Engineering service level agreements as an integral part of software systems and their architectures

Service level agreements (SLA) for most software systems which are offered as services, are usually written in text form only. Thus, they are often fuzzy and not integrated with the system, i.e., the development activities and architecture are independent from the SLAs. Therefore, there is typically no transparency for service consumers regarding the actual service status, while service providers have no control over the system with respect to the SLAs or are dependent on experts. In this paper, we present a process for systematically integrating SLAs with an interoperable software system and its architecture. We propose a maturity model for SLA enforcement so that organizations can clearly see where they are with respect to SLA integration. Formalizing the SLAs with a Domain-Specific Language and establishing architecture-centric monitoring and analysis can contribute a lot to the enforcement of SLAs. We share our experiences and key takeaways for SMEs learned from an industrial case study. Our approach and the takeaways will help service providers to practically guarantee high quality of SLAs and will make the service providers more trustworthy.