The Shape of Your Cloud: How to Design and Run Polylithic Cloud Applications

Nowadays the major trend in IT dictates deploying applications in the cloud, cutting the monolithic software into small, easily manageable and developable components, and running them in a microservice scheme. With these choices come the questions: which cloud service types to choose from the several available options, and how to distribute the monolith in order to best resonate with the selected cloud features. We propose a model that presents monolithic applications in a novel way and focuses on key properties that are crucial in the development of cloud-native applications. The model focuses on the organization of scaling units, and it accounts for the cost of provisioned resources in scale-out periods and invocation delays among the application components. We analyze dis-aggregated monolithic applications that are deployed in the cloud, offering both Container-as-a-Service (CaaS) and Function-as-a-Service (FaaS) platforms. We showcase the efficiency of our proposed optimization solution by presenting the reduction in operation costs as an illustrative example. We propose to group similarly low scale components together in CaaS, while running dynamically scaled components in FaaS. By doing so, the price is decreased as unnecessary memory provisioning is eliminated, while application response time does not show any degradation.