---
prelude: >
    This release alters the cluster_scale_in and cluster_scale_out actions to
    no longer place the action into the actions table when a conflict is
    detected. This behavior is an improvement on the old way actions are
    processed as the requester will now receive immediate feedback from the
    API when an action cannot be processed. This release also honors the
    scaling action cooldown in the same manner by erring via the API when a
    scaling action cannot be processed due to cooldown.
features:
  - |
    [`blueprint scaling-action-acceptance <https://blueprints.launchpad.net/senlin/+spec/scaling-action-acceptance>`_]
    Scaling actions (IN or OUT) now validate that there is no conflicting
    action already being processed and will return an error via the API
    informing the end user if a conflict is detected. A conflicting action is
    detected when new action of either `CLUSTER_SCALE_IN` or
    `CLUSTER_SCALE_OUT` is attempted while there is already cluster scaling
    action in the action table in a pending status (READY, RUNNING, WAITING,
    ACTION_WAITING_LIFECYCLE_COMPLETION).
    Additionally the cooldown will be checked and enforced when a scaling
    action is requested. If the cooldown is being observed the requester will
    be informed of this when submitting the action via an error.
