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Hernández-Rodriguez, Francisco
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Publications (10 of 29) Show all publications
Papadopoulos, A. V., Klein, C., Maggio, M., Dürango, J., Dellkrantz, M., Hernández-Rodriguez, F., . . . Årzén, K.-E. (2016). Control-based load-balancing techniques: Analysis and performance evaluation via a randomized optimization approach. Control Engineering Practice, 52, 24-34
Open this publication in new window or tab >>Control-based load-balancing techniques: Analysis and performance evaluation via a randomized optimization approach
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2016 (English)In: Control Engineering Practice, ISSN 0967-0661, E-ISSN 1873-6939, Vol. 52, p. 24-34Article in journal (Refereed) Published
Abstract [en]

Cloud applications are often subject to unexpected events like flashcrowds and hardware failures. Users that expect a predictable behavior may abandon an unresponsive application when these events occur. Researchers and engineers addressed this problem on two separate fronts: first, they introduced replicas - copies of the application with the same functionality - for redundancy and scalability; second, they added a self-adaptive feature called brownout inside cloud applications to bound response times by modulating user experience. The presence of multiple replicas requires a dedicated component to direct incoming traffic: a load-balancer. Existing load-balancing strategies based on response times interfere with the response time controller developed for brownout-compliant applications. In fact, the brownout approach bounds response times using a control action. Hence, the response time, that was used to aid load-balancing decision, is not a good indicator of how well a replica is performing. To fix this issue, this paper reviews some proposal for brownout-aware load-balancing and provides a comprehensive experimental evaluation that compares them. To provide formal guarantees on the load balancing performance, we use a randomized optimization approach and apply the scenario theory. We perform an extensive set of experiments on a real machine, extending the popular lighttpd web server and load-balancer, and obtaining a production-ready implementation. Experimental results show an improvement of the user experience over Shortest Queue First (SQF)-believed to be near-optimal in the non-adaptive case. The improved user experience is obtained preserving the response time predictability.

Place, publisher, year, edition, pages
Elsevier, 2016
Keywords
Load-balancing, Randomized optimization, Cloud control
National Category
Computer Sciences
Research subject
Computer Science
Identifiers
urn:nbn:se:umu:diva-119368 (URN)10.1016/j.conengprac.2016.03.020 (DOI)000377740300003 ()
Funder
Swedish Research Council, Cloud ControlSwedish Research Council, Power and temperature control for large-scale computing infrastructuresELLIIT - The Linköping‐Lund Initiative on IT and Mobile Communications
Available from: 2016-04-18 Created: 2016-04-18 Last updated: 2018-06-07Bibliographically approved
Metsch, T., Ibidunmoye, O., Bayon-Molino, V., Butler, J., Hernández-Rodriguez, F. & Elmroth, E. (2015). Apex lake: a framework for enabling smart orchestration. In: Proceedings of the Industry Track of the 16th ACM/IFIP/USENIX Middleware Conference: . Paper presented at 16th ACM/IFIP/USENIX Middleware Conference, Middleware Industry 2015, Vancouver, Canada, 7 December 2015 through 11 December 2015 (pp. 1-7). New York, USA: Association for Computing Machinery (ACM), Article ID 1.
Open this publication in new window or tab >>Apex lake: a framework for enabling smart orchestration
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2015 (English)In: Proceedings of the Industry Track of the 16th ACM/IFIP/USENIX Middleware Conference, New York, USA: Association for Computing Machinery (ACM), 2015, p. 1-7, article id 1Conference paper, Published paper (Refereed)
Abstract [en]

The introduction of a Software-defined infrastructures brings additional challenges to the management of cloud infrastructure. With the impending convergence of telecommunications and cloud infrastructures, datacenters become an essential part of an overall integrated environment. The potential scale of such environments has significant implications as traditional orchestration approaches cannot scale appropriately. However, the combination of infrastructure topology, fine-grained operational data and advanced analytics, has the potential to deliver a scalable approach to facilitate orchestration and resource management. In this paper we introduce Apex Lake, a framework designed to address the question of "how to efficiently define and maintain a physical and logical resource and service landscape enriched by operational data, to support orchestration for optimized service delivery?" We also demonstrate with a use-case illustrating how functionalities provided by Apex Lake can be used dealing with performance anomalies.

