Graphic summary
  • Show / hide key
  • Information


Scientific and technological production
  •  

1 to 50 of 116 results
  • Business-driven management of infrastructure-level risks in Cloud providers

     Fitó Comellas, Josep Oriol; Guitart Fernández, Jordi
    Future generation computer systems
    Date of publication: 2014-03-01
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Cloud computing is an innovative and promising paradigm that is leading to remarkable changes in the way in which hardware and software are designed and purchased, as well as how IT systems are managed. However, the Cloud is a risky paradigm. For instance, the use of Cloud services, which usually are external assets to their consumers, implies unprecedented risks that must be taken into account.; In this paper, we propose the involvement of the risk management discipline into the Cloud computing realm. We present a risk management approach led by business-level objectives (BLOs) of Cloud organizations. Its main goal is to assist in business-driven self-managed Cloud providers, by facing uncertainties always present in their internal decision-making processes. Our Cloud-aware risk management method includes a SEmi-quantitative BLO-driven Cloud Risk Assessment (SEBCRA) as the core subprocess. Its aim is to constantly rank and prioritize risks affecting the governing business-level goals.; In addition, we present, as a use case, a PaaS provider that incorporates our risk management approach to enhance the achievement of two BLOs, i.e. maximization of profit and customer satisfaction. In particular, it can manage - identify, assess, and treat - the most critical Cloud infrastructure-level risks, i.e. provisioning its private Cloud, either under- or over-provisioning, as well as resource failures. We present some risk treatment responses to face these risks and we evaluate their impact on the above-mentioned BLOs. Our results show that the best responses to address risks may change over time depending on the current provider's status. As a result, an adaptive management of risks should be considered as a mandatory process for Cloud providers to ensure their success in the ever-growing worldwide ecosystem of Clouds. (C) 2012 Elsevier B.V. All rights reserved.

  • Risk-driven proactive fault-tolerant operation of IaaS providers

     Guitart Fernández, Jordi; Macias Lloret, Mario; Djemame, Karim; Kirkham, Thomas; Jiang, Ming; Armstrong, Django
    IEEE International Conference on Cloud Computing Technology and Science
    Presentation's date: 2013-12-02
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    In order to improve service execution in Clouds, the management of Cloud Infrastructure has to take measures to adhere to Service Level Agreements and Business Level Objectives, from the application layer through to how services are supported at the lowest hardware levels. In this paper a risk model methodology and holistic management approach is developed specific to the operation of the Cloud Infrastructure Provider and is applied through improvements to SLA fault tolerance in Cloud Infrastructure. Risk assessments are used to analyse execution specific data from the Cloud Infrastructure and linked to a business driven holistic management component that is part of a Cloud Manager. Initial results show improved eco-efficiency, virtual machine availability and reductions in SLA failure across the whole Cloud infrastructure by applying our combined risk-based fault tolerance approach.

  • A service framework for energy-aware monitoring and VM management in clouds

     Katsaros, Gregory; Subirats, Josep; Fitó Comellas, Josep Oriol; Guitart Fernández, Jordi; Gilet, Pierre; Espling, Daniel
    Future generation computer systems
    Date of publication: 2013-10
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    The monitoring of QoS parameters in Services Computing as well as in Clouds has been a functionality provided by all contemporary systems. As the optimization of energy consumption becomes a major concern for system designers and administrators, it can be considered as another QoS metric to be monitored. In this paper, we present a service framework that allows us to monitor the energy consumption of a Cloud infrastructure, calculate its energy efficiency, and evaluate the gathered data in order to put in place an effective virtual machine (VM) management. In that context, a simulation scenario of an eco-driven VM placement policy resulted in a 14% improvement of the infrastructure¿s energy efficiency. In total, the proposed approaches and implementations have been validated against a testbed, producing very promising results regarding the prospect of energy efficiency as an important quality factor in Clouds.

  • EMOTIVE cloud: the BSC's IaaS open source solution for cloud computing

     Vaqué, Alex; Goiri Presa, Iñigo; Guitart Fernández, Jordi; Torres Viñals, Jordi
    Date of publication: 2012-01
    Book chapter

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Toward energy-aware scheduling using machine learning

     Berral Garcia, Josep Lluis; Goiri Presa, Iñigo; Nou Castell, Ramon; Julià Massó, Ferran; Fitó Comellas, Josep Oriol; Guitart Fernández, Jordi; Gavaldà Mestre, Ricard; Torres Viñals, Jordi
    Date of publication: 2012-07-30
    Book chapter

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • On the anticipation of resource demands to fulfill the QoS of SaaS web applications

     Reig Ventura, Gemma; Guitart Fernández, Jordi
    ACM/IEEE International Conference on Grid Computing
    Presentation's date: 2012-09-20
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Cheat-proof trust model for cloud computing markets

     Macias Lloret, Mario; Guitart Fernández, Jordi
    International Conference on Economics of Grids, Clouds, Systems and Services
    Presentation's date: 2012-11-28
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • GreenHadoop: leveraging green energy in data-processing frameworks

     Goiri, Iñigo; Le, Kien; Nguyen, Thu D.; Guitart Fernández, Jordi; Torres Viñals, Jordi; Bianchini, Ricardo
    ACM European Conference on Computer Systems
    Presentation's date: 2012-04-10
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Business-driven IT management for cloud computing providers

     Fitó Comellas, Josep Oriol; Macias Lloret, Mario; Julià Massó, Ferran; Guitart Fernández, Jordi
    International Conference on Cloud Computing Technology and Science
    Presentation's date: 2012-12-03
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Client classification policies for SLA enforcement in shared cloud datacenters

