maintenance page on nginx

nginx-maintenance.conf

# if /var/www/maintenance.html exists, don't use the proxy, instead, redirect everything to the maintenance page
# if it doesn't exist, proceed as normal
  
server #WHATEVER# {
  location #WHATEVER# {
    if (-f /var/www/maintenance.html) {
        return 503;
    }
    # REST OF NORMAL STUFF
  }

  error_page 503 @maintenance;
  location @maintenance {
    root /var/www/;
    rewrite ^(.*)$ /maintenance.html break;
  }