more infomation, refer to the panko docs[1] or code[2]

[1]: https://docs.openstack.org/panko/rocky/install/manual.html
[2]: https://github.com/openstack/panko/blob/9c4677f1784ed3353c31067e6e1bf74a0c86c037/panko/storage/__init__.py#L39

Change-Id: Ic7bdf555eb262005ca24f675cd8cee09d9bc3092
Closes-Bug: #1690843