---
prelude: |
    The OpenStack 2023.1 (Nova 27.0.0) release includes many new features and
    bug fixes. Please be sure to read the upgrade section which describes the
    required actions to upgrade your cloud from 26.0.0 (Zed) to 27.0.0 (2023.1).
    As a reminder, OpenStack 2023.1 is our first `Skip-Level-Upgrade Release`__
    (starting from now, we name it a `SLURP release`) where you can
    rolling-upgrade your compute services from OpenStack Yoga as an experimental
    feature. Next SLURP release will be 2024.1.

    .. __: https://governance.openstack.org/tc/resolutions/20220210-release-cadence-adjustment.html

    There are a few major changes worth mentioning. This is not an exhaustive
    list:

    - The latest Compute API microversion supported for 2023.1 is `v2.95`__.

      .. __: https://docs.openstack.org/nova/latest/reference/api-microversion-history.html#maximum-in-2023.1

    - `PCI devices can now be scheduled <https://docs.openstack.org/nova/latest/admin/pci-passthrough.html#pci-tracking-in-placement>`_
      by Nova using the Placement API on a opt-in basis. This will help the
      nova-scheduler service to better schedule flavors that use PCI
      (non-Neutron related) resources, will generate less reschedules if an
      instance cannot be created on a candidate and will help the nova-scheduler
      to not miss valid candidates if the list was too large.

    - Operators can now ask Nova to `manage the power consumption of dedicated
      CPUs <https://docs.openstack.org/nova/latest/admin/cpu-topologies.html#configuring-cpu-power-management-for-dedicated-cores>`_
      so as to either offline them or change their governor if they're
      currently not in use by any instance or if the instance is stopped.

    - Nova will prevent unexpected compute service renames by `persisting a unique
      compute UUID on local disk <https://docs.openstack.org/nova/latest/admin/compute-node-identification.html>`_.
      This stored UUID will be considered the source of truth for knowing whether
      the compute service hostame has been modified or not. As a reminder,
      changing a compute hostname is forbidden, particularly when this compute is
      currently running instances on top of it.

    - `SPICE consoles <https://docs.openstack.org/nova/latest/admin/remote-console-access.html#spice-console>`_
      can now be configured with compression settings which include choices of the
      compression algorithm and the compression mode.

    - Fully-Qualified Domain Names are now considered valid for an instance
      hostname if you use the 2.94 API microversion.

    - By opting into 2.95 API microversion, evacuated instances will remain
      stopped on the destination host until manually started.

    - Nova APIs now `by default support new RBAC policies <https://docs.openstack.org/nova/latest/configuration/policy.html>`
      and scopes. See our `Policy Concepts documentation <https://docs.openstack.org/nova/latest/configuration/policy-concepts.html>`
      for further details.
