Automatic deployment of an information technology (TT) system instance having hardware and software components. An application model of the software components is generated based on use cases and is associated with functional and non-functional requirements. An infrastructure model of the hardware components is generated based on the application model. The same software component modeling language represents both the application and infrastructure models. A markup language computer file is generated to include a design of the IT system instance and instructions for accessing library-stored assets that specify the hardware and software components. The computer file is exported to a deployment tool for automatic deployment of the IT system instance based on carrying out the instructions. In one embodiment, the impact of a proposed change is identified and managed in real time prior to a deployment of the proposed change.