gistfile1.txt

    location @503 {
 
      add_header Maintenance "yes";
      error_page 405 = /system/maintenance.html;
 
      # Serve static assets if found.
      if (-f $request_filename) {
        break;
      }
 
      rewrite ^(.*)$ /system/maintenance.html break;
    }
    location = /system/maintenance.html {
      add_header Maintenance "yes";
    }