Variability in Multi-tenant Environments: Architectural Design Patterns from Industry

In order to serve a lot of different customers in a SaaS environment, software vendors have to comply to a range of different varying requirements in their software product. Because of these varying requirements and the large number of customers, a variable multi-tenant solution is needed to achieve this goal. This paper gives a pragmatic approach to the concepts of multi-tenancy and variability in SaaS environments and proposes three architectural patterns that support variability in multi-tenant SaaS environments. The Customizable Data Views pattern, the Module Dependent Menu pattern and the Pre/Post Update Hooks pattern are explained and shown as good practices for applying variability in a multi-tenant SaaS environment. All patterns are based on case studies performed at two large software vendors in the Netherlands who are offering an ERP software product as a service.