{% data variables.product.prodname_actions_runner_controller %} (ARC) is a Kubernetes operator that orchestrates and scales self-hosted runners for {% data variables.product.prodname_actions %}. For more information, see Operator pattern in the Kubernetes documentation.
With ARC, you can create runner scale sets that automatically scale based on the number of workflows running in your repository, organization, or enterprise. Because controlled runners can be ephemeral and based on containers, new runner instances can scale up or down rapidly and cleanly. For more information about autoscaling, see "AUTOTITLE."