---
prelude: |
    The 9.1.0 (Pike) release includes many new features and bug fixes.

    Please review the "Upgrade Notes" sections (for 8.0.0, 9.0.0, 9.0.1, and
    9.1.0) which describe the required actions to upgrade your installation
    from 7.0.x (Ocata) to 9.1.0 (Pike).

    A few major changes are worth mentioning. This is not an exhaustive list,
    and mostly includes changes from 9.0.0:

    - It is now possible to do rolling upgrades, starting with upgrading Ocata
      to Pike. For details, see
      https://docs.openstack.org/ironic/latest/admin/upgrade-guide.html.

    - The long-awaited support to boot from volumes is here. For details, see
      https://docs.openstack.org/ironic/latest/admin/boot-from-volume.html.

    - Full support for *hardware types* is available. There are hardware types
      for all *classic* drivers, and classic drivers can be `upgraded to
      hardware types <https://docs.openstack.org/ironic/latest/admin/upgrade-to-hardware-types.html>`_.
      The use of hardware types is preferred over the use of classic drivers,
      since classic drivers may be deprecated in the Queens release.

    - Adds the new ``redfish`` hardware type that supports the Redfish standard.
      For details, see
      https://docs.openstack.org/ironic/latest/admin/drivers/redfish.html.

    - The Compute service is changing the way bare metal nodes are scheduled,
      and will be using the node's ``resource_class`` to do this. For more
      details, see
      https://docs.openstack.org/ironic/latest/install/configure-nova-flavors.html#scheduling-based-on-resource-classes.

    - The Bare Metal service can now incorporate physical network information
      when attaching virtual interfaces (VIFs) via the new ``physical_network``
      field to the port object. For details, see
      https://docs.openstack.org/ironic/latest/admin/multitenancy.html#multitenancy-physnets.

    - The ssh-based drivers have been removed from ironic. Please see the 9.0.0
      "Upgrade Notes" section for more information.
