---
prelude: |
    The 18.0.0 release includes many new features and bug fixes. It is
    difficult to cover all the changes that have been introduced. Please at
    least read the upgrade section which describes the required actions to
    upgrade your cloud from 17.0.0 (Queens) to 18.0.0 (Rocky).

    That said, a few major changes are worth mentioning. This is not an
    exhaustive list:

    - The latest Compute API microversion supported for Rocky is v2.65. Details
      on REST API microversions added since the 17.0.0 Queens release can be
      found in the `REST API Version History`_ page.

    - Nova is now using the new Neutron port binding API to minimize network
      downtime during live migrations. See the `related spec`_ for more
      details.

    - Volume-backed instances will no longer report ``root_gb`` usage for new
      instances and existing instances will heal during move operations.

    - Several REST APIs specific to nova-network were removed and the core
      functionality of nova-network is planned to be removed in the 19.0.0
      Stein release.

    - A ``nova-manage db purge`` command to `purge archived shadow table data`_
      is now available. A new ``--purge`` option is also available for the
      ``nova-manage db archive_deleted_rows`` command.

    - It is now possible to `disable a cell`_ to stop scheduling to a cell by
      using the ``nova-manage cell_v2 update_cell`` command.

    - The libvirt compute driver now supports trusted image certificates when
      using the 2.63 compute API microversion. See the `image signature
      certificate validation`_ documentation for more details.

    - It is now possible to configure a separate database for the placement
      service, which could help in easing the eventual placement service
      extraction from Nova and data migration associated with it.

    - A ``nova-manage placement heal_allocations`` command is now available to
      allow users of the CachingScheduler to get the placement service
      populated for their eventual migration to the FilterScheduler. The
      CachingScheduler is deprecated and could be removed as early as Stein.

    - The placement service now supports granular RBAC policy rules
      configuration. See the `placement policy`_ documentation for details.

    - A new zVM virt driver is now available.

    - The nova-consoleauth service has been deprecated.

    .. _REST API Version History: https://docs.openstack.org/nova/latest/reference/api-microversion-history.html
    .. _related spec: https://specs.openstack.org/openstack/nova-specs/specs/rocky/approved/neutron-new-port-binding-api.html
    .. _purge archived shadow table data: https://docs.openstack.org/nova/latest/cli/nova-manage.html#nova-database
    .. _disable a cell: https://docs.openstack.org/nova/latest/cli/nova-manage.html#nova-cells-v2
    .. _image signature certificate validation: https://docs.openstack.org/nova/latest/user/certificate-validation.html
    .. _placement policy: https://docs.openstack.org/nova/latest/configuration/placement-policy.html
