Author: "Guillaume, Pierre" / Topic: business.industry - Searchworks@Jio Institute Digital Library Search Results

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1. Ectopic cilia in 112 dogs: A multicenter retrospective study

Author: Guillaume Cazalot, Matthieu Crémoux, Iona Mathieson, Anne-Sophie Poinsard, Julien Charron, Jean-Yves Douet, Jean-Baptiste Barbry, Charles Cassagnes, Sylvain Medan, Anne-Maïmiti Dulaurent, Olivier Balland, Thomas Dulaurent, Frédéric Goulle, Pierre-François Isard, Guillaume-Pierre Mias, Julien Michel, and Charlotte Barbé
Subjects: Male, medicine.medical_specialty, Conjunctiva, genetic structures, biology.animal_breed, French bulldog, Keratitis, Dogs, medicine, Animals, Cilia, Dog Diseases, Corneal Ulcer, Retrospective Studies, General Veterinary, biology, business.industry, Retrospective cohort study, medicine.disease, corneal ulcer, Hair follicle, eye diseases, Surgery, medicine.anatomical_structure, Granuloma, Female, sense organs, Eyelid, business
Abstract: Objective The aim of this retrospective study was to review the clinical data and outcomes of patients that suffered ectopic cilium (EC). Animals studied One hundred and twelve dogs from multiple private practices in France, with a clinical diagnosis of EC were included in the study. Results The mean age of affected dogs was 2.3 years. There were 64 females and 48 males. The most represented breeds were the Shi Tzu, the French Bulldog, the English Bulldog and the Chihuahua. Eleven dogs were affected bilaterally. The upper eyelid was implicated in 93.5% of the cases, with the median portion being the most affected. No statistical difference was observed between the right and the left eye. EC were associated with distichiasis in 50% of the cases. Pigmentation of the conjunctiva at the point of exit of the EC was present in 58% of the cases. EC were short in 75% and long in 25% of the cases. Corneal complications were statistically associated with short EC. The corneal lesions associated with EC were keratitis (94%), corneal granuloma (0.8%), corneal fibrosis (2.7%), corneal degeneration (0.8%), superficial corneal ulcer (68.7%), deep corneal ulcer (8%) and perforating corneal ulcer (0.8%). The surgeries which consisted of the removal of the hair follicle was successful in 88.4% of the cases. Conclusion EC is a rare condition which can be treated successfully by the removal of the hair follicles. It must be suspected in cases of corneal lesions unresponsive to medical treatment.
Published: 2021
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2. Towards automated privacy compliance checking of applications in Cloud and Fog environments

Author: Mozhdeh Farhadi, Daniele Miorandi, Guillaume Pierre, U-Hopper srl [Trento], Design and Implementation of Autonomous Distributed Systems (MYRIADS), Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-SYSTÈMES LARGE ÉCHELLE (IRISA-D1), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), This work is part of a project that has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement N° 765452., European Project: 765452,h2020,H2020-MSCA-ITN-2017,FogGuru(2017), Université de Bretagne Sud (UBS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National de Recherche en Informatique et en Automatique (Inria)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-CentraleSupélec-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Bretagne Sud (UBS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1)
Subjects: business.industry, Computer science, Privacy policy, Feature extraction, Cloud computing, Computer security, computer.software_genre, Encryption, Compliance (psychology), Privacy compliance checking, Fog computing, Machine learning, The Internet, Kubernetes, [INFO.INFO-OS]Computer Science [cs]/Operating Systems [cs.OS], Layer (object-oriented design), [INFO.INFO-DC]Computer Science [cs]/Distributed, Parallel, and Cluster Computing [cs.DC], business, Network traffic classification, computer
Abstract: International audience; Internet application users are increasingly concerned about the way applications handle their personal data. However, manually checking whether applications actually respect the claims made in their privacy policy is both error-prone and time-consuming. This paper claims that the privacy compliance of applications hosted in cloud or fog computing platforms can and should be automatically carried by the platform itself. We discuss the feasibility of unintrusive and application-agnostic monitoring in the platform layer to check the privacy compliance of applications. First, the platform may monitor an application's privacy-oriented behavior through signals such as its network traffic characteristics. Second, these signals can be analyzed and compared with the principles found in the application's privacy policy. We present a procedure based on machinelearning techniques to identify the type of data being shared by applications with external third-parties even if the application uses encrypted communications. Our classifiers identify traffic samples of applications with 86% accuracy.
Published: 2021

3. mck8s: An orchestration platform for geo-distributed multi-cluster environments

Author: Johan Tordsson, Mulugeta Ayalew Tamiru, Guillaume Pierre, Erik Elmroth, Elastisys AB, Design and Implementation of Autonomous Distributed Systems (MYRIADS), Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-SYSTÈMES LARGE ÉCHELLE (IRISA-D1), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), This work is part of a project that has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement N° 765452., European Project: 765452,h2020,H2020-MSCA-ITN-2017,FogGuru(2017), Université de Bretagne Sud (UBS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National de Recherche en Informatique et en Automatique (Inria)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-CentraleSupélec-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Bretagne Sud (UBS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1)
Subjects: multi-cluster, business.industry, Computer science, Distributed computing, Resource provisioning, Testbed, Cloud computing, placement, Autoscaling, Resource (project management), autoscaling, Resource allocation, Resource management, Orchestration (computing), scheduling, Kubernetes, [INFO.INFO-OS]Computer Science [cs]/Operating Systems [cs.OS], [INFO.INFO-DC]Computer Science [cs]/Distributed, Parallel, and Cluster Computing [cs.DC], business, Edge computing
Abstract: International audience; Following the adoption of cloud computing, the proliferation of cloud data centers in multiple regions, and the emergence of computing paradigms such as fog computing, there is a need for integrated and efficient management of geodistributed clusters. Geo-distributed deployments suffer from resource fragmentation, as the resources in certain locations are over-allocated while others are under-utilized. Orchestration platforms such as Kubernetes and Kubernetes Federation offer the conceptual models and building blocks that can be used to build integrated solutions that address the resource fragmentation challenge. In this work, we propose mck8s-an orchestration platform for multi-cluster applications on multiple geo-distributed Kubernetes clusters. It offers controllers that automatically place, scale, and burst multi-cluster applications across multiple geo-distributed Kubernetes clusters. mck8s allocates the requested resources to all incoming applications while making efficient use of resources. We designed mck8s to be easy to use by development and operation teams by adopting Kubernetes' design principles and manifest files. We evaluated mck8s in a geo-distributed experimental testbed in Grid'5000. Our results show that mck8s balances the resource allocation across multiple clusters and reduces the fraction of pending pods to 6% as opposed to 65% in the case of Kubernetes Federation for the same workload.
Published: 2021

4. Model-based Stream Processing Auto-scaling in Geo-Distributed Environments

Author: Guillaume Pierre, Erik Elmroth, Hamid Reza Arkian, Johan Tordsson, Design and Implementation of Autonomous Distributed Systems (MYRIADS), Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-SYSTÈMES LARGE ÉCHELLE (IRISA-D1), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Bretagne Sud (UBS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National de Recherche en Informatique et en Automatique (Inria)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-CentraleSupélec-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Bretagne Sud (UBS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Elastisys AB, Umeå University, This work is part of a project that has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement N° 765452., European Project: 765452,h2020,H2020-MSCA-ITN-2017,FogGuru(2017), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique)
Subjects: Computer science, business.industry, auto-scaling, Distributed computing, Process (computing), Control reconfiguration, 020206 networking & telecommunications, Cloud computing, 02 engineering and technology, Data modeling, Stream processing, Resource (project management), 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Enhanced Data Rates for GSM Evolution, [INFO.INFO-OS]Computer Science [cs]/Operating Systems [cs.OS], fog computing, [INFO.INFO-DC]Computer Science [cs]/Distributed, Parallel, and Cluster Computing [cs.DC], business, Throughput (business)
Abstract: International audience; Data stream processing is an attractive paradigm for analyzing IoT data at the edge of the Internet before transmitting processed results to a cloud. However, the relative scarcity of fog computing resources combined with the workloads' nonstationary properties make it impossible to allocate a static set of resources for each application. We propose Gesscale, a resource auto-scaler which guarantees that a stream processing application maintains a sufficient Maximum Sustainable Throughput to process its incoming data with no undue delay, while not using more resources than strictly necessary. Gesscale derives its decisions about when to rescale and which geo-distributed resource(s) to add or remove on a performance model that gives precise predictions about the future maximum sustainable throughput after reconfiguration. We show that this auto-scaler uses 17% less resources, generates 52% fewer reconfigurations, and processes more input data than baseline auto-scalers based on threshold triggers or a simpler performance model. Index Terms-Stream processing, auto-scaling, fog computing.
Published: 2021

5. Stateful Container Migration in Geo-Distributed Environments

Author: Guillaume Pierre, Paulo Souza Junior, Daniele Miorandi, Design and Implementation of Autonomous Distributed Systems (MYRIADS), Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-SYSTÈMES LARGE ÉCHELLE (IRISA-D1), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), U-Hopper srl [Trento], European Project: 765452,h2020,H2020-MSCA-ITN-2017,FogGuru(2017), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Rennes 1 (UR1), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique)
Subjects: File system, Computer science, business.industry, Distributed computing, Volume (computing), 020206 networking & telecommunications, Cloud computing, 02 engineering and technology, computer.software_genre, Stateful firewall, 020204 information systems, Container (abstract data type), 0202 electrical engineering, electronic engineering, information engineering, Data center, [INFO.INFO-OS]Computer Science [cs]/Operating Systems [cs.OS], [INFO.INFO-DC]Computer Science [cs]/Distributed, Parallel, and Cluster Computing [cs.DC], Unavailability, business, computer, Edge computing
Abstract: International audience; Container migration is an essential functionality in large-scale geo-distributed platforms such as fog computing infrastructures. Contrary to migration within a single data center, long-distance migration requires that the container's disk state should be migrated together with the container itself. However, this state may be arbitrarily large, so its transfer may create long periods of unavailability for the container. We propose to exploit the layered structure provided by the OverlayFS file system to transparently snapshot the volumes' contents and transfer them prior to the actual container migration. We implemented this mechanism within Kubernetes. Our evaluations based on a real fog computing test-bed show that our techniques reduce the container's downtime during migration by a factor 4 compared to a baseline with no volume checkpoint.
Published: 2020
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6. An Experimental Evaluation of the Kubernetes Cluster Autoscaler in the Cloud

