Towards Reliable Multi-Tenant Software as-a Service Application

Software as a Service (SaaS) is a delivery model in which software applications are maintained and run by SaaS provider in in lieu of maintaining it at the client location. A multi-tenant SaaS application has various advantages including reduced software development time, reduced software maintenance cost and much more. The reliability of multi-tenant software application is the probability that the application functions fault-free as intended over a period of time. SaaS reliability is not a simple task due to the complexity of cloud resources and its massiveness. Moreover, the various types of failures in cloud computing are correlated to each another. Hence, applying existing reliability models in SaaS is challenging. One of the aspects for slow application migration to cloud is due to its reliability guarantee. Our proposed framework considers reliability of both design and operating stages of multi-tenant SaaS application. New application component instances are created based on the reliability and the security risk factor computed using component instance's specific factors. Additionally, the component instances are placed in diverse availability zones. The proposed reliability framework increases the availability of component instances and enhances security of the application. Our evaluation and discussions shows that the proposed approach enhances the reliability of SaaS application.