An Infrastructure as a Service (IaaS) cloud provider is committed to each tenant by a service level agreement (SLA) which indicates the terms of commitment, e.g. the level of availability of the IaaS cloud service.The different resources providing this IaaS cloud service may need to be upgraded several times throughout their life-cycle; and these upgrades may affect the service delivered by the IaaS layer. This may violate the SLAs towards the tenants and result in penalty as they impact the tenant services relying on the IaaS.Therefore, it is important to handle upgrades properly with respect to the SLAs.The upgrade of IaaS cloud systems inherits all the challenges of clustered systems and faces other, cloud specific challenges, such as size and dynamicity due to elasticity.In this paper, we propose a novel approach to automatically upgrade an IaaS cloud system under SLA constraints such as availability and elasticity.In this approach, the upgrade methods and actions appropriate for each upgrade request are identified, scheduled, and applied automatically in an iterative manner based on the vendors descriptions of the infrastructure components, the tenant SLAs, and the status of the system. The proposed approach allows new upgrade requests during ongoing upgrades, which makes it suitable for continuous delivery.In addition, it also handles failures of upgrade actions through localized retry and undo operations automatically.
翻译:作为服务(IaaS)云提供商的一个基础设施,通过服务级协议(SLA)向每个承租人承诺向每个承租人提供云层服务,该服务级协议表明了承诺条件,例如IaAS云服务的供应水平。 提供IaAS云服务的不同资源可能需要在整个生命周期内进行数次升级;这些升级可能会影响IaAS层提供的服务,这可能违反服务级协议对租户提供的服务,并导致处罚,因为它们影响到依赖IaaAS的租户服务。 因此,必须适当处理服务级协议的升级。 IaS云系统的升级继承了集成系统的所有挑战,并面临其他具体的云层挑战,如由于弹性作用而产生的规模和动态。 在本文件中,我们提出了一种新颖的办法,在服务级协议的可用性和弹性等制约下自动升级一个IaAS云系统。