Author: Guillaume Pierre, Johan Tordsson, Erik Elmroth, Mulugeta Ayalew Tamiru, Elastisys AB, Design and Implementation of Autonomous Distributed Systems (MYRIADS), Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-SYSTÈMES LARGE ÉCHELLE (IRISA-D1), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Bretagne Sud (UBS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National de Recherche en Informatique et en Automatique (Inria)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-CentraleSupélec-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Bretagne Sud (UBS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), European Project: 765452,h2020,H2020-MSCA-ITN-2017,FogGuru(2017), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique)
Subjects: 020203 distributed computing, Computer science, business.industry, Distributed computing, Workload, Cloud computing, 02 engineering and technology, Autoscaling, Elasticity (cloud computing), 0202 electrical engineering, electronic engineering, information engineering, Cluster (physics), 020201 artificial intelligence & image processing, Point (geometry), Kubernetes, [INFO.INFO-OS]Computer Science [cs]/Operating Systems [cs.OS], [INFO.INFO-DC]Computer Science [cs]/Distributed, Parallel, and Cluster Computing [cs.DC], business
Abstract: International audience; Despite the abundant research in cloud autoscaling, autoscaling in Kubernetes, arguably the most popular cloud platform today, is largely unexplored. Kubernetes' Cluster Au-toscaler can be configured to select nodes either from a single node pool (CA) or from multiple node pools (CA-NAP). We evaluate and compare these configurations using two representative applications and workloads on Google Kubernetes Engine (GKE). We report our results using monetary cost and standard autoscaling performance metrics (under-and over-provisioning accuracy, under-and over-provisioning timeshare, instability of elasticity and deviation from the theoretical optimal autoscaler) endorsed by the SPEC Cloud Group. We show that, overall, CA-NAP outperforms CA and that autoscaling performance depends mainly on the composition of the workload. We compare our results with those of the related work and point out further configuration tuning opportunities to improve performance and cost-saving.
Published: 2020
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7. Agricultural Grain Markets in the COVID-19 Crisis, Insights From a GVARModel

Author: Guillaume Pierre and Luciano Gutierrez
Subjects: Coronavirus disease 2019 (COVID-19), Natural resource economics, Agriculture, business.industry, Economics, business
Abstract: The objective of this paper is to combine cross-commodity and spatial price transmission analysis to study the dynamics of the global cereal feed market during the COVID-19 pandemic. After reviewing the nascent literature on the impact of COVID-19 on agricultural markets, we discuss the different impact channels on prices. Then we provide stylized market reactions of three relevant feed markets, wheat, barley and maize to a set of simulated possible future shocks on oil prices, stock-to-use ratios, and export restrictions. These three shocks are useful to assess what could be the consequences of policy responses to the COVID-19 (export restrictions) or disruptions due to the virus (stock-to-use reductions), in a context of lower oil prices. To generate these market reactions, we use a Global Vector Auto Regression (GVAR) model (Dees et al., 2007) where each market is modelled independently, and connected through trade based composite variables. We expand the work of Gutierrez et al. (2015) on the global wheat market by introducing maize and barley. The results of the empirical analysis indicate that the fall in the oil price may have contributed to the stability of the world grain market in early 2020, despite fears of supply chain disruption. We also note that export restrictions could significantly increase global prices, and that such restrictions could affect more than the targeted commodity, through significant cross-commodity price linkages.
Published: 2020
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8. Tail-Latency-Aware Fog Application Replica Placement

Author: Ali J. Fahs and Guillaume Pierre
Subjects: Fog computing, Computer science, End user, business.industry, Replica, 0202 electrical engineering, electronic engineering, information engineering, 020206 networking & telecommunications, 020207 software engineering, 02 engineering and technology, Latency (engineering), Heuristics, business, Computer network
Abstract: Latency-sensitive applications often use fog computing platforms to place replicas of their services as close as possible to their end users. A good placement should guarantee a low tail network latency between end-user devices and their closest replica while keeping the replicas load balanced. We propose a latency-aware scheduler integrated in Kubernetes which uses simple yet highly-effective heuristics to identify suitable replica placements, and to dynamically update these placements upon any evolution of user-generated traffic.
Published: 2020
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9. A systematic approach towards security in Fog computing: assets, vulnerabilities, possible countermeasures

Author: Daniele Miorandi, Guillaume Pierre, Mozhdeh Farhadi, Jean-Louis Lanet, Design and Implementation of Autonomous Distributed Systems (MYRIADS), Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-SYSTÈMES LARGE ÉCHELLE (IRISA-D1), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), U-Hopper srl [Trento], Confidentialité, Intégrité, Disponibilité et Répartition (CIDRE), CentraleSupélec-Inria Rennes – Bretagne Atlantique, Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), European Project: 765452,h2020,H2020-MSCA-ITN-2017,FogGuru(2017), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Rennes 1 (UR1), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique)
Subjects: business.industry, Computer science, Common Criteria, Methodology, Information technology, 020207 software engineering, Cloud computing, Context (language use), 02 engineering and technology, Attack, Space (commercial competition), Computer security, computer.software_genre, Data access, Fog computing, 0202 electrical engineering, electronic engineering, information engineering, Security, [INFO.INFO-OS]Computer Science [cs]/Operating Systems [cs.OS], Layer (object-oriented design), [INFO.INFO-DC]Computer Science [cs]/Distributed, Parallel, and Cluster Computing [cs.DC], business, computer, Software
Abstract: International audience; Fog computing is an emerging paradigm in the IoT space, consisting of a middle computation layer, sitting between IoT devices and Cloud servers. Fog computing provides additional computing, storage and networking resources in close proximity to where data is being generated and/or consumed. As the Fog layer has direct access to data streams generated by IoT devices and responses/commands sent from the Cloud, it is in a critical position in terms of security of the entire IoT system. Currently, there is no specific tool or methodology for analysing the security of Fog computing systems in a comprehensive way. Generic security evaluation procedures applicable to most information technology products are time consuming, costly and badly suited to the Fog context. In this article, we introduce a methodology for evaluating the security of Fog computing systems in a systematic way. We also apply our methodology to a generic Fog computing system, showcasing how it can be purposefully used by security analysts and system designers.
Published: 2020
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10. Docker Image Sharing in Distributed Fog Infrastructures

Author: Arif Ahmed, Guillaume Pierre, Design and Implementation of Autonomous Distributed Systems (MYRIADS), Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-SYSTÈMES LARGE ÉCHELLE (IRISA-D1), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Rennes 1 (UR1), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique)
Subjects: Hardware_MEMORYSTRUCTURES, Docker, Computer science, business.industry, Node (networking), Image sharing, 020206 networking & telecommunications, 02 engineering and technology, Server, Container (abstract data type), 0202 electrical engineering, electronic engineering, information engineering, Fog computing, Cache, [INFO.INFO-OS]Computer Science [cs]/Operating Systems [cs.OS], [INFO.INFO-DC]Computer Science [cs]/Distributed, Parallel, and Cluster Computing [cs.DC], business, ComputingMilieux_MISCELLANEOUS, Container, Computer network, TRACE (psycholinguistics)
Abstract: Fog computing platforms offer virtualized resources located in the vicinity of their end users. Their broad geographical distribution force them to split physical resources in large numbers of relatively weak machines. The limited available disk space per fog node however creates problems for Docker-based systems which locally cache a copy of every container image they execute: first, caches may fill very quickly, whereas standard Docker never automatically evicts any image from its cache. This motivates us to implement automatic cache replacement in Docker. Second, splitting cache space in multiple disjoint partitions negatively impacts the hit rates. This motivates us to propose allowing multiple co-located Docker servers to share their caches. Our trace-based evaluations show that the proposed design achieves significant cache hit improvements, leading to reductions of average container deployment times between 37% and 78% depending on the scenarios.
Published: 2019

11. FogDocker: Start Container Now, Fetch Image Later

Author: Lorenzo Civolani, Guillaume Pierre, Paolo Bellavista, Design and Implementation of Autonomous Distributed Systems (MYRIADS), Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-SYSTÈMES LARGE ÉCHELLE (IRISA-D1), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Rennes 1 (UR1), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Department of Computer Science and Engineering [Bologna] (DISI), Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Civolani, Lorenzo, Pierre, Guillaume, and Bellavista, Paolo
Subjects: Correctness, Docker, business.industry, Computer science, End user, containers, Overhead (engineering), 020207 software engineering, Cloud computing, 02 engineering and technology, computer.software_genre, Software deployment, Server, Container (abstract data type), 0202 electrical engineering, electronic engineering, information engineering, Operating system, Fog computing, 020201 artificial intelligence & image processing, [INFO.INFO-OS]Computer Science [cs]/Operating Systems [cs.OS], [INFO.INFO-DC]Computer Science [cs]/Distributed, Parallel, and Cluster Computing [cs.DC], business, computer, Critical path method
Abstract: International audience; Slow software deployment is an important issue in environments such as fog computing where this operation lies in the critical path of providing online services to the end users. The problem is even worse when the virtualized resources are made of modest machines such as single-board computers. This paper leverages the observation that, although Docker images are often very large, only a small fraction of their content is actually accessed by the containers during startup. We therefore propose to reorganize container images and download only the strictly necessary files before starting a container. The remaining image contents can then be downloaded asynchronously while the container is already running. Our performance evaluations show that FogDocker reduces container deployment times in the order of 3-5x on single-board computers and 2-3x on powerful servers, while incurring low runtime overhead and maintaining correctness even in the case a container accesses a file which was not downloaded yet.
Published: 2019
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12. Proximity-Aware Traffic Routing in Distributed Fog Computing Platforms

