Dynamic Streams for Efficient Communications Between Migrating Processes in a Cluster

This paper presents a communication system designed to allow efficient process migration in a cluster. The proposed system is generic enough to allow the migration of any kind of stream: socket, pipe, char devices. Communicating processes using IP or Unix sockets are transparently migrated with our mechanisms and they can still efficiently communicate after migration. The designed communication system is implemented as part of Kerrighed, a single system image operating system for a cluster based on Linux. Preliminary performance results are presented

Nu@ge: Towards a solidary and responsible cloud computing service

Best Paper AwardInternational audienceThe adoption of cloud computing is still limited by several legal concerns from companies. One of those reasons is the data sovereignty, as data can be physically host in sensible locations, resulting in a lack of control for companies. In this paper, we present the Nu@ge project aimed at building a federation of container-sized datacenter on the French territory. Nu@ge provides a software stack that enables companies to put independent datacenters in cooperation in a national mesh. Additionally, a prototype of a container-sized datacenter has been validated and patented

OpenMosix, OpenSSI and Kerrighed: A Comparative Study

This paper presents a comparative study of Kerrighed, openMosix and OpenSSI, three Single System Image (SSI) operating systems for clusters. This experimental study gives an overview of SSI features offered by these SSI and evaluates performance of such features

Is Virtualization Killing Single System Image Research?

Nowadays, use of clusters in research centers or industries is undeniable. Cluster usage is typically based on two different models: (i) batch schedulers and (ii) single system image (SSI). In the first case, applications are scheduled by a ``supervisor'', the batch scheduler, according to cluster resources availability. In the second case, an SSI operating system (OS) gives the illusion that a distributed system is a standard SMP machine, allowing users to use standard UNIX tools to manage their applications. Even if SSI solutions are usually more complete in terms of functionality, batch schedulers are usually preferred because of their simplicity in term of both configuration and usage. Moreover, since few years, combining virtual machines and batch systems offer more advanced resource management capabilities, using features such as virtual machine live migration. Because of the latest contributions in the domain, some may argue that SSI technologies are now deprecated. In this paper, we analyze whether virtualization technologies will surpass the SSI approach, or if these two models are not contradictory but complementary. In fact, after evaluating different configurations, we show that by combining both approaches, we can improve several aspects associated to application computation such as flexibility of administration, simplicity of use, security and portability

A Multidisciplinary Airplane Research Integrated Library With Applications To Partial Turboelectric Propulsion

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Novel Insights into the Bovine Polled Phenotype and Horn Ontogenesis in Bovidae

Despite massive research efforts, the molecular etiology of bovine polledness and the developmental pathways involved in horn ontogenesis are still poorly understood. In a recent article, we provided evidence for the existence of at least two different alleles at the Polled locus and identified candidate mutations for each of them. None of these mutations was located in known coding or regulatory regions, thus adding to the complexity of understanding the molecular basis of polledness. We confirm previous results here and exhaustively identify the causative mutation for the Celtic allele (PC) and four candidate mutations for the Friesian allele (PF). We describe a previously unreported eyelash-and-eyelid phenotype associated with regular polledness, and present unique histological and gene expression data on bovine horn bud differentiation in fetuses affected by three different horn defect syndromes, as well as in wild-type controls. We propose the ectopic expression of a lincRNA in PC/p horn buds as a probable cause of horn bud agenesis. In addition, we provide evidence for an involvement of OLIG2, FOXL2 and RXFP2 in horn bud differentiation, and draw a first link between bovine, ovine and caprine Polled loci. Our results represent a first and important step in understanding the genetic pathways and key process involved in horn bud differentiation in Bovidae

Conception d'un service de communication pour systèmes d'exploitation distribués pour grappes de calculateurs: mise en oeuvre dans le système à image unique Kerrighed

