nginx.conf

worker_processes  1;

events {
    worker_connections  1024;
}

http {
    include       mime.types;
    default_type  application/octet-stream;

    sendfile        on;

    keepalive_timeout  65;

    server {
      server_name site1.example.com;

      # app1 reverse proxy follow
      location / {
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_pass http://192.168.1.10:8080/;
      }
    }

    server {
      server_name site2.example.com;

      # app1 reverse proxy follow
      location / {
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_pass http://192.168.1.11:8080/;
      }
    }

    include servers/*;
}

Make sure to change site.example.com and 192.168.1.10:8080 to the proper path.