---
features:
  - |
    Added support for forbidden traits to the scheduler. A flavor extra spec
    is extended to support specifying the forbidden traits. The syntax of
    extra spec is ``trait:<trait_name>=forbidden``, for example:

    - trait:HW_CPU_X86_AVX2=forbidden
    - trait:STORAGE_DISK_SSD=forbidden

    The scheduler will pass the forbidden traits to the
    ``GET /allocation_candidates`` endpoint in the Placement API to include
    only resource providers that do not include the forbidden traits. Currently
    the only valid values are ``required`` and ``forbidden``. Any other values
    will be considered invalid.

    This requires that the Placement API version 1.22 is available before
    the ``nova-scheduler`` service can use this feature.

    The FilterScheduler is currently the only scheduler driver that supports
    this feature.