Author: Guillaume Pierre, Ali J. Fahs, Design and Implementation of Autonomous Distributed Systems (MYRIADS), Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-SYSTÈMES LARGE ÉCHELLE (IRISA-D1), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Université de Bretagne Sud (UBS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National de Recherche en Informatique et en Automatique (Inria)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-CentraleSupélec-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Bretagne Sud (UBS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1)
Subjects: 020203 distributed computing, Computer science, business.industry, End user, Replica, Proximity-Awareness, Data_MISCELLANEOUS, 020206 networking & telecommunications, Traffic routing, 02 engineering and technology, Fog Computing, Load balancing (computing), Fog computing, 0202 electrical engineering, electronic engineering, information engineering, Load-Balancing, Kubernetes, [INFO.INFO-OS]Computer Science [cs]/Operating Systems [cs.OS], [INFO.INFO-DC]Computer Science [cs]/Distributed, Parallel, and Cluster Computing [cs.DC], business, Computer network
Abstract: International audience; Container orchestration engines such as Kubernetes do not take into account the geographical location of application replicas when deciding which replica should handle which request. This makes them ill-suited to act as a general-purpose fog computing platforms where the proximity between end users and the replica serving them is essential. We present proxy-mity, a proximity-aware traffic routing system for distributed fog computing platforms. It seamlessly integrates in Kubernetes, and provides very simple control mechanisms to allow system administrators to address the necessary trade-off between reducing the user-to-replica latencies and balancing the load equally across replicas. proxy-mity is very lightweight and it can reduce average user-to-replica latencies by as much as 90% while allowing the system administrators to control the level of load imbalance in their system.
Published: 2019
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13. Marsupialization of a cyst of the nictitating membrane in three dogs

Author: Julien Charron, Frédéric Goulle, Isabelle Raymond-Letron, Charlotte Barbé, and Guillaume-Pierre Mias
Subjects: medicine.medical_specialty, General Veterinary, 040301 veterinary sciences, business.industry, medicine.medical_treatment, Postoperative complication, 04 agricultural and veterinary sciences, Marsupialization, medicine.disease, Surgery, 0403 veterinary science, Lesion, 03 medical and health sciences, 0302 clinical medicine, Palpebral fissure, 030221 ophthalmology & optometry, medicine, Cyst, Nictitating membrane, medicine.symptom, business, Complication, Ophthalmologic Surgical Procedure
Abstract: Background Development of cysts has been reported as a potential complication after surgical repositioning of nictitating membrane gland protrusion using the conjunctival pocket technique. To the authors' knowledge, no treatment for these cysts has ever been published. Objectives This short case series describes a surgical technique of marsupialization as a treatment option for these cysts and proposes a pathogenesis for cyst formation. Cases description Three dogs were each referred for a unilateral subconjunctival mass-like lesion involving the bulbar side of the nictitating membrane. Complete ophthalmologic examination revealed a pink, translucent, soft, and nonpainful mass protruding from the bulbar surface of the nictitating membrane in all cases. Treatment consisted in marsupialization of the cyst on the palpebral surface of the nictitating membrane and was curative with no short-term postoperative complication and favorable long-term outcome for the three dogs. Histopathological findings were consistent with a lacrimal cyst. Conclusion Marsupialization appears to be a safe, simple, and effective treatment for nictitating membrane cyst secondary to surgical correction of gland prolapse using conjunctival pocket technique in dogs. Further studies on a larger number of cases are necessary to determine whether marsupialization is the technique of choice and to further investigate the pathophysiology of cyst formation after conjunctival pocket repositioning of prolapsed glands.
Published: 2016
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14. Fabrication methods of sustainable hydrogels

Author: Guillaume Pierre, Mitsuru Akashi, Michiya Matsusaki, Philippe Michaud, Cédric Delattre, Fiona Louis, Institut Pascal (IP), SIGMA Clermont (SIGMA Clermont)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Physicochimie des Processus de Combustion et de l’Atmosphère - UMR 8522 (PC2A), Université de Lille-Centre National de la Recherche Scientifique (CNRS), Inamuddin, Thomas S., Kumar Mishra R., Asiri A., and SIGMA Clermont (SIGMA Clermont)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])
Subjects: Engineering, business.industry, Nanotechnology, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Coating system, Fabrication methods, Self-healing hydrogels, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, 0210 nano-technology, business, ComputingMilieux_MISCELLANEOUS
Abstract: The interest received on hydrogels probably reflects one of the greatest challenges for the two last decades. Able to hold and release solvents and builds, these three-dimensional polymeric structures work as a network able to reversibly change in response to small physico-chemical modifications in their surroundings. Considering the fantastic amount of available techniques described in the literature, a brief overview of the fabrication methodology is synthesized from physical/chemical cross-linking or polymerization grafting to radiation cross-linking. Thus, this review explores the fabrication and recent applications of hydrogels in various fields including imaging, optics, diagnostics, drug delivery systems or tissue engineering. Extensive use of hydrogels raises some questions about life cycle assessment and how fabricating and/or using sustainable and innovative versions of the intelligent hydrogels of tomorrow.
Published: 2019

15. An experiment-driven energy consumption model for virtual machine management systems

Author: Lavinia Samoila, Mar Callau-Zori, Guillaume Pierre, Anne-Cécile Orgerie, Design and Implementation of Autonomous Distributed Systems (MYRIADS), Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-SYSTÈMES LARGE ÉCHELLE (IRISA-D1), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Bretagne Sud (UBS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National de Recherche en Informatique et en Automatique (Inria)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-CentraleSupélec-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Bretagne Sud (UBS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Centre National de la Recherche Scientifique (CNRS), Grid'5000, Design and Implementation of Autonomous Distributed Systems ( MYRIADS ), Institut National de Recherche en Informatique et en Automatique ( Inria ) -Institut National de Recherche en Informatique et en Automatique ( Inria ) -SYSTÈMES LARGE ÉCHELLE ( IRISA_D1 ), Institut de Recherche en Informatique et Systèmes Aléatoires ( IRISA ), Université de Rennes 1 ( UR1 ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Institut National des Sciences Appliquées - Rennes ( INSA Rennes ) -Université de Bretagne Sud ( UBS ) -École normale supérieure - Rennes ( ENS Rennes ) -Institut National de Recherche en Informatique et en Automatique ( Inria ) -CentraleSupélec-Centre National de la Recherche Scientifique ( CNRS ) -IMT Atlantique Bretagne-Pays de la Loire ( IMT Atlantique ) -Université de Rennes 1 ( UR1 ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Institut National des Sciences Appliquées - Rennes ( INSA Rennes ) -Université de Bretagne Sud ( UBS ) -École normale supérieure - Rennes ( ENS Rennes ) -Institut National de Recherche en Informatique et en Automatique ( Inria ) -CentraleSupélec-Centre National de la Recherche Scientifique ( CNRS ) -IMT Atlantique Bretagne-Pays de la Loire ( IMT Atlantique ) -Institut de Recherche en Informatique et Systèmes Aléatoires ( IRISA ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Institut National des Sciences Appliquées - Rennes ( INSA Rennes ) -Université de Bretagne Sud ( UBS ) -École normale supérieure - Rennes ( ENS Rennes ) -CentraleSupélec-Centre National de la Recherche Scientifique ( CNRS ) -IMT Atlantique Bretagne-Pays de la Loire ( IMT Atlantique ), Centre National de la Recherche Scientifique ( CNRS ), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique)
Subjects: General Computer Science, Cloud management, Computer science, Distributed computing, [ INFO.INFO-NI ] Computer Science [cs]/Networking and Internet Architecture [cs.NI], Cloud computing, 02 engineering and technology, computer.software_genre, [INFO.INFO-NI]Computer Science [cs]/Networking and Internet Architecture [cs.NI], Green computing, [ INFO.INFO-DC ] Computer Science [cs]/Distributed, Parallel, and Cluster Computing [cs.DC], 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering, Energy model, Virtual Machine migration, business.industry, 020206 networking & telecommunications, Energy consumption, Virtual Machine Management, Virtual machine, Management system, Benchmark (computing), 020201 artificial intelligence & image processing, [INFO.INFO-DC]Computer Science [cs]/Distributed, Parallel, and Cluster Computing [cs.DC], business, computer, Host (network)
Abstract: International audience; As energy consumption is becoming critical in Cloud data centers, Cloud providers are adopting energy-efficient virtual machines management systems. These systems essentially rely on " what-if " analysis to determine what the consequence of their actions would be and to choose the best one according to a number of metrics. However, modeling energy consumption of simple operations such as starting a new VM or live-migrating is complicated by the fact that multiple phenomena occur. It is therefore important to identify which factors influence energy consumption before proposing any new model. We claim in this paper that one critical parameter is the host configuration, characterized by the number of VMs it is currently executing. Based on this observation, we present an energy model that provides energy estimation associated with VM management operations, such as VMs placement, VM start up and VM migration. The average relative estimation error is lower than 10% using the transactional web benchmark TPC-W, making it a good candidate for driving the actions of future energy-aware cloud management systems.
Published: 2018
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16. Development of large aperture, high-frequency piezo-electric transducers for photoacoustic imaging

