server.
For example: Server 1 : 192.168.10.1:8080, Server2: 192.168.10.2:8080, etc
Nginx is running on example.com. I want to access Server1 by using example.com?ip=192.168.10.1, example.com?ip=192.168.10.2 etc
I tried this configuration, but it is giving 500 error page.
location / {
proxy_pass http://$arg_ip:8080;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
}
Is there something I am missing? Is there any other way of achieving this?

Answer 1

server {
server_name dynamic_host;
listern 8080;
#resolver 8.8.8.8;
#seems you don't need resolver because you use ip address
location / {
if ( $arg_address != "" ) {
proxy_pass $arg_address;
#proxy_pass $arg_address$uri
#proxy_pass $arg_address$request_uri
}
}
}
the difference between the three proxy_pass
$proxy_address
example.com?address=http://192.168.10.2:8080/ goes to
http://192.168.10.2:8080/
$proxy_address$uri
example.com/test/path?address=http://192.168.10.2:8080/ goes to
http://192.168.10.2:8080/test/path
$proxy_address$request_uri
example.com/test/path?address=http://192.168.10.2:8080/&param=value goes to
http://192.168.10.2:8080/test/path?address=http://192.168.10.2:8080/&param=value
you can change the param address to ip, in this case, don't forget to change $arg_address to $arg_ip.
reference:
http://nginx.org/en/docs/http/ngx_http_core_module.html#variables