'Returns an error if prerequisites aren\'t met.'

def check_for_setup_error(self):

    if (rados is None):
        msg = _('rados    and    rbd    python    libraries    not    found')
        raise exception.VolumeBackendAPIException(data=msg)
    for attr in ['rbd_cluster_name', 'rbd_pool']:
        val = getattr(self.configuration, attr)
        if (not val):
            raise exception.InvalidConfigurationValue(option=attr, value=val)
    with RADOSClient(self):
        pass