Author: Sophie Crozat, Harold Barquero, and Guillaume Pierre
Subjects: Electromechanical coupling coefficient, Materials science, business.industry, Acoustics, Attenuation, Bandwidth (signal processing), 02 engineering and technology, Dielectric, Acoustic wave, 021001 nanoscience & nanotechnology, 030218 nuclear medicine & medical imaging, 03 medical and health sciences, 0302 clinical medicine, Optics, Insertion loss, Center frequency, 0210 nano-technology, business, Electrical impedance
Abstract: In the recent years, SONAXIS has developed lens-focused ultrasound transducers (LFUTs) with central frequencies greater than 10MHz, and −6dB relative bandwidth larger than 120%. For instance the use of one of these transducers — 78MHz central frequency, 128% relative bandwidth, f/D≈1 — has been reported for biomedical imaging applications [Soliman et al., 2015]. Drawbacks of LFUTs include the attenuation of high-frequency (HF) acoustic waves by the lens material as well as reflexions in the lens. Lensless, self-focused ultrasound transducers (SFUTs) have been proposed as an alternative to LFUTs and have been reported to provide reduced insertion loss compared to the latter [Cannata et al., 2000]. Adequate design of piezocomposite materials (PCMs) make them suitable candidates for biomedical applications, since they can meet requirements in terms of electromechanical coupling coefficient, acoustical impedance, dielectric constant as well as dielectric and mechanical losses [Smith and Auld, 1991]. This study aims at the development and evaluation of SFUTs based on 1–3 PCMs for biomedical applications, as an alternative to LFUTs, with broad bandwidth and high central frequency.
Published: 2017
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17. Valorization of carob waste: Definition of a second-generation bioethanol production process

Author: Agnès Pons, Guillaume Pierre, Christophe Vial, Samir Taha, Hajar Bahry, Cédric Delattre, Rawa Abdallah, Nidal Fayad, Institut Pascal (IP), SIGMA Clermont (SIGMA Clermont)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020]), Université Libanaise, Centre AZM pour la Recherche en Biotechnologie et ses Applications, Centre AZM pour la recherche en Biotechnologie et ses applications, Ecole Doctorale des Sciences et de la Technologie (EDST), Lebanese University [Beirut] (LU)-Lebanese University [Beirut] (LU), Institut Pascal, and SIGMA Clermont (SIGMA Clermont)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)
Subjects: Second generation bioethanol, Environmental Engineering, Municipal solid waste, Food industry, 020209 energy, Bioengineering, 02 engineering and technology, Saccharomyces cerevisiae, 010501 environmental sciences, 01 natural sciences, chemistry.chemical_compound, Carob by-product, Solid-state fermentation, 0202 electrical engineering, electronic engineering, information engineering, Ethanol fuel, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, Sugar, Waste Management and Disposal, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Ethanol, Waste management, Renewable Energy, Sustainability and the Environment, business.industry, Fabaceae, General Medicine, Pulp and paper industry, Submerged fermentation, Sugar extraction, chemistry, Biofuel, 8. Economic growth, Fermentation, Environmental science, business
Abstract: The aim of this work was to develop a strategy for second-generation ethanol production from carob solid waste issued from Lebanese food industry. The pros and cons of submerged (SF) and solid-state fermentations (SSF) using S. cerevisiae on ethanol yield and productivity were compared, including the respective roles of upstream and downstream processes, such as the size reduction, or sugar and ethanol recovery processes. The design of experiments methodology was applied. Experimental results demonstrated that SSF applied to cut carob waste from carob syrup preparation was simpler to operate and more cost-effective, maintained yield and productivity (0.458g ethanol/g consumed sugar and 4.3g/(kg waste)/h) in comparison to SF (0.450g ethanol/g consumed sugar and 5.7g/(kg waste)/h), and was able to achieve ethanol production up to 155g/(kg waste) at low water demand, while SF reached only 78g/(kg waste) due to the limitations of the sugar extraction pretreatment.
Published: 2017
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18. The HARNESS Platform: A Hardware-and Network-Enhanced Software System for Cloud Computing

Author: Anca Iordache, John McGlone, Guillaume Pierre, Mark Stillwell, Katerina Argyraki, Peter Sanders, George Ioannidis, Christoph Kleineweber, Jose G. F. Coutinho, Alexander L. Wolf, Thorsten Schütt, Carmelo Ragusa, Alexandros Koliousis, Teng Yu, Imperial College London, Ecole Polytechnique Fédérale de Lausanne (EPFL), Design and Implementation of Autonomous Distributed Systems (MYRIADS), Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-SYSTÈMES LARGE ÉCHELLE (IRISA-D1), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Université de Rennes (UR), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Konrad-Zuse-Zentrum für Informationstechnik Berlin (ZIB), Zuse Institute Berlin (ZIB), SAP, Maxeler Technologies, University of California [Santa Cruz] (UC Santa Cruz), University of California (UC), Ivan Mistrik, Rami Bahsoon, Nour Ali, Maritta Heisel, Bruce Maxim, European Project: 318521,EC:FP7:ICT,FP7-ICT-2011-8,HARNESS(2012), Université de Bretagne Sud (UBS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National de Recherche en Informatique et en Automatique (Inria)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-CentraleSupélec-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Bretagne Sud (UBS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES), CentraleSupélec-Télécom Bretagne-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National de Recherche en Informatique et en Automatique (Inria)-École normale supérieure - Rennes (ENS Rennes)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), University of California [Santa Cruz] (UCSC), and University of California
Subjects: [INFO.INFO-AR]Computer Science [cs]/Hardware Architecture [cs.AR], Data processing, ACM: C.: Computer Systems Organization/C.2: COMPUTER-COMMUNICATION NETWORKS/C.2.4: Distributed Systems, business.industry, Computer science, Distributed computing, 05 social sciences, Testbed, 050301 education, Online machine learning, 020206 networking & telecommunications, Cloud computing, 02 engineering and technology, Domain (software engineering), [INFO.INFO-PF]Computer Science [cs]/Performance [cs.PF], 0202 electrical engineering, electronic engineering, information engineering, Software system, [INFO.INFO-OS]Computer Science [cs]/Operating Systems [cs.OS], [INFO.INFO-DC]Computer Science [cs]/Distributed, Parallel, and Cluster Computing [cs.DC], Resource management (computing), business, Field-programmable gate array, 0503 education
Abstract: International audience; HARNESS is a next generation cloud-computing platform that offers commodity and specialized resources in support of large-scale data processing applications. We focus primarily on application domains that are currently not well supported by today's cloud providers, including the areas of scientific computing, business-analytics, and online machine learning. These applications often require acceleration of critical operations using devices such as FPGAs, GPGPUs, network middleboxes, and SSDs. We explain the architectural principles that underlie the HARNESS platform, including the separation of agnostic and cognizant resource management that allows the platform to be resilient to heterogeneity while leveraging its use. We describe a prototype implementation of the platform, which was evaluated using two testbeds: (1) a heterogeneous compute and storage cluster that includes FPGAs and SSDs and (2) Grid'5000, a large-scale distributed testbed that spans France. We evaluate the HARNESS cloud-computing platform with two applications: Reverse-Time Migration, a scientific computing application from the geosciences domain, and AdPredictor, a machine learning algorithm used in the Bing search engine.
Published: 2017

19. MEC-ConPaaS: An Experimental Single-Board Based Mobile Edge Cloud

Author: Alexandre van Kempen, Teodor Crivat, Guillaume Pierre, Debaditya Roy, Benjamin Trubert, Design and Implementation of Autonomous Distributed Systems (MYRIADS), Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-SYSTÈMES LARGE ÉCHELLE (IRISA-D1), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Bretagne Sud (UBS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National de Recherche en Informatique et en Automatique (Inria)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-CentraleSupélec-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Bretagne Sud (UBS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Cloudtech Star Software, Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Rennes 1 (UR1), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique)
Subjects: 020203 distributed computing, Computer science, business.industry, Distributed computing, Mobile computing, 020206 networking & telecommunications, Cloud computing, 02 engineering and technology, Utility computing, Cloud testing, 0202 electrical engineering, electronic engineering, information engineering, Mobile search, [INFO.INFO-OS]Computer Science [cs]/Operating Systems [cs.OS], Enhanced Data Rates for GSM Evolution, Mobile telephony, business, Edge computing
Abstract: International audience; Cloud infrastructures are extremely flexible and powerful, but their data centers are located very far from the end users. To address the limitations of these systems, many researchers are designing mobile edge clouds which complement traditional clouds with additional resources located in immediate proximity of the end users. However, currently there exists no open-source mobile edge cloud implementation which can easily be deployed over a campus or a city center to support real-world experimentations. We therefore present the design and implementation of MEC-ConPaaS, a mobile-edge cloud platform, which aims to support future research on edge cloud applications and middlewares. The system exploits single-board computers such as Raspberry Pis which are an order of magnitude cheaper than any server machine and much easier to setup in a distributed setting. We demonstrate that these devices are powerful enough to support real cloud applications, and to support further research on these topics.
Published: 2017
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20. High Performance in the Cloud with FPGA Groups

Author: Jose G. F. Coutinho, Mark Stillwell, Guillaume Pierre, Anca Iordache, Peter Sanders, Design and Implementation of Autonomous Distributed Systems (MYRIADS), Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-SYSTÈMES LARGE ÉCHELLE (IRISA-D1), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Maxeler Technologies, Imperial College London, European Project: 318521,EC:FP7:ICT,FP7-ICT-2011-8,HARNESS(2012), CentraleSupélec-Télécom Bretagne-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National de Recherche en Informatique et en Automatique (Inria)-École normale supérieure - Rennes (ENS Rennes)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Télécom Bretagne-Université de Rennes 1 (UR1), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-École normale supérieure - Rennes (ENS Rennes)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)
Subjects: Multitenancy, Architectural model, business.industry, Computer science, Cloud computing, 02 engineering and technology, Multi-tenancy, Virtualization, computer.software_genre, Reconfigurable computing, Autoscaling, 020202 computer hardware & architecture, 020204 information systems, Embedded system, 0202 electrical engineering, electronic engineering, information engineering, Resource allocation, Resource management, [INFO.INFO-OS]Computer Science [cs]/Operating Systems [cs.OS], [INFO.INFO-DC]Computer Science [cs]/Distributed, Parallel, and Cluster Computing [cs.DC], business, Field-programmable gate array, computer, FPGA, Accelerators
Abstract: International audience; Field-programmable gate arrays (FPGAs) can offer invaluable computational performance for many compute-intensive algorithms. However, to justify their purchase and administration costs it is necessary to maximize resource utilization over their expected lifetime. Making FPGAs available in a cloud environment would make them attractive to new types of users and applications and help democratize this increasingly popular technology. However, there currently exists no satisfactory technique for offering FPGAs as cloud resources and sharing them between multiple tenants. We propose FPGA groups, which are seen by their clients as a single virtual FPGA, and which aggregate the computational power of multiple physical FPGAs. FPGA groups are elastic, and they may be shared among multiple tenants. We present an autoscaling algorithm to maximize FPGA groups' resource utilization and reduce user-perceived computation latencies. FPGA groups incur a low overhead in the order of 0.09ms per submitted task. When faced with a challenging workload, the autoscaling algorithm increases resource utilization from 52% to 61% compared to a static resource allocation, while reducing task execution latencies by 61%.
Published: 2016

