code: def backend_add(cls, name, backend):
          
          oper = cls.call(
              'hosting.rproxy.server.create', cls.usable_id(name), backend)
          cls.echo('Adding backend %s:%s into webaccelerator' %
                   (backend['ip'], backend['port']))
          cls.display_progress(oper)
          cls.echo('Backend added')
          return oper
docs: Add a backend into a webaccelerator