No abstract

Today, traded cloud services are described by service level agreements that specify the obligations of providers such as availability or reliability. Violations of service level agreements lead to penalty payments. The recent development of prominent cloud platforms such as the re-design of Amazon's spot marketspace underpins a trend towards dynamic cloud markets where consumers migrate their services continuously to different marketspaces and providers to reach a cost-optimum. This leads to a heterogeneous IT infrastructure and consequently aggravates the monitoring of the delivered service quality. Hence, there is a need for a transparent penalty management system, which ensures that consumers automatically get penalty payments from providers in case of service violations. \newline In the paper at hand, we present a cloud monitoring system that is able to execute penalty payments autonomously. In this regard, we apply smart contracts hosted on blockchains, which continuously monitor cloud services and trigger penalty payments to consumers in case of service violations. For justification and evaluation we implement our approach by the IBM Hyperledger Fabric framework and create a use case with Amazon's cloud services as well as Azures cloud services to illustrate the universal design of the presented mechanism.