Declarative Modeling for Cloud Deployments

Cloud compung offers several benefits: resources can be allocated on demand, scaling according to varying usage paerns and eventually reducing the costs for individual groups to provision and maintain their own infrastructure. Providing cloud compung services besides connecvity is a natural evoluon for NRENs as users demand such services and also because the networking infrastructure itself is evolving towards using virtualizaon techniques. Building a cloud plaorm is though a daunng task, that requires coordinang the deployment of many services, interrelated and dependent on each other. Provisioning, servicing and maintaining the plaorm should be automated. For the deployment of the GARR Federated Cloud Compung Plaorm, we chose an intent‑based approach, which relies on declarave modeling for specifying the requirements of the service provisioning, describing the parts that compose the system, any specific constraint requirements and the supplier/consumer relaons between them. An automated orchestraon tool analyzes the model, compares it with the current state of the system being deployed, determines the resources that need to be provisioned, generates a sequence of executable steps needed to bring the deployment in line with the model, and coordinate