This thesis presents the design of a communication service dedicated to the Single System Image architecture in the clusters system field.The first problem is to design a communication model that fits, as efficient as possible, kernel to kernel communications needs. The idea of 'communication transaction' has been proposed in order to describe the content of a message and to describe actions upon this message.In a SSI, a global scheduler may move a running process from a node to another one. Our second contribution concerns the design of a communication layer helping in the migration of process communication by streams (socket, pipe, etc.). Dynamic streams are mechanisms allowing to move the extremity of a stream without any performance lost.This communication service has been developped in the Kerrighed SSI. The prototype has been proved with industrial MPI applications (without any modifications of the application or the middleware).Dans la ligné des réseaux de stations de travail, les grappes de calculateurs représentent une alternative attrayante, en terme de performance et de coût, comparativement aux machines parallèles traditionnelles, pour l'exécution d'applications parallèles de calcul à haute performance. Une grappe de calculateurs est constituée d'un ensemble de noeuds interconnectés par un réseau dédié à haute performance. Les systèmes à image unique (Single System Image -- SSI) forment une classe de logiciel offrant aux utilisateurs et programmeurs d'une grappe de calculateurs, l'illusion d'une machine unique. Un SSI peut être conçu à différents niveaux (intergiciel, système d'exploitation) selon le degré d'exigence quant à laréutilisation sans modification de modèles de programmation et d'applications existants. Dans notre contexte, les applications visées sont de type MPI ou OpenMP. Comme pour tout système distribué, le système d'interconnexion des noeuds de la grappe se trouve au coeur des performances globales de la grappe et des SSIs.Les travaux présentés dans cette thèse portent sur la conception d'un système de communication dédié aux systèmes d'exploitation distribués pour grappes. Ces travaux s'inscrivent dans le cadre de la conception et la réalisation d'un SSI pour l'exécution d'applications haute performance sur grappe de calculateurs.Notre première contribution se situe dans la conception d'un modèle de communication adapté aux communications internes aux services systèmes distribués qui constituent le SSI. En effet, de la performance des communications dépendent les performances globales de la grappe. Les transactions de communication permettent (i) de décrire un message lors de sa création, (ii) d'acheminer efficacement le message enfontion des ressources disponibles, et (iii) de délivrer et traiter lemessage au plus tôt sur le noeud destinataire.Notre seconde contribution correspond à la conception d'un support au déplacement de processus communiquant par flux de données (socket, pipe, etc.). En effet, au sein d'un SSI, les processus peuvent être déplacés en cours d'exécution par un ordonnanceur global. Les flux dynamiques permettent le déplacement d'une extrémité de communication sans dégradation des performances.Nos propositions ont été mises en oeuvre dans le prototype de SSI Kerrighed, conçu au sein du projet INRIA PARIS de l'IRISA. Ce prototype nous a permis d'évaluer le système de communication proposé. Nous avons montré une réactivité accrue des services systémes distribués ainsi qu'une absence de dégradation des performances des applications communiquant par messages (en particulier MPI) aprés déplacement d'un processus. L'ensemble de ce travail est distribué sous licence GPL en tant que partie de Kerrighed et est disponible à l'adresse: http://www.kerrighed.org

Refinement Proposal of the Goldberg's Theory

International audienceVirtual Machines (VM) allow the execution of various operating systems. VM mechanisms provide several functionalities which are nowadays strongly appreciated by developers and administrators (isolation between applications, flexibility of resource management...). So, “virtualization” has become a buzz word and a lot of “virtualization” solutions have been proposed, each providing particular functionalities. Goldberg proposed to classify virtualization techniques in two models (Type-I and Type-II), which does not enable the classification of latest “virtualization” technologies such emulation, partitioning... We propose an extension of the Goldberg model in order to take into account latest “virtualization” mechanisms. After giving general definitions, we show how our proposal enables to rigorously formalize the following terms: virtualization, emulation, abstraction, partitioning, and identity. We show that a single virtualization solution is generally composed by several layers of virtualization capabilities, depending on the granularity of the analysis. In this manner, our model allow us to classify virtualization technologies according to their performance, similarity and portability

Dynamic Resource Management in a Cluster for High-Availability

In order to execute high performance applications on a cluster, it is highly desirable to provide distributed services that globally manage physical resources distributed over the cluster nodes. However, as a distributed service may use resources located on dierent nodes, it becomes sensitive to changes in the cluster con guration due to node addition, reboot or failure. In this paper, we propose a generic service performing dynamic resource management in a cluster in order to provide distributed services with high availability. This service has been implemented in the Gobelins cluster operating system. The dynamic resource management service we propose makes node addition and reboot nearly transparent to all distributed services of Gobelins and, as a consequence, fully transparent to applications. In the event of a node failure, applications using resources located on the failed node need to be restarted from a previously saved checkpoint but the availability of the cluster operating system is guaranteed, provided that its distributed services implement recon guration features