balanceo de cargas

upstream backend-servers {
   # Por defecto el algoritmo de balanceo es roud robin
   # descomentar (solo uno) para activar
   # least_conn;
   # ip_hash;

   # pueden ser nombres de host o dominio
   # si el servidor proxy puede resolver.
   # server backend1.example.com;
   # server backend2.example.com;

   server 1.2.3.4;
   server 5.6.7.8;
}


server {
    listen 80;

    server_name tu-dominio.com;

    location / {
        proxy_pass http://backend-servers;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }
}