     Macias Lloret, Mario; Guitart Fernández, Jordi
    IEEE/ACM International Symposium on Cluster, Cloud and Grid Computing
    Presentation's date: 2012-05-13
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Supporting CPU-based guarantees in cloud SLAs via resource-level QoS metrics

     Goiri Presa, Iñigo; Julià Masso, Ferran; Fitó Comellas, Josep Oriol; Macias Lloret, Mario; Guitart Fernández, Jordi
    Future generation computer systems
    Date of publication: 2012-10
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Success of Cloud computing requires that both customers and providers can be confident that signed Service Level Agreements (SLA) are supporting their respective business activities to their best extent. Currently used SLAs fail in providing such confidence, especially when providers outsource resources to other providers. These resource providers typically support very simple metrics like availability, or metrics that hinder an efficient exploitation of their resources. In this paper, we propose a resource-level metric for specifying fine-grain guarantees on CPU performance. This metric allows resource providers to allocate dynamically their resources among running services depending on their demand. This is accomplished by incorporating the customer’s CPU usage in the metric definition, but avoiding fake SLA violations when the customer’s task does not use all its allocated resources. We have conducted the evaluation in a virtualized provider where we have implemented the needed infrastructure for using our metric. As demonstrated in our evaluation, our solution presents fewer SLA violations than other CPU-related metrics while maintaining the Quality of Service.

  • OPTIMIS: A holistic approach to cloud service provisioning

     Juan, Ana; Hernández, Francisco; Tordsson, Johan; Elmroth, Erik; Ali-Eldin, Ahmed; Zsigri, Csilla; Sirvent Pardell, Raül; Guitart Fernández, Jordi; Badia Sala, Rosa Maria; Djemame, Karim; Ziegler, Wolfgang; Dimitrakos, Theo; Nair, Srijith K.; Kousiouris, George; Konstanteli, Kleopatra; Varvarigou, Theodora; Hudzia, Benoit; Kipp, Alexander; Wesner, Stefan; Corrales, Marcelo; Forgó, Nikolaus; Sharif, Tabassum; Sheridan, Craig
    Future generation computer systems
    Date of publication: 2012-01
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    We present fundamental challenges for scalable and dependable service platforms and architectures that enable flexible and dynamic provisioning of cloud services. Our findings are incorporated in a toolkit targeting the cloud service and infrastructure providers. The innovations behind the toolkit are aimed at optimizing the whole service life cycle, including service construction, deployment, and operation, on a basis of aspects such as trust, risk, eco-efficiency and cost. Notably, adaptive self-preservation is crucial to meet predicted and unforeseen changes in resource requirements. By addressing the whole service life cycle, taking into account several cloud architectures, and by taking a holistic approach to sustainable service provisioning, the toolkit aims to provide a foundation for a reliable, sustainable, and trustful cloud computing industry.

  • Economic model of a cloud provider operating in a federated cloud

     Goiri Presa, Iñigo; Guitart Fernández, Jordi; Torres Viñals, Jordi
    Information systems frontiers
    Date of publication: 2012-09
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Resource provisioning in Cloud providers is a challenge because of the high variability of load over time. On the one hand, the providers can serve most of the requests owning only a restricted amount of resources, but this forces to reject customers during peak hours. On the other hand, valley hours incur in under-utilization of the resources, which forces the providers to increase their prices to be profitable. Federation overcomes these limitations and allows providers to dynamically outsource resources to others in response to demand variations. Furthermore, it allows providers with underused resources to rent them to other providers. Both techniques make the provider getting more profit when used adequately. Federation of Cloud providers requires having a clear understanding of the consequences of each decision. In this paper, we present a characterization of providers operating in a federated Cloud which helps to choose the most convenient decision depending on the environment conditions. These include when to outsource to other providers, rent free resources to other providers (i.e., insourcing), or turn off unused nodes to save power. We characterize these decisions as a function of several parameters and implement a federated provider that uses this characterization to exploit federation. Finally, we evaluate the profitability of using these techniques using the data from a real provider.

  • Energy-efficient and multifaceted resource management for profit-driven virtualized data centers

     Goiri, Iñigo; Berral Garcia, Josep Lluis; Fitó Comellas, Josep Oriol; Julià Massó, Ferran; Nou Castell, Ramon; Guitart Fernández, Jordi; Gavaldà Mestre, Ricard; Torres Viñals, Jordi
    Future generation computer systems
    Date of publication: 2012-05
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    As long as virtualization has been introduced in data centers, it has been opening new chances for resource management. Nowadays, it is not just used as a tool for consolidating underused nodes and save power; it also allows new solutions to well-known challenges, such as heterogeneity management. Virtualization helps to encapsulate Web-based applications or HPC jobs in virtual machines (VMs) and see them as a single entity which can be managed in an easier and more efficient way. We propose a new scheduling policy that models and manages a virtualized data center. It focuses on the allocation of VMs in data center nodes according to multiple facets to optimize the provider’s profit. In particular, it considers energy efficiency, virtualization overheads, and SLA violation penalties, and supports the outsourcing to external providers. The proposed approach is compared to other common scheduling policies, demonstrating that a provider can improve its benefit by 30% and save power while handling other challenges, such as resource outsourcing, in a better and more intuitive way than other typical approaches do.

