devops engineers are developing an order processing system where notifications are sent to a department whenever an order is placed for a product. the system also pushes identical notifications of the new order to a processing module that would allow ec2 instances to handle the fulfillment of the order. in the case of processing errors, the messages should be allowed to be re-processed at a later stage. the order processing system should be able to scale transparently without the need for any manual or programmatic provisioning of resources.