Cloud-native deployments are typically ad-hoc and fragmented, leading to repeated misconfigurations and increased security risk. A challenge that arises often in modern deployment processes is the use of diverse heterogeneous technologies, such as Infrastructure-as-Code frameworks and cloud-specific tools. This causes a technological lock-in, making migration, adoption of alternative solutions, and supporting multi-cloud environments difficult. Another issue that further complicates current deployment processes is the collaboration of multiple actors during the process, such as developers, cloud architects, and business decision-makers whose roles are not well defined.To address these challenges, we advocate for a constraint-based approach of deployment. We emphasize security and compliance where constraints are declarative and treated as first-class inputs. This process would enable the specification of high-level constraints (e.g. security, cost, legal, etc.) and technical requirements in a unified and structured manner. This makes deployments portable across environments and cloud providers, auditable, and resilient to evolution. By introducing clear role separation and constraints validation, our approach promotes accountability while reducing the cognitive load on individual deployment actors.We propose a framework that enables actors involved in the deployment to specify constraints at various stages (architecture level, implementation level, etc.). These constraints are evaluated and verified by a constraint solver, and results into a set of feasible deployment options. Deployment scripts are generated from one of the feasible deployments in order to deploy the application. It is worth stressing that our intention is not to replace existing deployment workflows, but rather to provide a complementary approach.

In the context of complex system development, heterogeneous modeling responds to the need to integrate several domains. This need requires the use of the most appropriate formalism and tooling for each domain to be efficient. Model federation promotes the semantic interoperability of heterogeneous models by providing the means to reify correspondences between different model elements, add custom behaviors and bridge the gap between technological spaces. As such, it can be used as an infrastructure to address many different system engineering problems. This is what we have been doing for over a decade, as part of a close collaboration between a small software engineering startup and academia. This paper reports on this experience.