21. The XtreemOS Resource Selection Service

Author: Corina Stratan, Paolo Costa, Jan Sacha, Jeff Napper, and Guillaume Pierre
Subjects: Service (systems architecture), Database, business.industry, Computer science, Distributed computing, Node (networking), RSS, computer.file_format, computer.software_genre, Set (abstract data type), Software, Resource (project management), Utility computing, Control and Systems Engineering, Scalability, Computer Science (miscellaneous), business, computer
Abstract: Many large-scale utility computing infrastructures comprise heterogeneous hardware and software resources. This raises the need for scalable resource selection services that identify resources that match application requirements. Such a service must provide an efficient lookup in spite of changing resource attributes such as disk size, changing application requirements such as installed software libraries, and changing system composition as resources join or leave. We present a fully decentralized, self-managing Resource Selection Service (RSS) algorithm by which resources autonomously select themselves when their attributes match a query. An application specifies what it expects from a resource by means of a conjunction of (attribute,value-range) pairs, which are matched against the attribute values of resources. The set of search attributes can also be updated online to reflect new requirements. We show that our solution scales in the number of resources and in the number of attributes, while being relatively insensitive to churn and other membership changes like node failures. Our RSS continuously self-adapts its routing structure in response to variations in the distribution of node attributes and queries. We show that this autonomous optimization maintains performance and availability in a long-lived service even when the set of application requirements used to select resources changes.
Published: 2012
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22. ConPaaS: a Platform for Hosting Elastic Cloud Applications

Author: Guillaume Pierre, Corina Stratan, Computer Systems, Network Institute, and Distributed Computer Systems
Subjects: 020203 distributed computing, Open platform, Cloud computing security, Computer Networks and Communications, business.industry, Computer science, Software as a service, Distributed computing, 020206 networking & telecommunications, Cloud computing, Provisioning, 02 engineering and technology, Cloud testing, Scalability, 0202 electrical engineering, electronic engineering, information engineering, Resource management, business
Abstract: ConPaaS is an open source platform-as-a-service environment that aims at simplifying the deployment of cloud applications. In ConPaaS, an application is defined as a composition of one or more services. Each service is self-managed and elastic: it can deploy itself on the cloud, monitor its own performance, and increase or decrease its processing capacity through dynamic resource provisioning. © 2012 IEEE.
Published: 2012
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23. CloudTPS: Scalable Transactions for Web Applications in the Cloud

Author: Guillaume Pierre, Chi-Hung Chi, and Zhou Wei
Subjects: Information Systems and Management, Database, Distributed database, Computer Networks and Communications, Computer science, business.industry, Cloud computing, NoSQL, computer.software_genre, Computer Science Applications, Hardware and Architecture, Cloud testing, Server, Scalability, Distributed transaction, Web application, business, computer
Abstract: NoSQL cloud data stores provide scalability and high availability properties for web applications, but at the same time they sacrifice data consistency. However, many applications cannot afford any data inconsistency. CloudTPS is a scalable transaction manager which guarantees full ACID properties for multi-item transactions issued by web applications, even in the presence of server failures and network partitions. We implement this approach on top of the two main families of scalable data layers: Bigtable and SimpleDB. Performance evaluation on top of HBase (an open-source version of Bigtable) in our local cluster and Amazon SimpleDB in the Amazon cloud shows that our system scales linearly at least up to 40 nodes in our local cluster and 80 nodes in the Amazon cloud.
Published: 2012
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24. Enabling service adaptability with versatile anycast

Author: Mariana Simons-Nikolova, Maarten van Steen, Michal Szymaniak, Guillaume Pierre, Computer Systems, and Distributed Computer Systems
Subjects: Service (systems architecture), Computer Networks and Communications, business.industry, Computer science, Distributed computing, ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS, Computer Science Applications, Theoretical Computer Science, Logical address, Computational Theory and Mathematics, Handover, Mobile IP, Anycast, Overhead (computing), SDG 7 - Affordable and Clean Energy, business, Software, Computer network
Abstract: We present versatile anycast, which allows a service running on a varying collection of nodes scattered over a wide-area network to present itself to the clients as one running on a single node. Providing a single logical address enables the client-side software to preserve the traditional service access model based on single access points. At the same time, the dynamic composition of anycast groups implemented by versatile anycast enables the server-side service infrastructure to evolve and adapt to changing network conditions. We implement versatile anycast using Mobile IPv6, which decouples the logical addresses of mobile nodes from their physical location. We exploit that decoupling to implement logical service addresses that are not bound to any physical nodes, and employ standard MIPv6 mechanisms to dynamically map each such address onto individual service nodes. Our solution enables a service to transparently hand off clients among the service nodes at the network level while preserving optimal routing between the clients and the service nodes. We demonstrate that the overhead of versatile anycasting is very low. In particular, the client-perceived handoff time is shown to be a linear function of the latencies among the client and the service nodes participating in the handoff. Copyright © 2007 John Wiley & Sons, Ltd.
Published: 2007
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25. HARNESS

Author: Guillaume Pierre
Subjects: Software, business.industry, Computer science, Distributed computing, Resource allocation, Context (language use), Hypervisor, Cloud computing, business, Field-programmable gate array, Computer hardware
Abstract: Today's cloud platforms are missing out on the revolution in new hardware and network technologies for realising vastly richer computation, communication, and storage solutions. Technologies such as FPGAs and GPGPUs, programmable network routers, and solid-state disks bring new degrees of freedom to resource allocation and optimisation. However, their heterogeneity and complexity makes their integration with standard Platform-as-a-Service (PaaS) frameworks a fundamental challenge. HARNESS investigates how cloud providers can profitably manage specialised hardware and network technologies much as they do today's commodity resources, and software engineers can seamlessly integrate them into the design of their cloud-hosted applications. I will present the challenges that arise when integrating devices with no OS nor hypervisor in a cloud environment, and techniques to model and control application performance in this context.
Published: 2015
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26. Heterogeneous Resource Selection for Arbitrary HPC Applications in the Cloud

Author: Anca Iordache, Guillaume Pierre, Eliya Buyukkaya, Design and Implementation of Autonomous Distributed Systems (MYRIADS), Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-SYSTÈMES LARGE ÉCHELLE (IRISA-D1), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), HARNESS FP7 project, Alysson Bessani, Sara Bouchenak, TC 6, WG 6.1, Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)
Subjects: 020203 distributed computing, Cloud resources, business.industry, Computer science, Distributed computing, Cloud computing, 02 engineering and technology, Execution Time, Pareto Frontier, Public Cloud, Cloud Infrastructure, Cloud User, Execution time, Variety (cybernetics), Constraint (information theory), Resource (project management), 020204 information systems, 0202 electrical engineering, electronic engineering, information engineering, Selection (linguistics), [INFO.INFO-OS]Computer Science [cs]/Operating Systems [cs.OS], [INFO.INFO-DC]Computer Science [cs]/Distributed, Parallel, and Cluster Computing [cs.DC], business, Performance model
Abstract: International audience; Cloud infrastructures offer a wide variety of resources to choose from. However, most cloud users ignore the potential benefits of dynamically choosing cloud resources among a wide variety of VM instance types with different con-figuration/cost tradeoffs. We propose to automate the choice of resources that should be assigned to arbitrary non-interactive applications. During the first executions of the application, the system tries various resource configurations and builds a custom performance model for this application. Thereafter, cloud users can specify their execution time or financial cost constraints, and let the system automatically select the resources which best satisfy this constraint.
Published: 2015
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27. Kangaroo: A Tenant-Centric Software-Defined Cloud Infrastructure

Author: Guillaume Pierre, Thilo Kielmann, Kaveh Razavi, Ana Ion, Kyuho Jeong, Genc Tato, Renato Figueiredo, Department of Computer Science [Amsterdam], Vrije Universiteit Amsterdam [Amsterdam] (VU), Université de Rennes (UR), Design and Implementation of Autonomous Distributed Systems (MYRIADS), Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-SYSTÈMES LARGE ÉCHELLE (IRISA-D1), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), University of Florida [Gainesville] (UF), This work is partially funded by the FP7 Programme of the European Commission in the context of the Contrail project under Grant Agreement FP7-ICT-257438, the HARNESS project under Grant Agreement FP7-ICT-318521, the Dutch public-private research community COMMIT/, and the National Science Foundation under Grants No. 1339737 and 1234983., European Project: 257438,EC:FP7:ICT,FP7-ICT-2009-5,CONTRAIL(2010), European Project: 318521,EC:FP7:ICT,FP7-ICT-2011-8,HARNESS(2012), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Computer Systems, Network Institute, High Performance Distributed Computing, and Distributed Computer Systems
Subjects: Software_OPERATINGSYSTEMS, Computer science, Interface (Java), Cloud computing, 02 engineering and technology, Overlay, computer.software_genre, [INFO.INFO-NI]Computer Science [cs]/Networking and Internet Architecture [cs.NI], Software, 0202 electrical engineering, electronic engineering, information engineering, Innovation, Downtime, business.industry, Software-defined data center, 020206 networking & telecommunications, 020207 software engineering, Virtual machine, Software deployment, Operating system, and Infrastructure, SDG 9 - Industry, Innovation, and Infrastructure, [INFO.INFO-OS]Computer Science [cs]/Operating Systems [cs.OS], [INFO.INFO-DC]Computer Science [cs]/Distributed, Parallel, and Cluster Computing [cs.DC], business, computer, SDG 9 - Industry
Abstract: International audience; Applications on cloud infrastructures acquire virtual machines (VMs) from providers when necessary. The current interface for acquiring VMs from most providers, however, is too limiting for the tenants, in terms of granularity in which VMs can be acquired (e.g., small, medium, large, etc.), while giving very limited control over their placement. The former leads to VM underutilization, and the latter has performance implications, both translating into higher costs for the tenants. In this work, we leverage nested virtualization and a networking overlay to tackle these problems. We present Kangaroo, an OpenStack-based virtual infrastructure provider, and IPOPsm, a virtual networking switch for communication between nested VMs over different infrastructure VMs. In addition, we design and implement Skippy, the realization of our proposed virtual infrastructure API for programming Kangaroo. Our benchmarks show that through careful mapping of nested VMs to infrastructure VMs, Kangaroo achieves up to an order of magnitude better performance, with only half the cost on Amazon EC2. Further, Kangaroo's unified OpenStack API allows us to migrate an entire application between Amazon EC2 and our local OpenNebula deployment within a few minutes, without any downtime or modification to the application code.
Published: 2015

