---
upgrade:
  - |
    When using file-backed memory, the ``nova-compute`` service will now fail
    to start if the amount of reserved memory configured using ``[DEFAULT]
    reserved_host_memory_mb`` is equal to or greater than the total amount of
    memory configured using ``[libvirt] file_backed_memory``. Where reserved
    memory is less than the total amount of memory configured, a warning will
    be raised. This warning will become an error in a future release.

    The former combination is invalid as it would suggest reserved memory is
    greater than total memory available, while the latter is considered
    incorrect behavior as reserving of file-backed memory can and should be
    achieved by reducing the filespace allocated as memory by modifying
    ``[libvirt] file_backed_memory``.