Design and Evaluation of a Virtual Experimental Environment for Distributed Systems

International audienceBetween simulation and experiments on real-scale testbeds, the combined use of emulation and virtualization provide a useful alternative for performing experiments on distributed systems such as clusters, grids, cloud computing or P2P systems. In this paper, we present Distem, a software tool to build distributed virtual experimental environments. Using an homogenenous set of nodes, Distem emulates a platform composed of heterogeneous nodes (in terms of number and performance of CPU cores), connected to a virtual network described using a realistic topology model. Distem relies on LXC, a low-overhead container-based virtualization solution, to achieve scalability and enable experiments with thousands of virtual nodes. Distem provides a set of user interfaces to accomodate different needs (command-line for interactive use, Ruby and REST APIs), is freely available and well documented. After a detailed description of Distem, we perform an experimental evaluation of several of its features.Entre la simulation et l'expérimentation sur des plates-formes réelles, l'usage combiné de l'émulation et de la virtualisation fournit une alternative utile pour réaliser des expériences sur des systèmes distribués tels que les clusters, grilles, le Cloud ou les systèmes P2P. Dans cet article, nous présentons Distem, un logiciel permettant de construire des environnements expérimentaux distribués virtuels. À partir d'un ensemble homogène de noeuds, Distem émule une plate-forme composée de noeuds hétérogènes (en termes de nombre et de performance de leurs coeurs CPU), connectés à un réseau virtuel décrit à partir d'un modèle de topologies réaliste. Distem se base sur LXC, une solution de virtualisation légère à base de conteneurs, pour obtenir des propriétés de passage à l'échelle satisfaisantes et permettre des expériences avec des milliers de noeuds virtuels. Distem fournit plusieurs interfaces utilisateurs permettant de s'adapter à différents besoins (ligne de commande pour l'usage interactif, Ruby, API REST), est librement disponible et bien documenté. Après une description détaillée de Distem, cet article présente une validation expérimentale de plusieurs de ses fonctionnalités

Porting the Distem Emulator to the CloudLab and Chameleon testbeds

The Distem emulator was designed in the context of the Grid'5000testbed. In this paper, we describe the experience of porting Distem totwo testbeds: CloudLab and Chameleon, in order to uncover possibleissues when deploying Distem on platforms different from Grid'5000. Italso provides some insight on differences between the design of each ofthose three testbeds, and their impact on experimenters

Testbeds in Computer Science

International audienceComputer scientists working on the design of hardware and software architectures and in particular on the design of distributed architectures (network, high performance computing, cloud, sensor networks, IoT, etc.) need to evaluate the relevance of their proposal at scale on a regular basis. Hence, their practice relies on frequent experimental evaluations, which leads to specific needs in term of experimental control. In this context, reproducing the work of other colleagues happens to be very difficult as it requires not only to have precise information about experimental conditions (software stack, external load, hardware type and configuration, etc.) but also to have a testbed allowing to recreate similar experimental conditions. A few experimental testbeds allowing for fine-grain experimental control have been built in the last decade (Grid5000, R2Lab, …). Such testbeds are mutualized and generally open-access, which makes it possible to compare in a fair and truthful way alternative approaches at large scale. In this webinar, Lucas Nussbaum will provide an overview of these projects and of their internals

Scaling your experiments

National audienceThere is a wide range of options to experiment on distributed systems and networking. Simulators running on a laptop or self-made testbeds are sometimes enough, but our field usually targets large to very large systems with potentially millions or billions of elements. In such a case, relying on a laptop or a self-made testbed is impossible. To scale up our experimental research, we can rely on larger-scale infrastructures and testbeds.In a first part, this talk will provide an overview of the landscape of infrastructures and testbeds supporting experimental research in distributed systems and networking.In a second part, we will focus on SDN/NFV experimentation, and will provide some feedback about the current state of available experimentation tools targeting large scale systems

Lincoln's Speeches Reconsidered

Originally published in 2005. Throughout the fractious years of the mid-nineteenth century, Abraham Lincoln's speeches imparted reason and guidance to a troubled nation. Lincoln's words were never universally praised. But they resonated with fellow legislators and the public, especially when he spoke on such volatile subjects as mob rule, temperance, the Mexican War, slavery and its expansion, and the justice of a war for freedom and union.In this close examination, John Channing Briggs reveals how the process of studying, writing, and delivering speeches helped Lincoln develop the ideas with which he would so profoundly change history. Briggs follows Lincoln's thought process through a careful chronological reading of his oratory, ranging from Lincoln's 1838 speech to the Springfield Lyceum to his second inaugural address.Recalling David Herbert Donald's celebrated revisionist essays (Lincoln Reconsidered, 1947), Briggs's study provides students of Lincoln with new insight into his words, intentions, and image

The History of Sir George Ellison

The History of Sir George Ellison (1766) is an important novel, both utopian and dystopian. Sir George, a man of benevolence, follows the pattern of the female utopia set forth in Scott\u27s first novel, A Description of Millenium Hall (1762). In this sequel, Scott addresses issues of slavery, marriage, education, law and social justice, class pretensions, and the position of women in society, consistently emphasizing the importance, for both genders and all classes and ages, of devoting one\u27s life to meaningful work. Although she adopted a gradualist approach to reform, Scott\u27s uncompromising revelation of the corruption of English society in her day is clear-sighted, arresting, and hard-hitting. A striking example of both the reformist aspirations of sensibility and the political ambitions of women writers during the mid-century. -- British Journal for Eighteenth-Century Studies Fill(s) a genuine need among scholars and students interested in early British women novelists. -- Kritikon Litterarum Although Scott is largely unknown today, her writing was well received in its time and understandably so. Her voice is amiable and articulate, and, though sticking to popular 18th-century devices and a ladylike tone, she takes on provocative topics. . . . Today\u27s readers will be struck by her conviction and relevance. -- Publishers Weekly Offers the best biographical information hitherto published on Scott. -- Utopian Studies The issues of slavery, female education, and marriage make it of interest to cultural critics. -- Wordsworth Circlehttps://uknowledge.uky.edu/upk_english_language_and_literature_british_isles/1011/thumbnail.jp