---
prelude: >
    This release alters the behavior of cluster and node APIs which create, update or
    delete either resource.  In the previous release those API calls would be
    accepted even if the target resource was already locked by another action.
    The old implementation would wait until the other action released the lock
    and then continue to execute the desired action.  With the new implementation
    any API calls for cluster or node that modify said resource will be rejected
    with 409 conflict.
features:
  - |
    [`blueprint fail-fast-locked-resource <https://blueprints.launchpad.net/senlin/+spec/fail-fast-locked-resource>`_]
    POST, PATCH or DELETE API calls for clusters or nodes that require a lock are
    rejected with 409 resource conflict if another action is already holding a
    lock on the target resource.