28. Latency-Driven Replica Placement

Author: Michal Szymaniak, Maarten van Steen, Guillaume Pierre, Computer Systems, and Distributed Computer Systems
Subjects: Computational complexity theory, Computer science, business.industry, Replica, Client server systems, Data_MISCELLANEOUS, Latency (engineering), Greedy algorithm, business, Geometric modeling, Topology, General Economics, Econometrics and Finance, Computer network
Abstract: This paper presents HotZone, an algorithm to place replicas in a wide-area network such that the client-to-replica latency is minimized. Similar to the previously proposed HotSpot algorithm, HotZone places replicas on nodes that along with their neighboring nodes generate the highest load. In contrast to HotSpot, however, HotZone provides nearly-optimal results by considering overlapping neighborhoods. HotZone relies on a geometric model of Internet latencies, which effectively reduces the cost of placing K replicas among N potential replica locations from O(N/sup 2/) to O(N /spl middot/ max(logN, K)).
Published: 2006
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29. Robust Performance Control for Web Applications in the Cloud

Author: Guillaume Pierre, Hector Fernandez, Corina Stratan, Department of Computer Science [Amsterdam], Vrije Universiteit Amsterdam [Amsterdam] (VU), Department of Computer Science, Vrije Universiteit Amsterdam [Amsterdam] (VU)-Vrije Universiteit Amsterdam [Amsterdam] (VU), Design and Implementation of Autonomous Distributed Systems (MYRIADS), Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-SYSTÈMES LARGE ÉCHELLE (IRISA-D1), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), European Project: 318521,EC:FP7:ICT,FP7-ICT-2011-8,HARNESS(2012), CentraleSupélec-Télécom Bretagne-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National de Recherche en Informatique et en Automatique (Inria)-École normale supérieure - Rennes (ENS Rennes)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Télécom Bretagne-Université de Rennes 1 (UR1), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-École normale supérieure - Rennes (ENS Rennes)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)
Subjects: Computer science, business.industry, Workload, Cloud computing, Provisioning, Computer security, computer.software_genre, Performance control, Elasticity (cloud computing), High availability, Cloud testing, Web application, [INFO.INFO-OS]Computer Science [cs]/Operating Systems [cs.OS], business, computer
Abstract: Best paper award; International audience; With the success of Cloud computing, more and more websites have been moved to cloud platforms. The elasticity and high availability of cloud solutions are attractive features for hosting web applications. In particular, the elasticity is supported through trigger-based provisioning systems that dynamically add/release resources when certain conditions are met. However, when dealing with websites, this operation becomes more problematic, as the workload demand fluctuates following an irregular pattern. An excessive reactiveness turns these systems into imprecise and wasteful in terms of SLA fulfillment and resource consumption. In this paper, we propose three different provisioning techniques that expose the limitations of traditional systems, and overcomes their drawbacks without overly increasing complexity. Our experiments conducted on both public and private infrastructures show significant reductions in SLA violations while offering performance stability.
Published: 2014

30. Autoscaling Web Applications in Heterogeneous Cloud Infrastructures

Author: Guillaume Pierre, Thilo Kielmann, Hector Fernandez, Computer Systems, Network Institute, High Performance Distributed Computing, Distributed Computer Systems, Department of Computer Science [Amsterdam], Vrije Universiteit Amsterdam [Amsterdam] (VU), Design and Implementation of Autonomous Distributed Systems (MYRIADS), Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-SYSTÈMES LARGE ÉCHELLE (IRISA-D1), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), European Project: 318521,EC:FP7:ICT,FP7-ICT-2011-8,HARNESS(2012), CentraleSupélec-Télécom Bretagne-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National de Recherche en Informatique et en Automatique (Inria)-École normale supérieure - Rennes (ENS Rennes)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Télécom Bretagne-Université de Rennes 1 (UR1), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-École normale supérieure - Rennes (ENS Rennes)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)
Subjects: Computer science, business.industry, Quality of service, 020206 networking & telecommunications, Workload, Cloud computing, Provisioning, 02 engineering and technology, Autoscaling, Resource (project management), Server, 0202 electrical engineering, electronic engineering, information engineering, Web application, 020201 artificial intelligence & image processing, [INFO.INFO-OS]Computer Science [cs]/Operating Systems [cs.OS], business, Computer network
Abstract: International audience; Improving resource provisioning of heterogeneous cloud infrastructures is an important research challenge. The wide diversity of cloud-based applications and customers with different QoS requirements have recently exhibited the weaknesses of current provisioning systems. Today's cloud infrastructures provide provisioning systems that dynamically adapt the computational power of applications by adding or releasing resources. Unfortunately, these scaling systems are fairly limited: (i) They restrict themselves to a single type of resource; (ii) they are unable to fulfill QoS requirements in face of spiky workload; and (iii) they offer the same QoS level to all their customers, independent of customer preferences such as different levels of service availability and performance. In this paper, we present an autoscaling system that overcomes these limitations by exploiting heterogeneous types of resources, and by defining multiple levels of QoS requirements. The proposed system selects a resource scaling plan according to both workload and customer requirements. Our experiments conducted on both public and private infrastructures show significant reductions in QoS-level violations when faced with highly variable workloads.
Published: 2014
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31. Ultrasound transmission spectroscopy: in-line sizing of nanoparticles

Author: A.W.F. Volker, Sophie Crozat, F. Bouvet, P.L.M.J. van Neer, and Guillaume Pierre
Subjects: Nanoparticle sizing, TS - Technical Sciences, Materials science, Industrial Innovation, PID - Process & Instrument Development, Opacity, Ultrasound spectroscopy, Scattering, business.industry, Fluid Mechanics Chemistry & Energetics, Ultrasound, Analytical chemistry, Nanoparticle, High Tech Systems & Materials, symbols.namesake, symbols, Transmission spectroscopy, Particle, Ultrasonic sensor, Particle size, Rayleigh scattering, Electronics, business
Abstract: Nanoparticles are increasingly used in a number of applications, e.g. coatings or paints. To optimize nanoparticle production in-line quantitative measurements of their size distribution and concentration are needed. Ultrasound-based methods are especially suited for in-line particle sizing. These methods can be used for opaque dispersions and at high concentrations. However, using ultrasound to measure nanoparticles is challenging: despite the use of high frequencies the scattering is close to the Rayleigh regime (ka ≪ 1) and the information contained in the measurements is limited. In this work the performance of an ultrasonic particle sizing method is evaluated using SiO 2 nanoparticles. The measurement method is based on ultrasound transmission spectroscopy. The presence of nanoparticles affects the propagation of ultrasound in the medium, which is measured over a frequency band of 50 – 250 MHz. The wave propagation effects are then interpreted using the inversion of a physics model. The investigated dispersions consisted of SiO 2 nanoparticles (1.4 and 2.0 vol%) dispersed in water. Four batches, provided by Nano-H S.A.S., had monomodal size distributions with mean sizes 150, 300, 420 and 440 nm. Two bimodal size distributions were investigated: 1) a mix of 50% 302 nm and 50% 422 nm particles, and 2) a mix of 50% 150 nm and 50% 422 nm particles. As a reference the size distributions were measured using an optics based Malvern Zetasizer. The mean particle sizes and concentrations were similar to the reference, with differences between 4.5 and 19% and between 3 and 15%, respectively. The shape of the particle size distributions obtained by the ultrasonic instrument were similar to that of the reference. Also, the ultrasound instrument was able to produce correct results for both mono- and bimodal size distributions. The temperature of the mixture did not have a significant influence on the results.
Published: 2014

32. Failure Analysis and Modeling in Large Multi-site Infrastructures

Author: Guillaume Pierre, Tran Ngoc Minh, Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), CentraleSupélec-Télécom Bretagne-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National de Recherche en Informatique et en Automatique (Inria)-École normale supérieure - Rennes (ENS Rennes)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Jim Dowling, François Taïani, TC 6, WG 6.1, Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Design and Implementation of Autonomous Distributed Systems (MYRIADS), Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-SYSTÈMES LARGE ÉCHELLE (IRISA-D1), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), IFIP, European Project: 318521,EC:FP7:ICT,FP7-ICT-2011-8,HARNESS(2012), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Télécom Bretagne-Université de Rennes 1 (UR1), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-École normale supérieure - Rennes (ENS Rennes)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes)
Subjects: Hurst exponent, business.industry, Computer science, Distributed computing, Multi site, 020206 networking & telecommunications, Cloud computing, Failure data, 02 engineering and technology, Predictive failure analysis, [INFO.INFO-NI]Computer Science [cs]/Networking and Internet Architecture [cs.NI], Resource (project management), 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, [INFO]Computer Science [cs], [INFO.INFO-OS]Computer Science [cs]/Operating Systems [cs.OS], business
Abstract: Part 1: Full Research Papers; International audience; Every large multi-site infrastructure such as Grids and Clouds must implement fault-tolerance mechanisms and smart schedulers to enable continuous operation even when resource failures occur. Evaluating the efficiency of such mechanisms and schedulers requires representative failure models that are able to capture realistic properties of real world failure data. This paper shows that failures in multi-site infrastructures are far from being randomly distributed. We propose a failure model that captures features observed in real failure traces.
Published: 2013
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33. Scalable Join Queries in Cloud Data Stores

