The current cloud market is dominated by a few providers, which offer cloud services in a take-it-or-leave-it manner. However, the dynamism and uncertainty of cloud environments may require the change over time of both application requirements and service capabilities. The current service-level agreement (SLA) management solutions cannot easily guarantee a trustworthy, distributed SLA adaptation due to the centralized authority of the cloud provider who could also misbehave to pursue individual goals. To address the above issues, we propose a novel SLA management framework, which facilitates the specification and enforcement of dynamic SLAs that enable one to describe how, and under which conditions, the offered service level can change over time. The proposed framework relies on a two-level blockchain architecture. At the first level, the smart SLA is transformed into a smart contract that dynamically guides service provisioning. At the second level, a permissioned blockchain is built through a federation of monitoring entities to generate objective measurements for the smart SLA/contract assessment. The scalability of this permissioned blockchain is also thoroughly evaluated. The proposed framework enables creating open distributed clouds, which offer manageable and dynamic services, and facilitates cost reduction for cloud consumers, while it increases flexibility in resource management and trust in the offered cloud services.

中文翻译：

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使用智能合约和区块链进行分布式服务级别协议管理

当前的云市场由少数提供商主导，它们以接受或放弃的方式提供云服务。但是，云环境的动态性和不确定性可能需要应用程序需求和服务能力随时间发生变化。当前的服务级别协议 (SLA) 管理解决方案无法轻松保证可信赖的分布式 SLA 适应，因为云提供商的集中权限也可能为了追求个人目标而行为不端。为了解决上述问题，我们提出了一种新颖的 SLA 管理框架，它促进了动态 SLA 的规范和实施，使人们能够描述所提供的服务级别如何以及在何种条件下随时间变化。提议的框架依赖于两级区块链架构。在第一级，将智能 SLA 转化为动态指导服务提供的智能合约。在第二级，通过监控实体联盟构建许可区块链，为智能 SLA/合同评估生成客观测量值。该许可区块链的可扩展性也得到了彻底评估。提议的框架能够创建开放的分布式云，提供可管理的动态服务，并有助于降低云消费者的成本，同时提高资源管理的灵活性和对所提供云服务的信任。许可区块链是通过监控实体联盟构建的，以生成用于智能 SLA/合同评估的客观测量值。该许可区块链的可扩展性也得到了彻底评估。提议的框架能够创建开放的分布式云，提供可管理的动态服务，并有助于降低云消费者的成本，同时提高资源管理的灵活性和对所提供云服务的信任。许可区块链是通过监控实体联盟构建的，以生成用于智能 SLA/合同评估的客观测量值。该许可区块链的可扩展性也得到了彻底评估。提议的框架能够创建开放的分布式云，提供可管理的动态服务，并有助于降低云消费者的成本，同时提高资源管理的灵活性和对所提供云服务的信任。