Hosting and Using Services with QoS Guarantee in Self-adaptive Service Systems

Abstract. In service-oriented computing, the vision is a market of services with alternative providers offering the same services with different cost and quality of service (QoS) properties, where applications form and adapt dynamically through dynamic service discovery and binding. To ensure decent and stable QoS to end users and efficient use of resources, it is required that both client applications and service implementations are able to adapt both their internal configuration and their binding to other actors in response to changes in the environment. To this end, service level negotiation and agreements (SLA) are important to ensure coordinated end to end adaptation. In this paper we propose a solution based on the integration of an SLA mechanism into a compositional adaptation planning framework and describe a simple yet powerful implementation targeted for resource constrained mobile devices. As validation we include a case study based on a peer-to-peer distributed mobile application

Power Budgeting of Big Data Applications in Container-based Clusters

[Abstract] Energy consumption is currently highly regarded on computing systems for many reasons, such as improving the environmental impact and reducing operational costs considering the rising price of energy. Previous works have analysed how to improve energy efficiency from the entire infrastructure down to individual computing instances (e.g., virtual machines). However, the research is more scarce when it comes to controlling energy consumption, specially in real time and at the software level. This paper presents a platform that manages a power budget to cap the energy consumed from users to applications and down to individual instances. Using containers as virtualization technology, the energy limitation is implemented thanks to the platform's ability to monitor container energy consumption and dynamically adjust its CPU resources via vertical scaling as required. Representative Big Data applications have been deployed on the platform to prove the feasibility of this approach for energy control, showing that it is possible to distribute and enforce a power budget among users and applications.Ministerio de Ciencia e Innovación de España; TIN2016-75845-PMinisterio de Ciencia e Innovación de España; PID2019-104184RB-I00Consolidation Program of Competitive Reference Groups; ED431C 2017/04Xunta de Galicia e fondos FEDER; ED431G 2019/0

A review of energy measurement approaches

International audienceReducing the energy footprint of digital devices and software is a task challenging the research in Green IT. Researches have proposed approaches for energy management, ranging from reducing usage of software and hardware, compilators optimization, to server consolidation and software migration. However, optimizing the energy consumption requires knowledge of that said consumption. In particular, measuring the energy consumption of hardware and software is an important requirement for efficient energy strategies. In this review, we outline the different categories of approaches in energy measurements, and provide insights into example of each category. We draw recommendations from our review on requirements on how to efficiently measure energy consumption of devices and software

A Component-based Approach to Compose Transaction Standards

International audienceThis paper tackles the problem of composition of transaction services, which are governed by various transaction standards. Among others, we can cite the Object Transaction Service, Java Transaction Service, or Web Services Atomic Transaction. However, the Web Services Atomic Transaction standard encloses legacy transaction standards to support the Web Services application platform. This encapsulation introduces an additional complexity to the system and hides the specificities of legacy transaction standards. When composing heterogeneous legacy applications, the underlying transaction services are basically not composed transparently. This paper presents an approach to build an Adapted Transaction Service, named ATS, which supports several transaction standards concurrently. The objective of ATS is to facilitate the transaction standards composition. To introduce ATS we detail how the Object Transaction Service, Web Services Atomic Transaction, and Java Transaction Service standards can be composed. Besides, an ATS implementation is introduced using the GoTM framework. We show that this fine-grained component-based approach does not introduce an additional overhead to legacy applications and supports well scalability. Moreover, this approach can be extended to other standards

Context-Aware Adaptive Services: The PLASTIC Approach

Abstract. The near future envisions a pervasive heterogeneous computing infrastructure that makes it possible for mobile users to run software services on a variety of devices, from networks of devices to stand-alone wireless resource-constrained ones. To ensure that users meet their non-functional requirements by experiencing the best Quality of Service according to their needs and specific contexts of use, services need to be context-aware and adaptable. The development and the ex-ecution of such services is a big challenge and it is far to be solved. In this paper we present our experience in this direction by describing our approach to context-aware adaptive services within the IST PLASTIC project. The approach makes use of Chameleon, a formal framework for adaptive Java applications.