Declarative vs. Imperative: Two Modeling Patterns for the Automated Deployment of Applications

In the field of cloud computing, the automated deployment of applications is of vital importance and supported by diverse management technologies. However, currently there is no systematic knowledge collection that points out commonalities, capabilities, and differences of these approaches. This paper aims at identifying common modeling principles employed by technologies to create automatically executable models that describe the deployment of applications. We discuss two fundamental approaches for modeling the automated deployment of applications: imperative procedural models and declarative models. For these two approaches, we identified (i) basic pattern primitives and (ii) documented these approaches as patterns that point out frequently occurring problems in certain contexts including proven modeling solutions. The introduced patterns foster the understanding of common application deployment concepts, are validated regarding their occurrence in established state-of-the-art technologies, and enable the transfer of that knowledge.