---
upgrade:
  - Only virt drivers in the nova.virt namespace may be loaded.
    This has been the case according to nova docs for several
    releases, but a quirk in some library code meant that loading
    things outside the namespace continued to work
    unintentionally. That has been fixed, which means "compute_driver
    = nova.virt.foo" is invalid (and now enforced as such), and should
    be "compute_driver = foo" instead.
other:

  - Virt drivers are no longer loaded with the import_object_ns
    function, which means that only virt drivers in the nova.virt
    namespace can be loaded.