    Postprint (author’s final draft)

  • A genetic model for pricing in cloud computing markets

     Macias Lloret, Mario; Guitart Fernández, Jordi
    ACM Symposium on Applied Computing
    Presentation's date: 2011-03-21
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Access to the full text
    Client classification policies for SLA negotiation and allocation in shared cloud datacenters  Open access

     Macias Lloret, Mario; Guitart Fernández, Jordi
    International Conference on the Economics of Grids, Clouds, Systems, and Services
    Presentation's date: 2011-12-05
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    In Utility Computing business model, the owners of the computing resources negotiate with their potential clients to sell computing power. The terms of the Quality of Service (QoS) to be provided as well as the economic conditions are established in a Service-Level Agreement (SLA). There are situations in which providers must differentiate the SLAs in function of the type of Client that is willing to access the resources or the agreed QoS e.g. when the hardware resources are shared between users of the company that own the resources and external users. This paper proposes to consider the information of potential users when the SLA is under negotiation to allow providers to prioritize users (e.g. internal users over external users, or preferential users over common users). Two policies for negotiation are introduced: price discrimination and client-aware overselling of resources. The validity of the policies is demonstrated through exhaustive experiments.

    Postprint (author’s final draft)

  • Demonstration of the OPTIMIS toolkit for cloud service provisioning

     Badia Sala, Rosa Maria; Corrales, Marcelo; Dimitrakos, Theo; Djemame, Karim; Elmroth, Erik; Juan Ferrer, Ana; Forgó, Nikolaus; Guitart Fernández, Jordi; Hernández, Francisco; Hudzia, Benoit; Kipp, Alexander; Konstanteli, Kleopatra; Kousiouris, George; Nair, Srijith K.; Sharif, Tabassum; Sheridan, Craig; Sirvent Pardell, Raül; Tordsson, Johan; Varvarigou, Theodora; Wesner, Stefan; Ziegler, Wolfgang; Zsigri, Csilla
    ServiceWave Conference Series
    Presentation's date: 2011
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • GreenSlot: scheduling energy consumption in green datacenters

     Goiri Presa, Iñigo; Le, Kien; Haque, Md. E.; Beauchea, Ryan; Nguyen, Thu D.; Guitart Fernández, Jordi; Torres Viñals, Jordi; Bianchini, Ricardo
    International Conference for High Performance Computing, Networking, Storage and Analysis
    Presentation's date: 2011-11-16
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Optimal resource allocation in a virtualized software aging platform with software rejuvenation

     Alonso López, Javier; Goiri Presa, Iñigo; Guitart Fernández, Jordi; Gavaldà Mestre, Ricard; Torres Viñals, Jordi
    IEEE International Symposium on Software Reliability Engineering
    Presentation's date: 2011-11-29
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Intelligent placement of datacenters for Internet services

     Goiri Presa, Iñigo; Le, Kien; Guitart Fernández, Jordi; Torres Viñals, Jordi; Bianchini, Ricardo
    International Conference on Distributed Computing Systems
    Presentation's date: 2011-06-20
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Towards sustainable solutions for European cloud computing

     Le, Kien; Nguyen, Thu D.; Goiri, Iñigo; Bianchini, Ricardo; Guitart Fernández, Jordi; Torres Viñals, Jordi
    Upgrade
    Date of publication: 2011-10
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Multifaceted Resource Management on Virtualized Providers  Open access

     Goiri Presa, Iñigo
    Defense's date: 2011-06-14
    Department of Computer Architecture, Universitat Politècnica de Catalunya
    Theses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    Last decade, providers started using Virtual Machines (VMs) in their datacenters to pack users and their applications. This was a good way to consolidate multiple users in fewer physical nodes while isolating them from each other. Later on in 2006, Amazon started offering their Infrastructure as a Service where their users rent computing resources as VMs in a pay-as-you-go manner. However, virtualized providers cannot be managed like traditional ones as they are now confronted with a set of new challenges. First of all, providers must deal efficiently with new management operations such as the dynamic creation of VMs. These operations enable new capabilities that were not there before, such as moving VMs across the nodes, or the ability to checkpoint VMs. We propose a Decentralized virtualization management infrastructure to create VMs on demand, migrate them between nodes, and checkpointing mechanisms. With the introduction of this infrastructure, virtualized providers become decentralized and are able to scale. Secondly, these providers consolidate multiple VMs in a single machine to more efficiently utilize resources. Nevertheless, this is not straightforward and implies the use of more complex resource management techniques. In addition, this requires that both customers and providers can be confident that signed Service Level Agreements (SLAs) are supporting their respective business activities to their best extent. Providers typically offer very simple metrics that hinder an efficient exploitation of their resources. To solve this, we propose mechanisms to dynamically distribute resources among VMs and a resource-level metric, which together allow increasing provider utilization while maintaining Quality of Service. Thirdly, the provider must allocate the VMs evaluating multiple facets such as power consumption and customers' requirements. In addition, it must exploit the new capabilities introduced by virtualization and manage its overhead. Ultimately, this VM placement must minimize the costs associated with the execution of a VM in a provider to maximize the provider's profit. We propose a new scheduling policy that places VMs on provider nodes according to multiple facets and is able to understand and manage the overheads of dealing with virtualization. And fourthly, resource provisioning in these providers is a challenge because of the high load variability over time. Providers can serve most of the requests owning only a restricted amount of resources but this under-provisioning may cause customers to be rejected during peak hours. In the opposite situation, valley hours incur under-utilization of the resources. As this new paradigm makes the access to resources easier, providers can share resources to serve their loads. We leverage a federated scenario where multiple providers share their resources to overcome this load variability. We exploit the federation capabilities to create policies that take the most convenient decision depending on the environment conditions and tackle the load variability. All these challenges mean that providers must manage their virtualized resources in a different way than they have done traditionally. This dissertation identifies and studies the challenges faced by virtualized provider that offers IaaS, and designs and evaluates a solution to manage the provider's resources in the most cost-effective way by exploiting the virtualization capabilities.

