---
upgrade:
  - |
    The defalut value for policy rule
    ``os_compute_api:servers:create:zero_disk_flavor`` has changed from
    ``rule:admin_or_owner`` to ``rule:admin_api`` which means that by default,
    users without the admin role will not be allowed to create servers using
    a flavor with ``disk=0`` *unless* they are creating a volume-backed server.
    If you have these kinds of flavors, you may need to take action or
    temporarily override the policy rule. Refer to
    `bug 1739646 <https://launchpad.net/bugs/1739646>`_ for more details.