Smart Contracts in Cloud Computing
Smart contracts and blockchain have the potential to change the current shape of cloud markets by enabling the development of completely decentralised cloud/fog solutions, which lower costs and enforce predictable results without requiring any intermediary. In this paper, we survey three of these solutions, namely Golem, iExec and SONM, compare them and identify some of the problems they leave unsolved. Moreover, we consider existing standards for the development of interoperable decentralised cloud solutions that would allow such systems to compete with large providers and would prevent vendor lock-in. We believe that our study contributes to the evolution of cloud systems not only by pointing out incompatibilities among projects and possible solutions for research problems in the area, but also by reviewing the existing standards and suggesting new standardisation opportunities.
In this paper, we introduce SLAC, a SLA definition language specifically devised for clouds as a formalism to support the whole SLA lifecycle. The main novelty of the language is the possibility of capturing within the SLA the dynamic aspects of the environment by defining the conditions and actions to change service levels at runtime. SLAC permits to make the most of cloud elasticity, reduces the need for renegotiation and provides guarantees for dynamic scenarios. The language has formal syntax and semantics, and it comes with effective software tools supporting the whole SLA management lifecycle. The impact of our language and of its software tools is assessed by considering a series of experiments that provide empirical evidences of the advantages of SLAC.