Saline: Improving Best-Effort Job Management in Grids

Although virtualization technologies have recently gained a lot of interest in Grid computing as they allow flexible resource management, the most common way to exploit grids still relies on dedicated services like resource management systems (RMSs) to get resources at a particular time. To improve resource usage, most of these systems provide a best-effort mode where lowest priority jobs can be executed when resources are idle. This particular mode does not provide any guarantee of service and jobs may be killed at any time by the RMS when the nodes they use are subject to higher priority reservations. This behaviour potentially leads to a huge waste of computation time or at least requires users to deal with checkpoints of their best-effort jobs. In this paper, we present Saline, a generic and non-intrusive framework to manage best-effort jobs at grid level through virtual machines (VMs) usage. We discuss the main challenges concerning the design of such a grid system, focusing on VM snapshot management and network configuration. Results of preliminary experiments show the interest of our proposal to ensure an efficient execution of best-effort jobs through the whole grid

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

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

Saline: Improving Best-Effort Job Management in Grids

Although virtualization technologies have recently gained a lot of interest in Grid computing as they allow flexible resource management, the most common way to exploit grids still relies on dedicated services like resource management systems (RMSs) to get resources at a particular time. To improve resource usage, most of these systems provide a best-effort mode where lowest priority jobs can be executed when resources are idle. This particular mode does not provide any guarantee of service and jobs may be killed at any time by the RMS when the nodes they use are subject to higher priority reservations. This behaviour potentially leads to a huge waste of computation time or at least requires users to deal with checkpoints of their best-effort jobs. In this paper, we present Saline, a generic and non-intrusive framework to manage best-effort jobs at grid level through virtual machines (VMs) usage. We discuss the main challenges concerning the design of such a grid system, focusing on VM snapshot management and network configuration. Results of preliminary experiments show the interest of our proposal to ensure an efficient execution of best-effort jobs through the whole grid

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

Observation of HandiMathKey appropriation phase by disabled students in a middle school

The mathematical input in text editors by disabled students is demanding both at the functional level (motor disorder) and at the cognitive level (attention, visual-spatial, memory) and generates fatigability little productive and effective gain. To reduce these demands, HandiMathKey, a mathematical keyboard software was designed by applying a usercentered method. The aim of paper is to report how different disabled students have appropriated HandiMathKey in a middle school by an observation carried out by a multidisciplinary team. The hypothesis is that HandiMathKey can be learned and used by all students with disabilities

Modalites d'elaboration de la biomasse aerienne par des repousses de ray-grass anglais (Lolium perenne L.) et de fetuque elevee (Festuca arundinacea Schreb.). Effets du stade d'interruption de la croissance printaniere

SIGLEINIST T 73699 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Flexibilité dans la gestion des infrastructures informatiques distribuées

Cette thèse s'intéresse à la flexibilité dans les infrastructures informatiques distribuées du point de vue de leurs administrateurs et utilisateurs. Pour les utilisateurs, il s'agit de trouver au moment où ils en ont besoin des ressources matérielles adaptées avec un environnement personnalisé à l'exécution de leur application. Pour les administrateurs, il s'agit de définir les politiques d'allocation des ressources (politiques d'usage et de sécurité) pour les applications des utilisateurs. Nous avons étudié la problématique de la flexibilité dans le contexte des grilles et des centrales numériques (CN). Tout d'abord, nous avons conçu et mis en oeuvre le système Saline qui s'appuie sur la virtualisation pour permettre l'exécution de tout type de tâche en mode préemptif dans les grilles. Nous avons également proposé le système Grillade qui combine les mécanismes de flexibilité offerts par les grilles et les CN pour d'une part, étendre dynamiquement une grille avec des ressources virtuelles fournies par des CN et d'autre part, construire des nuages de type IaaS fédérant les ressources de plusieurs sites. Grillade étend le système de grille XtreemOS. Il permet en outre grâce à la technologie de système à image unique de proposer aux utilisateurs des machines virtuelles exécutées sur une agrégation de nœuds. Enfin, nous proposons un formalisme permettant de classer les systèmes de gestion de ressources offrant de la flexibilité et de définir des règles pour les combiner. Le système Tropicbird qui s'appuie sur ce formalisme met en œuvre, à la demande, des plates-formes virtuelles spécifiées par les utilisateurs sur une infrastructure matérielle.This thesis focuses on flexibility in distributed IT infrastructure for administrators and users. From users point of view, they need on-demand resources fitting their application needs. For administrators, they set policies for resource allocation (policies for resource usage and safety) in order to meet the user application needs. We studied the issue of flexibility in the context of grids and clouds. First, we designed and implemented the Saline system. Saline is based on virtualization technology for the execution of besteffort jobs in grids. We also proposed the Grillade system which combines flexibility mechanisms provided by grids and clouds. This allow, firstly, to dynamically extend a grid with virtual resources provided by a cloud and secondly, to build IaaS clouds by federating resources provided by multiple sites. Grillade extends the XtreemOS grid system. It also allows to use single system image technology to provide to users virtual machines run on an aggregation of nodes. Finally, we propose a formalism to classify the resource management systems and to provide flexibility to define rules for combining them. Tropicbird system, based on this formalism, implements on-demand virtual platforms specified by users on the physical infrastructure.RENNES1-BU Sciences Philo (352382102) / SudocSudocFranceF

Complementarity Between Virtualization and Single System Image Technologies ⋆

Abstract. Nowadays, the use of clusters in research centers or industries is undeniable. Since few years, the usage of virtual machines (VM) offers 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 single system image (SSI) technologies are now deprecated, without considering some complementarities between VMs and SSI technologies are possible. After evaluating different configurations, we show that combining both approaches allows us to better address cluster challenges such as flexibility for the usage of available resources and simplicity of use. In other terms, the study shows that VMs add a level of management flexibility between the hardware and the application, whereas, SSIs give an abstraction of the distributed resources. The simultaneous usage of both technologies could improve the overall platform resources utilization, the cluster productivity and the efficiency of the running applications. Key words: cluster, virtualization, SSI, resource management.