---
features:
  - |
    Add support, in a new placement microversion 1.21, for the ``member_of``
    query parameter, representing one or more aggregate UUIDs. When supplied,
    it will filter the returned allocation candidates to only those
    resource_providers that are associated with ("members of") the specified
    aggregate(s). This parameter can have a value of either a single aggregate
    UUID, or a comma-separated list of aggregate UUIDs. When specifying more
    than one aggregate, a resource provider needs to be associated with at
    least one of the aggregates in order to be included; it does not have to be
    associated with all of them. Because of this, the list of UUIDs must be
    prefixed with ``in:`` to represent the logical ``OR`` of the selection.