  • A MIDDLEWARE FRAMEWORK FOR SELF-ADAPTIVE LARGE SCALE DISTRIBUTED SERVICES  Open access

     Chacin Martinez, Pablo Jesus
    Defense's date: 2011-07-21
    Department of Computer Architecture, Universitat Politècnica de Catalunya
    Theses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    Modern service-oriented applications demand the ability to adapt to changing conditions and unexpected situations while maintaining a required QoS. Existing self-adaptation approaches seem inadequate to address this challenge because many of their assumptions are not met on the large-scale, highly dynamic infrastructures where these applications are generally deployed on. The main motivation of our research is to devise principles that guide the construction of large scale self-adaptive distributed services. We aim to provide sound modeling abstractions based on a clear conceptual background, and their realization as a middleware framework that supports the development of such services. Taking the inspiration from the concepts of decentralized markets in economics, we propose a solution based on three principles: emergent self-organization, utility driven behavior and model-less adaptation. Based on these principles, we designed Collectives, a middleware framework which provides a comprehensive solution for the diverse adaptation concerns that rise in the development of distributed systems. We tested the soundness and comprehensiveness of the Collectives framework by implementing eUDON, a middleware for self-adaptive web services, which we then evaluated extensively by means of a simulation model to analyze its adaptation capabilities in diverse settings. We found that eUDON exhibits the intended properties: it adapts to diverse conditions like peaks in the workload and massive failures, maintaining its QoS and using efficiently the available resources; it is highly scalable and robust; can be implemented on existing services in a non-intrusive way; and do not require any performance model of the services, their workload or the resources they use. We can conclude that our work proposes a solution for the requirements of self-adaptation in demanding usage scenarios without introducing additional complexity. In that sense, we believe we make a significant contribution towards the development of future generation service-oriented applications.

    Las Aplicaciones Orientadas a Servicios modernas demandan la capacidad de adaptarse a condiciones variables y situaciones inesperadas mientras mantienen un cierto nivel de servio esperado (QoS). Los enfoques de auto-adaptación existentes parecen no ser adacuados debido a sus supuestos no se cumplen en infrastructuras compartidas de gran escala. La principal motivación de nuestra investigación es inerir un conjunto de principios para guiar el desarrollo de servicios auto-adaptativos de gran escala. Nuesto objetivo es proveer abstraciones de modelaje apropiadas, basadas en un marco conceptual claro, y su implemetnacion en un middleware que soporte el desarrollo de estos servicios. Tomando como inspiración conceptos económicos de mercados decentralizados, hemos propuesto una solución basada en tres principios: auto-organización emergente, comportamiento guiado por la utilidad y adaptación sin modelos. Basados en estos principios diseñamos Collectives, un middleware que proveer una solución exhaustiva para los diversos aspectos de adaptación que surgen en el desarrollo de sistemas distribuidos. La adecuación y completitud de Collectives ha sido provada por medio de la implementación de eUDON, un middleware para servicios auto-adaptativos, el ha sido evaluado de manera exhaustiva por medio de un modelo de simulación, analizando sus propiedades de adaptación en diversos escenarios de uso. Hemos encontrado que eUDON exhibe las propiedades esperadas: se adapta a diversas condiciones como picos en la carga de trabajo o fallos masivos, mateniendo su calidad de servicio y haciendo un uso eficiente de los recusos disponibles. Es altamente escalable y robusto; puedeoo ser implementado en servicios existentes de manera no intrusiva; y no requiere la obtención de un modelo de desempeño para los servicios. Podemos concluir que nuestro trabajo nos ha permitido desarrollar una solucion que aborda los requerimientos de auto-adaptacion en escenarios de uso exigentes sin introducir complejidad adicional. En este sentido, consideramos que nuestra propuesta hace una contribución significativa hacia el desarrollo de la futura generación de aplicaciones orientadas a servicios.

  • Access to the full text
    Checkpoint-based fault-tolerant infrastructure for virtualized service providers  Open access

     Goiri Presa, Iñigo; Julià, Ferran; Guitart Fernández, Jordi; Torres Viñals, Jordi
    IEEE/ IFIP Network Operations and management Symposium
    Presentation's date: 2010-04-19
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    Crash and omission failures are common in service providers: a disk can break down or a link can fail anytime. In addition, the probability of a node failure increases with the number of nodes. Apart from reducing the provider’s computation power and jeopardizing the fulfillment of his contracts, this can also lead to computation time wasting when the crash occurs before finishing the task execution. In order to avoid this problem, efficient checkpoint infrastructures are required, especially in virtualized environments where these infrastructures must deal with huge virtual machine images. This paper proposes a smart checkpoint infrastructure for virtualized service providers. It uses Another Union File System to differentiate read-only from read-write parts in the virtual machine image. In this way, read-only parts can be checkpointed only once, while the rest of checkpoints must only save the modifications in read-write parts, thus reducing the time needed to make a checkpoint. The checkpoints are stored in a Hadoop Distributed File System. This allows resuming a task execution faster after a node crash and increasing the fault tolerance of the system, since checkpoints are distributed and replicated in all the nodes of the provider. This paper presents a running implementation of this infrastructure and its evaluation, demonstrating that it is an effective way to make faster checkpoints with low interference on task execution and efficient task recovery after a node failure.

