Formulating Criticality-Based Cost-Effective Fault Tolerance Strategies for Multi-Tenant Service-Based Systems

The proliferation of cloud computing has fueled the rapid growth of multi-tenant service-based systems (SBSs), which serve multiple tenants simultaneously by composing existing services in the form of business processes. In a distributed and volatile operating environment, runtime anomalies may occur to the component services of an SBS and cause end-to-end quality violations. Engineering multi-tenant SBSs that can quickly handle runtime anomalies cost effectively has become a significant challenge. Different approaches have been proposed to formulate fault tolerance strategies for engineering SBSs. However, none of the existing approaches has sufficiently considered the service criticality based on multi-tenancy where multiple tenants share the same SBS instance with different multi-dimensional quality preferences. In this paper, we propose Criticality-based Fault Tolerance for Multi-Tenant SBSs (CFT4MTS), a novel approach that formulates cost-effective fault tolerance strategies for multi-tenant SBSs by providing redundancy for the critical component services. First, the criticality of each component service is evaluated based on its multi-dimensional quality and multiple tenants sharing the component service with differentiated quality preferences. Then, the fault tolerance problem is modelled as an Integer Programming problem to identify the optimal fault tolerance strategy. The experimental results show that, compared with three existing representative approaches, CFT4MTS can alleviate degradation in the quality of multi-tenant SBSs in a much more effective and efficient way.