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Cloud computing is a successful model for hosting webfacing applications that are accessed by their users as services. While clouds currently offer Service Level Agreements (SLAs) containing guarantees of availability, they do not make performance guarantees for deployed applications.In this work we present Cerebro -a system for establishing statistical guarantees of application response time in cloud settings. Cerebro combines off-line static analysis of application control structure with on-line cloud performance monitoring and statistical forecasting to predict bounds on the response time of web-facing application programming interfaces (APIs). Because Cerebro does not require application instrumentation or per-application cloud benchmarking, it does not impose any runtime overhead, and is suitable for use at cloud scales. Also, because the bounds are statistical, they are appropriate for use as the basis for SLAs between cloud-hosted applications and their users.We investigate the correctness of Cerebro predictions, the tightness of their bounds, and the duration over which the bounds persist in both Google App Engine and AppScale (public and private cloud platforms respectively). We also detail the effectiveness of our SLA prediction methodology compared to other performance bound estimation methods based on simple statistical analysis.

Abstract-To track, control, and compel reuse of web APIs, we investigate a new approach to API governance -combined policy, implementation, and deployment control of web APIs. Our approach, called EAGER, provides a software architecture that integrates into PaaS platforms to support systemwide, deployment-time enforcement of governance policies. Specifically, EAGER checks for and prevents backward incompatible API changes from being deployed into production PaaS clouds, enforces service reuse, and facilitates enforcement of other best practices in software maintenance via policies. Our experiments with an EAGER prototype show that enforcing API governance at deployment-time in PaaS clouds is efficient and scalable to thousands of APIs and policies.

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As scalable information technology evolves to a more cloud-like model, digital assets (code, data and software environments) increasingly require curation as web-accessible services. "Service-izing" digital assets consists of encapsulating assets in software that exposes them to web and mobile applications via well-defined yet flexible, network accessible, application programming interfaces (APIs). In this paper, we postulate that recent advances in cloud computing make cloud platforms as-aservice (PaaS) ideal for deployment, lifecycle management, and policy-based control -i.e. API governance -for extant and future digital assets. Toward this end, we overview API governance as a PaaS technology and outline some early results generated by our investigation of a prototype we are developing, called EAGER, for implementing API governance at scale.