Toward Realization of Deployment Variability for Software-as-a-Service Applications

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. On the one hand, however, a major throwback of SaaS is the customers´ hesitation of sharing infrastructure, application code, or data with other tenants. On the other hand, tenants might specifically demand to share the same application code or data in order to be able to collaborate, e.g. joint product development or joint sales activities for their complementing products. In this paper an approach is presented which strives for enabling the customers 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 (AC). Thus, it is possible that a customer chooses to have their application deployed publicly (sharing the application with all other customers choosing this model) except for one or more ACs which handle very sensitive data. For these ACs, the customer may demand not to share at all, not to share with competitors, or even specifically name with which other customers they wish to share infrastructure.