Place, publisher, year, edition, pages
New York, USA: Association for Computing Machinery (ACM), 2015
Keywords
Cloud monitoring and orchestration, Resource Management, Datacenter Management, Software-defined Infrastructure
National Category
Computer Systems
Research subject
Computer Systems
Identifiers
urn:nbn:se:umu:diva-114696 (URN)10.1145/2830013.2830016 (DOI)2-s2.0-84981340935 (Scopus ID)978-1-4503-3727-4 (ISBN)
Conference
16th ACM/IFIP/USENIX Middleware Conference, Middleware Industry 2015, Vancouver, Canada, 7 December 2015 through 11 December 2015
Available from: 2016-01-26 Created: 2016-01-26 Last updated: 2018-06-07Bibliographically approved
Lakew, E. B., Klein, C., Hernandez-Rodriguez, F. & Elmroth, E. (2015). Performance-Based Service Differentiation in Clouds. In: 2015 15th IEEE/ACM International Symposium on Cluster, Cloud and Grid Computing (CCGrid): . Paper presented at 2015 15th IEEE ACM International Symposium on Cluster Cloud and Grid Computing (CCGrid 2015),Shenzhen, PEOPLES R CHINA,MAY 04-07, 2015 (pp. 505-514). IEEE conference proceedings
Open this publication in new window or tab >>Performance-Based Service Differentiation in Clouds
2015 (English)In: 2015 15th IEEE/ACM International Symposium on Cluster, Cloud and Grid Computing (CCGrid), IEEE conference proceedings, 2015, p. 505-514Conference paper, Published paper (Refereed)
Abstract [en]

Due to fierce competition, cloud providers need to run their data-centers efficiently. One of the issues is to increase data-center utilization while maintaining applications' performance targets. Achieving high data-center utilization while meeting applications' performance is difficult, as data-center overload may lead to poor performance of hosted services. Service differentiation has been proposed to control which services get degraded. However, current approaches are capacity-based, which are oblivious to the observed performance of each service and cannot divide the available capacity among hosted services so as to minimize overall performance degradation. In this paper we propose performance-based service differentiation. In case enough capacity is available, each service is automatically allocated the right amount of capacity that meets its target performance, expressed either as response time or throughput. In case of overload, we propose two service differentiation schemes that dynamically decide which services to degrade and to what extent. We carried out an extensive set of experiments using different services -- interactive as well as non-interactive -- by varying the workload mixes of each service over time. The results demonstrate that our solution precisely provides guaranteed performance or service differentiation depending on available capacity.

Place, publisher, year, edition, pages
IEEE conference proceedings, 2015
Keywords
cloud computing, computer centres, interactive systems, cloud providers, data centers, performance-based service differentiation, Computational modeling, Degradation, Noise, Resource management, Throughput, Time factors, Time measurement, cloud, elasticity, guaranteed service, performance models, service differentiation
National Category
Computer Systems
Identifiers
urn:nbn:se:umu:diva-108026 (URN)10.1109/CCGrid.2015.145 (DOI)000380493100051 ()978-1-4799-8006-2 (ISBN)
External cooperation:
Conference
2015 15th IEEE ACM International Symposium on Cluster Cloud and Grid Computing (CCGrid 2015),Shenzhen, PEOPLES R CHINA,MAY 04-07, 2015
Available from: 2015-09-01 Created: 2015-09-01 Last updated: 2018-06-07Bibliographically approved
Talyansky, R., Lakew, E. B., Klein, C., Hernandez-Rodriguez, F., Elmroth, E. & Levy, E. (2015). Towards Optimized Self-Management of Distributed Object Storage Systems.
Open this publication in new window or tab >>Towards Optimized Self-Management of Distributed Object Storage Systems
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2015 (English)Report (Other academic)
Abstract [en]

Cloud storage is increasingly adopted by users due to simplified storage systems compared to on-premise storage. These systems are mostly presented as Object Storage Systems (OSSs), hiding issues, such as redundancy, from users. As new industries are considering adopting clouds for storage, OSSs have to evolve to support new needs. Among the most challenging is assuring guaranteed performance.

In this paper, we present Controllable Trade-offs (CTO), an OSS-agnostic solution to add performance guarantees. CTO presents itself as a thin layer that mediates requests between the user and the OSS. For generic support, performance is controlled by tuning the rejection probability, and implemented as a user-side queue. Results show that CTO may reduce penalties 3.23 times on average and up to 68 times when the load is high.