  • Access to the full text
    Multifaceted resource management for dealing with heterogeneous workloads in virtualized data centers  Open access

     Goiri Presa, Iñigo; Fitó Comellas, Josep Oriol; Julià Masso, Ferran; Nou Castell, Ramon; Berral Garcia, Josep Lluis; Guitart Fernández, Jordi; Torres Viñals, Jordi
    ACM/IEEE International Conference on Grid Computing
    Presentation's date: 2010-10-25
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    As long as virtualization has been introduced in data centers, it has been opening new chances for resource management. Now, it is not just used as a tool for consolidating underused nodes and save power, it also allows new solutions to well-known challenges, such as fault tolerance or heterogeneity management. Virtualization helps to encapsulate Web-based applications or HPC jobs in virtual machines and see them as a single entity which can be managed in an easier way. This paper proposes a new scheduling policy to model and manage a virtualized data center which mainly focuses on the allocation of VMs in data center nodes according to multiple facets while optimizing the provider’s profit. In particular, it considers energy efficiency, virtualization overheads, fault tolerance, and SLA violation penalties, while adding the ability to outsource resources to external providers. Using our approach, a data center can improve the provider’s benefit by 15% and get a power reduction while solving well-known challenges, such as fault tolerance and outsourcing, in a better a more intuitive way that typical approaches do.

  • Access to the full text
    Characterizing cloud federation for enhancing providers' profit  Open access

     Goiri Presa, Iñigo; Guitart Fernández, Jordi; Torres Viñals, Jordi
    IEEE International Conference on Cloud Computing Technology and Science
    Presentation's date: 2010-07-05
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    Cloud federation has been proposed as a new paradigm that allows providers to avoid the limitation of owning only a restricted amount of resources, which forces them to reject new customers when they have not enough local resources to fulfill their customers’ requirements. Federation allows a provider to dynamically outsource resources to other providers in response to demand variations. It also allows a provider that has underused resources to rent part of them to other providers. Both things could make the provider to get more profit when used adequately. This requires that the provider has a clear understanding of the potential of each federation decision, in order to choose the most convenient depending on the environment conditions. In this paper, we present a complete characterization of providers’ federation in the Cloud, including decision equations to outsource resources to other providers, rent free resources to other providers (i.e. insourcing), or shutdown unused nodes to save power, and we characterize these decisions as a function of several parameters. Then, we demonstrate in the evaluation section how a provider can enhance its profit by using these equations to exploit federation, and how the different parameters influence which is the best decision on each situation.

  • Access to the full text
    BSC contributions in energy-aware resource management for large scale distributed systems  Open access

     Torres Viñals, Jordi; Ayguade Parra, Eduard; Carrera Perez, David; Guitart Fernández, Jordi; Beltran Querol, Vicenç; Becerra Fontal, Yolanda; Badia Sala, Rosa Maria; Labarta Mancho, Jesus Jose; Valero Cortes, Mateo
    Workshop of the COST Action IC0804 on Energy Efficiency in Large Scale Distributed Systems
    Presentation's date: 2010-04-15
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    This paper introduces the work being carried out at Barcelona Supercomputing Center in the area of Green Computing. We have been working in resource management for a long time and recently we included the energy parameter in the decision process, considering that for a more sustainable science, the paradigm will shift from “time to solution” to “kWh to the solution”. We will present our proposals organized in four points that follow the cloud computing stack. For each point we will enumerate the latest achievements that will be published during 2010 that are the basics for our future research. To conclude the paper we will review our ongoing and future research work and an overview of the projects where BSC is participating.

  • Access to the full text
    Energy-aware scheduling in virtualized datacenters  Open access

     Goiri Presa, Iñigo; Julià Massó, Ferran; Nou Castell, Ramon; Berral Garcia, Josep Lluis; Guitart Fernández, Jordi; Torres Viñals, Jordi
    IEEE International Conference on Cluster Computing
    Presentation's date: 2010-09-20
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    The reduction of energy consumption in large-scale datacenters is being accomplished through an extensive use of virtualization, which enables the consolidation of multiple workloads in a smaller number of machines. Nevertheless, virtualization also incurs some additional overheads (e.g. virtual machine creation and migration) that can influence what is the best consolidated configuration, and thus, they must be taken into account. In this paper, we present a dynamic job scheduling policy for power-aware resource allocation in a virtualized datacenter. Our policy tries to consolidate workloads from separate machines into a smaller number of nodes, while fulfilling the amount of hardware resources needed to preserve the quality of service of each job. This allows turning off the spare servers, thus reducing the overall datacenter power consumption. As a novelty, this policy incorporates all the virtualization overheads in the decision process. In addition, our policy is prepared to consider other important parameters for a datacenter, such as reliability or dynamic SLA enforcement, in a synergistic way with power consumption. The introduced policy is evaluated comparing it against common policies in a simulated environment that accurately models HPC jobs execution in a virtualized datacenter including power consumption modeling and obtains a power consumption reduction of 15% with respect to typical policies.

  • Access to the full text
    Using resource-level information into nonadditive negotiation models for cloud market environments  Open access

     Macias Lloret, Mario; Guitart Fernández, Jordi
    IEEE/ IFIP Network Operations and management Symposium
    Presentation's date: 2010-04-19
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    Markets arise as an efficient way of organising resources in Cloud Computing scenarios. In Cloud Computing Markets, Brokers that represent both Clients and Service Providers meet in a Market and negotiate for the sales of resources or services. This paper defends the idea that efficient negotiations require of the usage of resource-level information for increasing the accuracy of negotiated Service Level Agreements and facilitating the achievement of both performance and business goals. A negotiation model based on the maximisation of nonadditive utility functions that considers multiple objectives is defined, and its validity is demonstrated in the experiments.

