---
upgrade:
  - |
    The default LVM configuration is now empty for all hosts, unless they are
    configured to use the ``devicemapper`` Docker storage driver (which is the
    default, but is expected to change in a future release).

    Note that while the default LVM configuration existed primarily for the
    ``devicemapper`` driver, it also included a ``docker-volumes`` logical
    volume mounted at ``/var/lib/docker/volumes`` for Docker volumes. If the
    ``docker-volumes`` volume is required on a host which is not configured to
    use the Docker ``devicemapper`` storage driver, the following variables may
    be used to enable it: ``compute_lvm_group_data_enabled``,
    ``controller_lvm_group_data_enabled``, ``seed_lvm_group_data_enabled``,
    ``storage_lvm_group_data_enabled``.
