Software Architecture for the Cloud – A Roadmap Towards Control-Theoretic, Model-Based Cloud Architecture

Abstract

Abstract. The cloud is a distributed architecture providing resources as tiered services. Through the principles of service-orientation and generally provided using virtualisation, the deployment and provisioning of applications can be managed dynamically, resulting in cloud platforms and applications as interdependent adaptive systems. Dynamically adaptive systems require a representation of requirements as dynamically manageable models, enacted through a controller implementing a feedback look based on a control-theoretic framework. We argue that a controltheoretic, model-based architectural framework for the cloud is needed. While some critical aspects such as uncertainty have already been taken into account, what has not been accounted for are challenges resulting from the cloud architecture as a multi-tiered, distributed environment. We identify challenges and define a framework that aims at a better understanding and a roadmap towards control-theoretic, model-based cloud architecture -driven by software architecture concerns.

Fuzzy Self-Learning Controllers for Elasticity Management in Dynamic Cloud Architectures

“…Current solutions typically rely on threshold-based rules, offered by several commercial cloud providers/platforms such as Amazon EC2, Microsoft Azure and OpenStack. Best practice is to define a comprehensible set of scaling rules, assuming a linear and constant dependency between resource assignments and performance improvements, while in Internet scale applications, the complexity of application architecture, the interferences among components and the frequency by which hardware and software failure happen typically invalidate the assumptions [11], calling for new approaches [23], [8].…”

Engineering Cloud-Based Applications: Towards an Application Lifecycle

“…are necessary to deal with the multi-tenancy induced performance variability and its impact to the QoS of cloud-based applications. The introduction of a MAPE-K (Monitor, Analyse, Plan, and Execute over a Knowledge base) feedback loop [20] is a necessary and very common solution at this level as the means to implement control [29], but the difficulty is in evaluating the impact of individual cloud services, e.g. a DBaaS solution, to overall performance.…”

Cloud architecture continuity: Change models and change rules for sustainable cloud software architectures

“…6,7 Architecture continuity for cloud systems needs a solution that considers uncertainties at different levels: not only uncertainty related to infrastructure and resources but also uncertainty arising from the presence of multiple actors, distribution, and heterogeneity. 8,9 Specific to the cloud as a virtualised environment is the opportunity to consider resources, ie, the platform on which a software application runs, in decisions about its design architecture and changes to its initial design overtime. This paper contributes with a set of models and rules for managing change to support cloud software architecture continuity.…”