Architectural Design of a Deployment Platform to Provision Mixed-tenancy SaaS-Applications
Matthias Reinhardt, Stefan T. Ruehl, Stephan A. W. Verclas, Urs Andelfinger, Alois Schütte · 2014
Software-as-a-Service (SaaS) is a delivery model whose basic idea is to provide applications to the customer on demand over the Internet. In contrast to similar but older approaches, SaaS promotes multi-tenancy as a tool to exploit economies of scale. This means that a single application instance serves multiple customers. However, a major throwback of SaaS is the customers’ hesitation of sharing infrastructure, application code, or data with other tenants. This is due to the fact that one of the major threats of multi-tenancy is information disclosure due to a system malfunction, system error, or aggressive actions by individual users. So far the only approach in research to counteract on this hesitation has been to enhance the isolation between tenants using the same instance. Our approach (presented in earlier work) tackles this hesitation differently. It allows cus- tomers to choose if or even with whom they want to share the application. The approach enables the customer to make that choice not just for the entire application but specifically for individual application components and the underlaying infrastructure. This paper contributes to the mixed-tenancy approach by introducing a software pattern that allows to es- tablish communication between ACs that are deployed following the mixed-tenancy paradigm. The special challenges at this point are that, first, it shall be possible to migrate existing multi-tenancy applications into a mixed-tenancy environment, and secondly that constraints given by customers shall also be enforced for communication. The contributions of this paper are evaluated based on a representative example that employs all possible kinds of communication. For this it is necessary to present a prototypical implementation of a deployment platform that allows to deploy multi-tenancy applications following the mixed-tenancy paradigm automatically.