  • Toward business-driven risk management for cloud computing

     Fitó Comellas, Josep Oriol; Macias Lloret, Mario; Guitart Fernández, Jordi
    International Conference on Network and Service Management
    Presentation's date: 2010-10-25
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Resource-level QoS metric for CPU-based guarantees in cloud providers

     Goiri Presa, Iñigo; Julià Massó, Ferran; Fitó Comellas, Josep Oriol; Macias Lloret, Mario; Guitart Fernández, Jordi
    International Conference on Economics of Grids, Clouds, Systems and Services
    Presentation's date: 2010-08-31
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Success of Cloud computing requires that both customers and providers can be confident that signed Service Level Agreements (SLA) are supporting their respective business activities to their best extent. Currently used SLAs fail in providing such confidence, especially when providers outsource resources to other providers. These resource providers typically support very simple metrics, or metrics that hinder an efficient exploitation of their resources. In this paper, we propose a resource-level metric for specifying finegrain guarantees on CPU performance. This metric allows resource providers to allocate dynamically their resources among the running services depending on their demand. This is accomplished by incorporating the customer’s CPU usage in the metric definition, but avoiding fake SLA violations when the customer’s task does not use all its allocated resources. As demonstrated in our evaluation, which has been conducted in a virtualized provider where we have implemented the needed infrastructure for using our metric, our solution presents fewer SLA violations than other CPU-related metrics.

  • Validación de conceptos adquiridos en una asignatura de proyecto: experiencia en ProSO

     Becerra Fontal, Yolanda; Corbalan Gonzalez, Julita; Costa Prats, Juan Jose; Gil Gómez, Maria Luisa; Guitart Fernández, Jordi
    Jornades de Docència del Departament d'Arquitectura de Computadors
    Presentation's date: 2010-02-11
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Rule-based SLA management for revenue maximisation in cloud computing markets

     Macias Lloret, Mario; Fitó Comellas, Josep Oriol; Guitart Fernández, Jordi
    International Conference on Network and Service Management
    Presentation's date: 2010-10-25
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Prediction of job resource requirements for deadline schedulers to manage high-level SLAs on the cloud

     Reig Ventura, Gemma; Alonso López, Javier; Guitart Fernández, Jordi
    IEEE International Symposium on Network Computing and Applications
    Presentation's date: 2010-07-15
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Enforcing service level agreements using an economically enhanced resource manager

     Macias Lloret, Mario; Smith, Garry; Rana, Omer; Guitart Fernández, Jordi; Torres Viñals, Jordi
    Date of publication: 2010-01
    Book chapter

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Extended resource management using client classification and economic enhancements

     Püschel, Tim; Borissov, Nikolay; Neumann, Dirk; Macias Lloret, Mario; Guitart Fernández, Jordi; Torres Viñals, Jordi
    Date of publication: 2010-01
    Book chapter

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Commercialization of computing resources will become more and more important as the transition from Grid computing in academic environments to commercial services based on concepts such as utility or Cloud computing progresses. This results in the necessity to not only base components on technical aspects, but also to include economical aspects in their design. This paper presents a framework that links technical and economical aspects to the management of computational resources. Economic enhancements like dynamic pricing and client classification are introduced based on a technical resource management environment and positioned within this resulting in a proposed architecture for an Economically Enhanced Resource Manager (EERM). The introduced approach is evaluated considering various economic design criteria and example scenarios.

  • Access to the full text
    Towards energy-aware scheduling in data centers using machine learning  Open access

     Berral Garcia, Josep Lluis; Goiri Presa, Iñigo; Nou Castell, Ramon; Julià, Ferran; Guitart Fernández, Jordi; Gavaldà Mestre, Ricard; Torres Viñals, Jordi
    1st International Conference on Energy-Efficient Computing and Networking
    Presentation's date: 2010-04-15
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    As energy-related costs have become a major economical factor for IT infrastructures and data-centers, companies and the research community are being challenged to nd better and more efficient power-aware resource management strategies. There is a growing interest in "Green" IT and there is still a big gap in this area to be covered. In order to obtain an energy-efficient data center, we propose a framework that provides an intelligent consolidation methodology using di erent techniques such as turning on/o ff machines, power-aware consolidation algorithms, and machine learning techniques to deal with uncertain information while maximizing performance. For the machine learning approach, we use models learned from previous system behaviors in order to predict power consumption levels, CPU loads, and SLA timings, and improve scheduling decisions. Our framework is vertical, because it considers from watt consumption to workload features, and cross-disciplinary, as it uses a wide variety of techniques. We evaluate these techniques with a framework that covers the whole control cycle of a real scenario, using a simulation with representative heterogeneous workloads, and we measure the quality of the results according to a set of metrics focused toward our goals, besides traditional policies. The results obtained indicate that our approach is close to the optimal placement and behaves better when the level of uncertainty increases.

