An Extended Orthogonal Variability Model for Metadata-Driven Multitenant Cloud Services

A metadata-driven architecture for multitenant cloud services is an important class of cloud computing architectures. It enables dynamic variability of services on a single instance for embracing diverse requirements among multiple tenants. It does not require to develop applications, but to generate applications through metadata Web APIs at runtime according to individual tenant's requirements. The variability among requirements makes the design of multitenant services complicated. To design the variability of multitenant services, this article proposed an extended model of OVM (Orthogonal Variability Model) to model variability and their dependencies at two levels: meta-level and base-level. We demonstrate the effectiveness of the extended OVM through a case study of the development of an application service on Force. com from Salesforce.com.