Publisher
p. 15
Series
Report / UMINF, ISSN 0348-0542 ; 15.11
National Category
Computer Systems
Identifiers
urn:nbn:se:umu:diva-108033 (URN)
Available from: 2015-09-01 Created: 2015-09-01 Last updated: 2018-06-07Bibliographically approved
Lakew, E. B., Xu, L., Hernandez-Rodriguez, F., Elmroth, E. & Pahl, C. (2014). A synchronization mechanism for cloud accounting systems. In: 2014 International Conference on Cloud and Autonomic Computing (ICCAC 2014): . Paper presented at 2014 IEEE International Conference on Cloud and Autonomic Computing (ICCAC), Imperial College, London, ENGLAND, SEP 08-12, 2014 (pp. 111-120).
Open this publication in new window or tab >>A synchronization mechanism for cloud accounting systems
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2014 (English)In: 2014 International Conference on Cloud and Autonomic Computing (ICCAC 2014), 2014, p. 111-120Conference paper, Published paper (Refereed)
Abstract [en]

In current cloud systems, services run across multiple geographically distributed clusters and continuously generate resource usage data due to constant resource consumption. In the context of accounting, resource usage data generated from each cluster during service runtime must be collected and aggregated into a single cloud-wide record so that a single bill can be created. This paper presents a mechanism to synchronize accounting records among distributed accounting system peers. Run time resource usage generated from different clusters is synchronized to maintain a single cloud-wide view of the data so that a single bill can be created. We provide a set of accounting system requirements and an evaluation which verifies that the solution fulfills these requirements. Experimental results show that our solution produces less overhead in terms of data exchange and scales near-linearly with the size of clusters with no single point of failure.

Keywords
Distributed Accounting, Postpaid, Cloud, Synchronization
National Category
Computer and Information Sciences
Identifiers
urn:nbn:se:umu:diva-87753 (URN)10.1109/ICCAC.2014.11 (DOI)000370731000016 ()978-1-4799-5841-2 (ISBN)
Conference
2014 IEEE International Conference on Cloud and Autonomic Computing (ICCAC), Imperial College, London, ENGLAND, SEP 08-12, 2014
Available from: 2014-04-08 Created: 2014-04-08 Last updated: 2018-06-08Bibliographically approved
Lakew, E. B., Lei, X., Francisco, H.-R., Erik, E. & Claus, P. (2014). A Tree-based Protocol for Enforcing Quotas in Clouds. In: the IEEE 10th 2014 World Congress on Services (SERVICES 2014): . Paper presented at the IEEE 10th 2014 World Congress on Services (SERVICES 2014). IEEE Computer Society
Open this publication in new window or tab >>A Tree-based Protocol for Enforcing Quotas in Clouds
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2014 (English)In: the IEEE 10th 2014 World Congress on Services (SERVICES 2014), IEEE Computer Society, 2014Conference paper, Published paper (Refereed)
Abstract [en]

Services are more and more hosted on cloud nodes for enhancing their performance and increasing their availability. The virtually unlimited availability of resources enables service owners to consume resources without quantitative restrictions, paying only for what they consume. To avoid cost overrun, resource consumption must be controlled and capped when necessary.We present a distributed tree-based protocol to manage quotas in clouds that minimizes communication overhead and reduces the time required to inspect if a quota has been exhausted. Experimental evaluation shows that our protocol provides 42% more communication savings and is up to 15 times faster compared to a distributed baseline solution.

Place, publisher, year, edition, pages
IEEE Computer Society, 2014
Keywords
Distributed Quota Monitoring, Distributed Quota Enforcement and Management, Distributed Credit Management, Clouds
National Category
Computer Systems
Identifiers
urn:nbn:se:umu:diva-93382 (URN)
Conference
the IEEE 10th 2014 World Congress on Services (SERVICES 2014)
Available from: 2014-09-18 Created: 2014-09-18 Last updated: 2018-06-07Bibliographically approved
Sedaghat, M., Hernández-Rodriguez, F. & Elmroth, E. (2014). Autonomic resource allocation for cloud data centers: a peer to peer approach. In: 2014 International Conference on Cloud and Autonomic Computing (ICCAC 2014): . Paper presented at International Conference on Cloud and Autonomic Computing (ICCAC), SEP 08-12, 2014, Imperial Coll, London, ENGLAND (pp. 131-140). IEEE Computer Society
Open this publication in new window or tab >>Autonomic resource allocation for cloud data centers: a peer to peer approach
2014 (English)In: 2014 International Conference on Cloud and Autonomic Computing (ICCAC 2014), IEEE Computer Society, 2014, , p. 10p. 131-140Conference paper, Published paper (Refereed)
Abstract [en]