    Postprint (author’s final draft)

  • Access to the full text
    Deadline constrained prediction of job resource requirements to manage high-level SLAs for SaaS cloud providers  Open access

     Reig Ventura, Gemma; Alonso López, Javier; Guitart Fernández, Jordi
    Date: 2010-04-28
    Report

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    For a non IT expert to use services in the Cloud is more natural to negotiate the QoS with the provider in terms of service-level metrics –e.g. job deadlines– instead of resourcelevel metrics –e.g. CPU MHz. However, current infrastructures only support resource-level metrics –e.g. CPU share and memory allocation– and there is not a well-known mechanism to translate from service-level metrics to resource-level metrics. Moreover, the lack of precise information regarding the requirements of the services leads to an inefficient resource allocation –usually, providers allocate whole resources to prevent SLA violations. According to this, we propose a novel mechanism to overcome this translation problem using an online prediction system which includes a fast analytical predictor and an adaptive machine learning based predictor. We also show how a deadline scheduler could use these predictions to help providers to make the most of their resources. Our evaluation shows: i) that fast algorithms are able to make predictions with an 11% and 17% of relative error for the CPU and memory respectively; ii) the potential of using accurate predictions in the scheduling compared to simple yet well-known schedulers.

  • Access to the full text
    Maximising revenue in cloud computing markets by means of economically enhanced SLA management  Open access

     Macias Lloret, Mario; Guitart Fernández, Jordi
    Date: 2010-09-01
    Report

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    This paper proposes a bidirectional communication between market brokers and resource managers in Cloud Computing Markets. This communication is implemented by means of an Economically Enhanced Resource Manager (EERM), that supports the negotiation process by deciding which tasks can be allocated or not, and under which economic and technical conditions. The EERM also uses the economic information that collects from market layers to manage the resources accordingly to concrete BLOs. This paper shows several Business Policies and Rules for maximizing the revenue of a Cloud Provider that sells its services and resources in a market. Their validity is demonstrated through several experiments that shown how the application of these rules can have a positive influence in the revenue and minimize the violations of Service-Level Agreements.

  • Introducing risk management into cloud computing

     Fitó Comellas, Josep Oriol; Guitart Fernández, Jordi
    Date: 2010-09
    Report

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Access to the full text
    SLA-driven elastic cloud hosting provider  Open access

     Fitó Comellas, Josep Oriol; Goiri Presa, Iñigo; Guitart Fernández, Jordi
    Euromicro International Conference on Parallel, Distributed, and Network-Based Processing
    Presentation's date: 2010-02-17
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    It is clear that Cloud computing is and will be a sea change for the Information Technology by changing the way in which both software and hardware are designed and purchased. In this work we address the use of this emreging computing paradigm into web hosting providers in order to avoid its resource management limitations. Thanks to the Cloud approach, resources can be provided in a dynamic way according with the needs of providers and end-users. In this paper, we present an elastic web hosting provider, namely Cloud Hosting Provider (CHP), that makes use of the outsourcing technique in order to take advantage of Cloud computing infrastructures for providing scalability and high availability capabilities to the web applications deployed on it. Furthermore, we pursue the main goal of maximizing the revenue earned by the provider through both the analysis of Service Level Agreements (SLA) and the employment of an economic model. The evaluation exposed demonstrates that the system proposed is able to properly react to the dynamic load received by the web applications and it also achieve the aforesaid revenue maximization of the provider by performing an SLA-aware resource (i.e. web servers) management.

  • Maximizing revenue in grid markets using an economically enhanced resource manager

     Macias Lloret, Mario; Rana, Omer; Smith, Garry; Guitart Fernández, Jordi; Torres Viñals, Jordi
    Concurrency and Computation: Practice and Experience
    Date of publication: 2010-09
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Traditional resource management has had as its main objective the optimization of throughput, based on parameters such as CPU, memory, and network bandwidth. With the appearance of Grid markets, new variables that determine economic expenditure, benefit and opportunity must be taken into account. The Self-organizing ICT Resource Management (SORMA) project aims at allowing resource owners and consumers to exploit market mechanisms to sell and buy resources across the Grid. SORMA’s motivation is to achieve efficient resource utilization by maximizing revenue for resource providers and minimizing the cost of resource consumption within a market environment. An overriding factor in Grid markets is the need to ensure that the desired quality of service levels meet the expectations of market participants. This paper explains the proposed use of an economically enhanced resource manager (EERM) for resource provisioning based on economic models. In particular, this paper describes techniques used by the EERM to support revenue maximization across multiple service level agreements and provides an application scenario to demonstrate its usefulness and effectiveness.

  • A survey on performance management for Internet applications

     Guitart Fernández, Jordi; Torres Viñals, Jordi; Ayguade Parra, Eduard
    Concurrency and computation. Practice and experience
    Date of publication: 2010-01-01
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Internet applications have become indispensable for many business and personal processes, turning the performance of these applications into a key issue. For this reason, recent research has comprehensively explored mechanisms for managing the performance of these applications, with special focus on dealing with overload situations and providing QoS guarantees to clients. This paper makes a survey on the different proposals in the literature for managing Internet applications' performance. We present a complete taxonomy that characterizes and classifies these proposals into several categories including request scheduling, admission control, service differentiation, dynamic resource management, service degradation, control theoretic approaches, works using queuing models, observation-based approaches that use runtime measurements, and overall approaches combining several mechanisms. For each work, we provide a brief description in order to provide the reader with a global understanding of the research progress in this area.

    Internet applications have become indispensable for many business and personal processes, turning the performance of these applications into a key issue. For this reason, recent research has comprehensively explored mechanisms for managing the performance of these applications, with special focus on dealing with overload situations and providing QoS guarantees to clients. This paper makes a survey on the different proposals in the literature for managing Internet applications’ performance. We present a complete taxonomy that characterizes and classifies these proposals into several categories including request scheduling, admission control, service differentiation, dynamic resource management, service degradation, control theoretic approaches, works using queuing models, observation-based approaches that use runtime measurements, and overall approaches combining several mechanisms. For each work, we provide a brief description in order to provide the reader with a global understanding of the research progress in this area.

