---
upgrade:
  - |
    Parts of the compute REST API are now relying on getting information from
    cells via their mappings in the ``nova_api`` database. This is to support
    multiple cells. For example, when listing compute hosts or services, all
    cells will be iterated in the API and the results will be returned.

    This change can have impacts, however, to deployment tooling that relies on
    parts of the API, like listing compute hosts, `before` the compute hosts
    are mapped using the ``nova-manage cell_v2 discover_hosts`` command.

    If you were using ``nova hypervisor-list`` after starting new nova-compute
    services to tell when to run ``nova-manage cell_v2 discover_hosts``, you
    should change your tooling to instead use one of the following commands::

      nova service-list --binary nova-compute [--host <hostname>]

      openstack compute service list --service nova-compute [--host <host>]

    As a reminder, there is also the
    ``[scheduler]/discover_hosts_in_cells_interval`` configuration option which
    can be used to automatically discover hosts from the nova-scheduler
    service.