We address the problem of resource management for large scale cloud data centers. We propose a Peer to Peer (P2P) resource management framework, comprised of a number of agents, overlayed as a scale-free network. The structural properties of the overlay, along with dividing the management responsibilities among the agents enables the management framework to be scalable in terms of both the number of physical servers and incoming Virtual Machine (VM) requests, while it is computationally feasible. While our framework is intended for use in different cloud management functionalities, e.g. admission control or fault tolerance, we focus on the problem of resource allocation in clouds. We evaluate our approach by simulating a data center with 2500 servers, striving to allocate resources to 20000 incoming VM placement requests. The simulation results indicate that by maintaining an efficient request propagation, we can achieve promising levels of performance and scalability when dealing with large number of servers and placement requests.

Place, publisher, year, edition, pages
IEEE Computer Society, 2014. p. 10
Keywords
cloud computing, peer to peer, resource management
National Category
Engineering and Technology
Research subject
Computer Science
Identifiers
urn:nbn:se:umu:diva-93273 (URN)10.1109/ICCAC.2014.16 (DOI)000370731000018 ()978-1-4799-5841-2 (ISBN)
Conference
International Conference on Cloud and Autonomic Computing (ICCAC), SEP 08-12, 2014, Imperial Coll, London, ENGLAND
Available from: 2014-09-15 Created: 2014-09-15 Last updated: 2018-06-07Bibliographically approved
Klein, C., Maggio, M., Årzén, K.-E. & Hernández-Rodriguez, F. (2014). Brownout: Building More Robust Cloud Applications. In: 36th International Conference on Software Engineering (ICSE 2014): . Paper presented at 36th International Conference on Software Engineering ICSE 2014, Hyderabad, India, May 31-June 7 2014 (pp. 700-711). ACM Digital Library
Open this publication in new window or tab >>Brownout: Building More Robust Cloud Applications
2014 (English)In: 36th International Conference on Software Engineering (ICSE 2014), ACM Digital Library, 2014, p. 700-711Conference paper, Published paper (Refereed)
Abstract [en]

Self-adaptation is a first class concern for cloud applications, which should be able to withstand diverse runtime changes. Variations are simultaneously happening both at the cloud infrastructure level - for example hardware failures - and at the user workload level - flash crowds. However, robustly withstanding extreme variability, requires costly hardware over-provisioning. In this paper, we introduce a self-adaptation programming paradigm called brownout. Using this paradigm, applications can be designed to robustly withstand unpredictable runtime variations, without over-provisioning. The paradigm is based on optional code that can be dynamically deactivated through decisions based on control theory. We modified two popular web application prototypes - RUBiS and RUBBoS - with less than 170 lines of code, to make them brownout-compliant. Experiments show that brownout self-adaptation dramatically improves the ability to withstand flash-crowds and hardware failures.

Place, publisher, year, edition, pages
ACM Digital Library, 2014
Keywords
adaptive Software, control theory, brownout, cloud
National Category
Computer Systems Control Engineering
Research subject
Automatic Control; Computer Science
Identifiers
urn:nbn:se:umu:diva-84212 (URN)10.1145/2568225.2568227 (DOI)000387829200062 ()
Conference
36th International Conference on Software Engineering ICSE 2014, Hyderabad, India, May 31-June 7 2014
Projects
Cloud Control
Funder
eSSENCE - An eScience CollaborationEU, FP7, Seventh Framework Programme, 257019Linnaeus research environment CADICSELLIIT - The Linköping‐Lund Initiative on IT and Mobile CommunicationsSwedish Research Council, C0590801
Note