Author: Guillaume Pierre, Chi-Hung Chi, and Zhou Wei
Subjects: SQL, Database, business.industry, Computer science, Distributed computing, InformationSystems_DATABASEMANAGEMENT, Joins, Cloud computing, computer.software_genre, NoSQL, Middleware (distributed applications), Data integrity, Scalability, Web application, business, computer, computer.programming_language
Abstract: Cloud data stores provide scalability and high availability properties for Web applications, but do not support complex queries such as joins. Web application developers must therefore design their programs according to the peculiarities of No SQL data stores rather than established software engineering practice. This results in complex and error-prone code, especially with respect to subtle issues such as data consistency under concurrent read/write queries. We present join query support in Cloud TPS, a middleware layer which stands between a Web application and its data store. The system enforces strong data consistency and scales linearly under a demanding workload composed of join queries and read-write transactions. In large-scale deployments, Cloud TPS outperforms replicated Postgre SQL up to three times.
Published: 2012
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34. Challenges in very large distributed systems

Author: Maarten van Steen, Spyros Voulgaris, Guillaume Pierre, Computer Science, Computer Systems, Network Institute, and Distributed Computer Systems
Subjects: System of systems, Sociotechnical system, Computer Networks and Communications, Computer science, business.industry, Computer Applications, Distributed computing, Scale (chemistry), Cloud computing, Transparency (human–computer interaction), Computer Science Applications, Scalability, The Internet, business
Abstract: Many modern distributed systems are required to scale in terms of their support for processes, resources, and users. Moreover, a system is often also required to operate across the Internet and across different administrative domains. These scalability requirements lead to a number of well-known challenges in which distribution transparency needs to be traded off against loss of performance. We concentrate on two major challenges for which we claim there is no easy solution. These challenges originate from the fact that users and system are becoming increasingly integrated and are effectively leading us to large-scale socio-technical distributed systems. We identify the design of such integrated systems as one challenge, in particular when it comes to placing humans in the loop as a necessity to proper operation of the system as a whole. As users are so tightly integrated into the overall design, and systems naturally expand through composition, we will be facing problems with respect to long-term management, which we identify as another major challenge.
Published: 2012
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35. ConPaaS: An integrated runtime environment for elastic cloud applications

Author: Corina Stratan, Ismail El Helw, Thilo Kielmann, Ales Cernivec, Jan Stender, Guillaume Pierre, Thorsten Schütt, Matej Artac, and Ana Oprescu
Subjects: Engineering, business.industry, Distributed computing, Real-time computing, 020206 networking & telecommunications, Cloud computing, Content delivery, 02 engineering and technology, On demand, Scalability, 0202 electrical engineering, electronic engineering, information engineering, Web application, 020201 artificial intelligence & image processing, business, Elastic cloud
Abstract: Most Cloud applications are re-enactments of traditional enterprise applications such as Web applications, content delivery and e-commerce [1]. The advantages of the Cloud are well-known: access to a near-infinite number of resources, ability to adjust an application's capacity on demand, pay-as-you-go pricing model. However, Cloud application developers need to pay attention to new topics: building custom VM images, making applications elastic and scalable, controlling performance, fault-tolerance, etc.
Published: 2011
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36. Secure Data Aggregation through Proactive Defense

Author: Shuo Chen, Guillaume Pierre, and Chi-Hung Chi
Subjects: Protocol (science), business.industry, Computer science, Node (networking), Computer security, computer.software_genre, Electronic mail, Data aggregator, Gossip, Convergence (routing), Overhead (computing), business, computer, Computer network
Abstract: Gossip based aggregation protocols are a promising approach to monitoring large-scale decentralized IT infrastructures. Compared to traditional approaches they exhibit good properties of scalability, tolerance of churn, and communication overhead. Gossip-based protocols can compute statistical aggregates such as the average, sum or statistical distribution of an attribute across a large system. However, such protocols are extremely vulnerable to malicious attacks, and even a small number of attackers in the system can largely undermine aggregation results. This paper presents a secure protocol for computing attribute averages. In this system, each node autonomously judges whether its neighbors are malicious, and may subsequently stop any interaction with them. A node appearing malicious to its neighbors quickly gets excluded from the system. Instead of defining malicious behavior (and excluding nodes that follow the definition of maliciousness), our system defines correct behavior (and excludes any node that behaves differently). This allows in principle our system to address arbitrary types of attacks. Simulations based on real-world attribute data demonstrate that our system offers good resistance against four different types of attacks.
Published: 2010
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37. Autonomous resource provisioning for multi-service web applications

Author: Guillaume Pierre, Chi-Hung Chi, and Dejun Jiang
Subjects: Service (business), Resource (project management), business.industry, Computer science, Server, Web application, Provisioning, business, Computer network
Abstract: Dynamic resource provisioning aims at maintaining the end-to-end response time of a web application within a pre-defined SLA. Although the topic has been well studied for monolithic applications, provisioning resources for applications composed of multiple services remains a challenge. When the SLA is violated, one must decide which service(s) should be reprovisioned for optimal effect. We propose to assign an SLA only to the front-end service. Other services are not given any particular response time objectives. Services are autonomously responsible for their own provisioning operations and collaboratively negotiate performance objectives with each other to decide the provisioning service(s). We demonstrate through extensive experiments that our system can add/remove/shift both servers and caches within an entire multi-service application under varying workloads to meet the SLA target and improve resource utilization.
Published: 2010
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38. Enforcing Fairness in Asynchronous Collaborative Environments

Author: M.R. van Steen and Guillaume Pierre
Subjects: Asynchronous communication, business.industry, Computer science, business, Computer network
Abstract: Many large-scale distributed applications rely on collaboration, where unrelated users or organizations share their resources for everyone’s benefit. However, in such environments any node may attempt to maximize its own benefit by exploiting other’s resources without contributing back. Collaborative systems must therefore deploy strategies to fight free-riders, and enforce collaborative behavior. This chapter explores a family of mechanisms to enforce fairness in asynchronous collaborative environments, where simple tit-for-tat policies cannot be used. Our solutions rely on enforced neighborhood relations, where each node is restricted in the choice of other nodes to collaborate with. This creates long-term collaboration relationships, where each node must behave well with its neighbors if it wants to be able to use their resources.
Published: 2010
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39. EC2 Performance Analysis for Resource Provisioning of Service-Oriented Applications

Author: Guillaume Pierre, Jiang Dejun, and Chi-Hung Chi
Subjects: business.industry, Computer science, Distributed computing, Real-time computing, Mean and predicted response, Provisioning, Cloud computing, computer.software_genre, Task (project management), Resource (project management), Virtual machine, Service oriented applications, business, computer
Abstract: Cloud computing is receiving increasingly attention as it provides infinite resource capacity and "pay-as-you-go" resource usage pattern to hosted applications. To maintain its SLA targets, resource provisioning of service-oriented applications in the cloud requires reliable performance from the cloud resources. In this paper, we study performance behavior of small instances in Amazon EC2. We demonstrate that the performance of virtual instances is relatively stable over time with fluctuations of mean response time within at most 8% of the longterm average. Moreover, we also show that different supposedly identical instances often have very different performance, up to a ratio 4 from each other. We consider this as an important issue that must be addressed, but also as an opportunity as it allows one to assign each instance with a task that matches its own performance profile.
Published: 2010
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40. XtreemOS: a Sound Foundation for Cloud Infrastructure and Federations

Author: Christine Morin, Guillaume Pierre, Thilo Kielmann, IBIS (IBIS), Vrije Universiteit Brussel (VUB), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Design and Implementation of Autonomous Distributed Systems (MYRIADS), Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-SYSTÈMES LARGE ÉCHELLE (IRISA-D1), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Desprez, F. and Getov, V. and Priol, T. and Yahyapour, R., European Project: 34259,XTREEMOS, LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), CentraleSupélec-Télécom Bretagne-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National de Recherche en Informatique et en Automatique (Inria)-École normale supérieure - Rennes (ENS Rennes)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Télécom Bretagne-Université de Rennes 1 (UR1), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-École normale supérieure - Rennes (ENS Rennes)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Computer Systems, Network Institute, and High Performance Distributed Computing
Subjects: 020203 distributed computing, Engineering, business.industry, Virtual organization, Distributed computing, 020206 networking & telecommunications, Cloud computing, 02 engineering and technology, computer.software_genre, Grid, Shared resource, Resource (project management), federation, Mobile IP, Virtual machine, Resource isolation, 0202 electrical engineering, electronic engineering, information engineering, [INFO.INFO-OS]Computer Science [cs]/Operating Systems [cs.OS], virtual organization, business, computer, Cloud
Abstract: International audience; XtreemOS is a Linux-based operating system with native support for virtual organizations (VO's), for building large-scale resource federations. XtreemOS has been designed as a grid operating system, supporting the model of resource sharing among independent administrative domains. We argue, however, that the VO concept can be used to establish either resource sharing or resource isolation, or even both at the same time. We outline XtreemOS' fundamental properties and how its native VO support can be used to implement cloud infrastructure and cloud federations.
Published: 2010
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41. Autonomous Resource Selection for Decentralized Utility Computing

Author: Paolo Costa, Maarten van Steen, Jeff Napper, and Guillaume Pierre
Subjects: Software, Resource (project management), Utility computing, Computer science, business.industry, Distributed computing, Node (networking), Scalability, Resource allocation, business, Selection (genetic algorithm)
Abstract: Many large-scale utility computing infrastructures comprise heterogeneous hardware and software resources. This raises the need for scalable resource selection services, which identify resources that match application requirements, and can potentially be assigned to these applications. We present a fully decentralized resource selection algorithm by which resources autonomously select themselves when their attributes match a query. An application specifies what it expects from a resource by means of a conjunction of (attribute, value-range) pairs, which are matched against the attribute values of resources. We show that our solution scales in the number of resources as well as in the number of attributes, while being relatively insensitive to churn and other membership changes such as node failures.
Published: 2009
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42. Highly available and scalable grid services

