'Get the timing configuration for powering down this instance.'

def _get_power_off_values(self, context, instance, clean_shutdown):

    if clean_shutdown:
        timeout = compute_utils.get_value_from_system_metadata(instance, key='image_os_shutdown_timeout', type=int, default=CONF.shutdown_timeout)
        retry_interval = self.SHUTDOWN_RETRY_INTERVAL
    else:
        timeout = 0
        retry_interval = 0
    return (timeout, retry_interval)
