Towards flexible and reusable saas for multi-tenancy to design, implement and bind multi-functional variability for Rich-Variant services

Software-as-a-Service (SaaS) is a new delivery model, that involves providing applications to the customer on demand over the Internet. SaaS promotes multi-tenancy as a tool to exploit economies of scale. However, the flexibility of an application to be adapted to individual tenant´s needs is a major requirement. Thus, we initiate in this paper to an approach proposing a more flexible and reusable SaaS system for multi-tenancy. This approach consist on integrating a functional variability using Rich-Variant Components with a deployment variability enabling the customers to choose with which others tenants they want or don´t want to share instances. The approach presented enables exploiting the economies of scale while avoiding the problem of customers´ hesitation about sharing with other tenants.