  • Exploiting semantics and virtualization for SLA-driven resource allocation in service providers

     Ejarque, Jorge; de Palol, Marc; Goiri Presa, Iñigo; Julià, Ferran; Guitart Fernández, Jordi; Badia Sala, Rosa Maria; Torres Viñals, Jordi
    Concurrency and computation. Practice and experience
    Date of publication: 2010-04-01
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Resource management is a key challenge that service providers must adequately face in order to accomplish their business goals. This paper introduces a framework, the semantically enhanced resource allocator (SERA), aimed to facilitate service provider management, reducing costs and at the same time fulfilling the QoS agreed with the customers. The SERA assigns resources depending on the information given by the service providers according to its business goals and on the resource requirements of the tasks. Tasks and resources are semantically described and these descriptions are used to infer the resource assignments. Virtualization is used to provide an application specific and isolated virtual environment for each task. In addition, the system supports fine-grain dynamic resource distribution among these virtual environments based on Service-Level Agreements. The required adaptation is implemented using agents, guarantying enough resources to each task in order to meet the agreed performance goals.

  • Elastic management of tasks in virtualized environments

     Goiri Presa, Iñigo; Guitart Fernández, Jordi; Torres Viñals, Jordi
    Jornadas de Paralelismo
    Presentation's date: 2009-09-16
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Access to the full text
    Introducing virtual execution environment for application lifecycle management and SLA-driven resource distribution within service providers  Open access

     Goiri, Iñigo; Julià, Ferran; Ejarque, Jorge; de Palol, Marc; Badia Sala, Rosa Maria; Guitart Fernández, Jordi; Torres Viñals, Jordi
    IEEE International Symposium on Network Computing and Applications
    Presentation's date: 2009-07-10
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    Resource management is a key challenge that service providers must adequately face in order to ensure their profitability. This paper describes a proof-of-concept framework for facilitating resource management in service providers, which allows reducing costs and at the same time fulfilling the quality of service agreed with the customers. This is accomplished by means of virtualization. Our approach provides application-specific virtual environments and consolidates them in order to achieve a better utilization of the providers resources. In addition, it implements self-adaptive capabilities for dynamically distributing the providers resources among these virtual environments based on Service Level Agreements. The proposed solution has been implemented as a part of the Semantically-Enhanced Resource Allocator prototype developed within the BREIN European project. The evaluation shows that our prototype is able to react in very short time under changing conditions and avoid SLA violations by rescheduling efficiently the resources.

  • Addressing the use of cloud computing for web hosting providers

     Fitó Comellas, Josep Oriol; Guitart Fernández, Jordi
    Jornadas de Paralelismo
    Presentation's date: 2009-09-16
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Towards high-level SLAs with heterogeneous workloads: job resource requirements prediction for deadline schedulers

     Reig Ventura, Gemma; Alonso López, Javier; Guitart Fernández, Jordi
    Jornadas de Paralelismo
    Presentation's date: 2009-09-16
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Cloud users want to express their requirements in terms of high-level metrics (e.g. in terms of execution time, not in terms of CPU MHz). Moreover, at the submission time they would like to know if the resource provider will ful l with their requirements in order to decide if they would rather prefer another provider. On the other hand, the resource provider have to translate these high-level metrics into hard- ware related metrics, to know if he have enough resources to execute the user's requests. In this context, we present our prediction system to foresee the amount of CPU required for a job to nish before its deadline. This prediction system uses machine learning techniques to learn about the jobs and on-line adjust itself. Before all this training is done, the Prediction System uses an analytical model for this purpose. We also contribute with a deadline-based scheduler which uses these predictions to discard jobs that will not meet its deadline in order to maximize the provider's revenue by means of a dynamic and effi cient resource allocation to jobs. We show how our system is able to provide higher revenue to resource providers compared to simple yet well known schedulers like EDF, SJF, etc.

  • SLA-based resource management and allocation

     Guitart Fernández, Jordi; Macias Lloret, Mario; Rana, Omer; Wieder, Philipp; Yahyapour, Ramin; Ziegler, Wolfgang
    Date of publication: 2009-11
    Book chapter

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    The aim of the chapter is to describe how service-level agreements (SLAs) could be utilized to provide the basis for resource trading based on economic models. SLAs enable a service user to identify their requirements, and a provider to identify their capabilities. Subsequently, the terms in an SLA are necessary to ensure that mutually agreeable quality is being delivered by the provider according to the agreement. The use of service-level agreements (SLAs) in a resource management system to support Grid computing applications is described. To this end, we provide an architecture that supports the creation and management of SLAs. The architecture of the system, in terms of the components and their interactions, is first presented, followed by a description of the specific requirements for a marketoriented Grid economy. We use SLAs as a means to support reliable quality of service for Grid jobs. The creation of such an SLA requires planning and orchestration mechanisms. We will discuss these functionalities and also consider the economic aspects such as dynamic pricing and negotiation mechanisms. These mechanisms are necessary to enable SLA formation and use, and to ensure that an SLA is being adhered to during service provision.

  • A non-additive negotiation model for utility computing markets

     Macias Lloret, Mario; Guitart Fernández, Jordi
    Jornadas de Paralelismo
    Presentation's date: 2009-09-16
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window