--- features: - | Adds a concurrency limiter for number of nodes in states related to *Cleaning* and *Provisioning* operations across the ironic deployment. These settings default to a maximum number of concurrent deployments to ``250`` and a maximum number of concurrent deletes and cleaning operations to ``50``. These settings can be tuned using ``[conductor]max_concurrent_deploy`` and ``[conductor]max_concurrent_clean``, respectively. The defaults should generally be good for most operators in most cases. Large scale operators should evaluate the defaults and tune appropriately as this feature cannot be disabled, as it is a security mechanism. upgrade: - | Large scale operators should be aware that a new feature, referred to as "Concurrent Action Limit" was introduced as a security mechanism to provide a means to limit attackers, or faulty scripts, from potentially causing irreperable harm to an environment. This feature cannot be disabled, and operators are encouraged to tune the new settings ``[conductor]max_concurrent_deploy`` and ``[conductor]max_concurrent_clean`` to match the needs of their environment.