Author: Thorsten Schütt, Jörg Domaschka, Massimo Coppola, and Guillaume Pierre
Subjects: Open Source, Database, Data grid, Computer science, business.industry, Operating Systems, Linux, Scale (chemistry), Distributed computing, Data management, computer.software_genre, Grid, Virtual Organizations, Semantic grid, Grid computing, Scalability, business, computer
Abstract: Researchers who build Grid computing infrastructures constantly face scalability issues, both at the system-level of the Grid's internals and at the user-level to support complex end-user applications. XtreemOS is an E.U. research project that aims at "Building and Promoting a Linux-based Operating System to Support Virtual Organizations for Next Generation Grids". One of the explicit goals of the project is to address scalability issues by abstracting these issues as much as possible from the internal implementation of the system. This is an ambitious goal, since in the most general case scalability issues must be addressed within each component of a distributed system. To a certain extent, it is possible to build scalable abstractions that allow other programmers to build system-level and application-level functionalities while giving less thought to scalability issues. This paper discusses a number of highly available and scalable Grid services that are being built to support this idea. They can be classified in three separate categories: (i) services to store/query structured data in a scalable fashion; (ii) services to communicate in a scalable fashion; (iii) services to (partially) hide the effects of scale.
Published: 2009
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43. Wikipedia Workload Analysis for Decentralized Hosting

Author: Guillaume Pierre, Guido Urdaneta, Maarten van Steen, Computer Systems, Network Institute, and Distributed Computer Systems
Subjects: Computer Networks and Communications, Computer science, Hosting environment, business.industry, Distributed computing, Workload, Peer-to-peer, computer.software_genre, Replication (computing), Shared resource, Consistency (database systems), business, computer, TRACE (psycholinguistics), Computer network
Abstract: We study an access trace containing a sample of Wikipedia's traffic over a 107-day period aiming to identify appropriate replication and distribution strategies in a fully decentralized hosting environment. We perform a global analysis of the whole trace, and a detailed analysis of the requests directed to the English edition of Wikipedia. In our study, we classify client requests and examine aspects such as the number of read and save operations, significant load variations and requests for nonexisting pages. We also review proposed decentralized wiki architectures and discuss how they would handle Wikipedia's workload. We conclude that decentralized architectures must focus on applying techniques to efficiently handle read operations while maintaining consistency and dealing with typical issues on decentralized systems such as churn, unbalanced loads and malicious participating nodes. © 2009 Elsevier B.V. All rights reserved.
Published: 2009
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44. Scalable Transactions for Web Applications in the Cloud

Author: Guillaume Pierre, Chi-Hung Chi, and Zhou Wei
Subjects: Computer science, business.industry, Distributed computing, Cloud computing, Transactions per second, High availability, Cloud testing, Scalability, Distributed transaction, Online transaction processing, Web application, Cloud database, business, Database transaction
Abstract: Cloud computing platforms provide scalability and high availability properties for web applications but they sacrifice data consistency at the same time. However, many applications cannot afford any data inconsistency. We present a scalable transaction manager for cloud database services to execute ACID transactions of web applications, even in the presence of server failures. We demonstrate the scalability of our system using a prototype implementation, and show that it scales linearly to at least 40 nodes sustaining a maximum throughput of 7286 transactions per second.
Published: 2009
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45. On the Feasibility of Decentralized Grid Scheduling

Author: Guillaume Pierre, Paolo Costa, M. Fiscato, Computer Systems, and Distributed Computer Systems
Subjects: Grid scheduling, Schedule, business.industry, Computer science, Distributed computing, Processor scheduling, Grid resource management, computer.software_genre, Fair-share scheduling, Scheduling (computing), Grid computing, Scalability, business, computer, Computer network
Abstract: Many authors recognize the limitations of hierarchical Grid scheduling in scalable environments, and proposed peer-to-peer solutions to this problem. However, most peer-to-peer grid resource management systems allow only to discover available resources at the time of the request. We claim that peer-to-peer techniques have the potential for actual Grid scheduling, where each resource maintains a schedule of its future allocation to jobs. We present such a protocol, which additionally allows users to specify desired properties about the requested schedules.
Published: 2008
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46. Service-oriented data denormalization for scalable web applications

Author: Chi-Hung Chi, Guillaume Pierre, Jiang Dejun, Zhou Wei, and Maarten van Steen
Subjects: Database, business.industry, Restructuring, Process (engineering), Computer science, computer.software_genre, Database design, Denormalization, Replication (computing), Data store, Scalability, Benchmark (computing), Web application, business, Throughput (business), computer
Abstract: Many techniques have been proposed to scale web applications. However, the data interdependencies between the database queries and transactions issued by the applications limit their efficiency. We claim that major scalability improvements can be gained by restructuring the web application data into multiple independent data services with exclusive access to their private data store. While this restructuring does not provide performance gains by itself, the implied simplification of each database workload allows a much more efficient use of classical techniques. We illustrate the data denormalization process on three benchmark applications: TPC-W, RUBiS and RUBBoS. We deploy the resulting service-oriented implementation of TPC-W across an 85-node cluster and show that restructuring its data can provide at least an order of magnitude improvement in the maximum sustainable throughput compared to master-slave database replication, while preserving strong consistency and transactional properties.
Published: 2008
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47. Practical Large-Scale Latency Estimation

Author: Guillaume Pierre, Michal Szymaniak, Maarten van Steen, David Presotto, Computer Systems, and Distributed Computer Systems
Subjects: Computer Networks and Communications, business.industry, Computer science, Scalability, Real-time computing, Content delivery network, The Internet, Latency (engineering), business, Scheduling (computing)
Abstract: We present the implementation of a large-scale latency estimation system based on GNP and incorporated into the Google content delivery network. Our implementation employs standard features of contemporary Web clients, and carefully controls the overhead incurred by latency measurements using a scalable centralized scheduler. It also requires only a small number of CDN modifications, which makes it attractive for any CDN interested in large-scale latency estimation. We investigate the issue of coordinate stability over time and show that coordinates drift away from their initial values with time, so that 25% of node coordinates become inaccurate by more than 33 ms after one week. However, daily re-computations make 75% of the coordinates stay within 6 ms of their initial values. Furthermore, we demonstrate that using coordinates to decide on client-to-replica re-direction leads to selecting replicas closest in term of measured latency in 86% of all cases. In another 10% of all cases, clients are re-directed to replicas offering latencies that are at most two times longer than optimal. Finally, collecting a huge volume of latency data and using clustering techniques enable us to estimate latencies between globally distributed Internet hosts that have not participated in our measurements at all. The results are sufficiently promising that Google may offer a public interface to the latency estimates in the future. © 2008 Elsevier B.V. All rights reserved.
Published: 2008
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48. Analysis of Caching and Replication Strategies for Web Applications

Author: Guillaume Pierre, Gustavo Alonso, Swaminathan Sivasubramanian, M. van Steen, Computer Systems, and Distributed Computer Systems
Subjects: Web server, Computer Networks and Communications, business.industry, Computer science, Distributed computing, computer.software_genre, Application software, Replication (computing), World Wide Web, Web page, Web cache, Web application, The Internet, Web service, business, computer
Abstract: Developers often use replication and caching mechanisms to enhance Web application performance. The authors present a qualitative and quantitative analysis of state-of-the art replication and caching techniques used to host Web applications. Their analysis shows that selecting the best mechanism depends heavily on data workload and requires a careful review of the application's characteristics. They also propose a technique for Web practitioners to compare different mechanisms' performance on their own. © 2007 IEEE.
Published: 2007
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49. High Availability and Scalability Support for Web Applications

Author: Swaminathan Sivasubramanian, L. Rilling, Guillaume Pierre, Computer Systems, and Distributed Computer Systems
Subjects: Web search query, Application server, Computer science, business.industry, Distributed computing, computer.software_genre, Web API, Client–server model, Web query classification, Server, High availability, Web service, business, computer, Computer network
Abstract: A database query caching technique, GlobeCBC, can be used to improve the scalability of Web applications. This paper addresses the availability issues in GlobeCBC. Even though high availability is achieved by adding more resources, proper algorithms must be designed to ensure that the clients receive consistent responses amidst failures of the edge and origin servers. We present lightweight algorithms to detect and correct server failures while providing read-your-writes consistency. They exploit the fact that the query workload of Web applications is based on a fixed set of read and write templates. We show that these algorithms incur very low overhead using several microbenchmarks and a complete Web application benchmark
Published: 2007

50. GlobeTP: Template-Based Database Replication for Scalable Web Applications

Author: Guillaume Pierre, Swaminathan Sivasubramanian, Tobias Groothuyse, Computer Systems, and Distributed Computer Systems
Subjects: Computer science, View, business.industry, Replica, Distributed computing, Replication (computing), Database tuning, Server, Scalability, Table (database), Web application, Cache, business, Throughput (business)
Abstract: Generic database replication algorithms do not scale linearly in throughput as all update, deletion and insertion (UDI) queries must be applied to every database replica. The throughput is therefore limited to the point where the number of UDI queries alone is sufficient to overload one server. In such scenarios, partial replication of a database can help, as UDI queries are executed only by a subset of all servers. In this paper we propose GlobeTP, a system that employs partial replication to improve database throughput. GlobeTP exploits the fact that a Web application's query workload is composed of a small set of read and write templates. Using knowledge of these templates and their respective execution costs, GlobeTP provides database table placements that produce significant improvements in database throughput. We demonstrate the efficiency of this technique using two different industry standard benchmarks. In our experiments, GlobeTP increases the throughput by 57% to 150% compared to full replication, while using identical hardware configuration. Furthermore, adding a single query cache improves the throughput by another 30% to 60%.
Published: 2007

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