accepted

Available from: 2013-12-18 Created: 2013-12-18 Last updated: 2019-06-19Bibliographically approved
Sedaghat, M., Hernández-Rodriguez, F., Elmroth, E. & Girdzijauskas, Š. (2014). Divide the task, multiply the outcome: cooperative VM consolidation. In: Proceedings of The 6th IEEE International Conference on Cloud Computing Technology and Science (CloudCom 2014): . Paper presented at The 6th IEEE International Conference on Cloud Computing Technology and Science (CloudCom 2014), 15-18 Dec. 2014 Singapore (pp. 300-305). IEEE
Open this publication in new window or tab >>Divide the task, multiply the outcome: cooperative VM consolidation
2014 (English)In: Proceedings of The 6th IEEE International Conference on Cloud Computing Technology and Science (CloudCom 2014), IEEE, 2014, , p. 6p. 300-305Conference paper, Published paper (Refereed)
Abstract [en]

Efficient resource utilization is one of the mainconcerns of cloud providers, as it has a direct impact onenergy costs and thus their revenue. Virtual machine (VM)consolidation is one the common techniques, used by infrastruc-ture providers to efficiently utilize their resources. However,when it comes to large-scale infrastructures, consolidationdecisions become computationally complex, since VMs aremulti-dimensional entities with changing demand and unknownlifetime, and users often overestimate their actual demand.These uncertainties urges the system to take consolidationdecisions continuously in a real time manner.In this work, we investigate a decentralized approach forVM consolidation using Peer to Peer (P2P) principles. Weinvestigate the opportunities offered by P2P systems, as scalableand robust management structures, to address VM consol-idation concerns. We present a P2P consolidation protocol,considering the dimensionality of resources and dynamicityof the environment. The protocol benefits from concurrencyand decentralization of control and it uses a dimension awaredecision function for efficient consolidation. We evaluate theprotocol through simulation of 100,000 physical machinesand 200,000 VM requests. Results demonstrate the potentialsand advantages of using a P2P structure to make resourcemanagement decisions in large scale data centers. They showthat the P2P approach is feasible and scalable and producesresource utilization of 75% when the consolidation aim is 90%.

Place, publisher, year, edition, pages
IEEE, 2014. p. 6
Series
International Conference on Cloud Computing Technology and Science, ISSN 2330-2194
Keywords
Cloud computing, Peer to Peer, Gossip protocols, VM consolidation, Resource management
National Category
Engineering and Technology
Research subject
Computing Science
Identifiers
urn:nbn:se:umu:diva-98898 (URN)10.1109/CloudCom.2014.81 (DOI)000392947000041 ()978-1-4799-4093-6 (ISBN)
Conference
The 6th IEEE International Conference on Cloud Computing Technology and Science (CloudCom 2014), 15-18 Dec. 2014 Singapore
Available from: 2015-01-28 Created: 2015-01-28 Last updated: 2018-06-07Bibliographically approved
Klein, C., Papadopoulos, A. V., Dellkrantz, M., Dürango, J., Maggio, M., Årzén, K.-E., . . . Elmroth, E. (2014). Improving Cloud Service Resilience using Brownout-Aware Load-Balancing. In: 2014 IEEE 33RD INTERNATIONAL SYMPOSIUM ON RELIABLE DISTRIBUTED SYSTEMS (SRDS): . Paper presented at 2014 IEEE 33RD INTERNATIONAL SYMPOSIUM ON RELIABLE DISTRIBUTED SYSTEMS (SRDS), OCT 06-09, 2014, Nara, JAPAN (pp. 31-40). IEEE Computer Society
Open this publication in new window or tab >>Improving Cloud Service Resilience using Brownout-Aware Load-Balancing
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2014 (English)In: 2014 IEEE 33RD INTERNATIONAL SYMPOSIUM ON RELIABLE DISTRIBUTED SYSTEMS (SRDS), IEEE Computer Society, 2014, p. 31-40Conference paper, Published paper (Refereed)
Abstract [en]

We focus on improving resilience of cloud services (e.g., e-commerce website), when correlated or cascading failures lead to computing capacity shortage. We study how to extend the classical cloud service architecture composed of a load-balancer and replicas with a recently proposed self-adaptive paradigm called brownout. Such services are able to reduce their capacity requirements by degrading user experience (e.g., disabling recommendations).

Combining resilience with the brownout paradigm is to date an open practical problem. The issue is to ensure that replica self-adaptivity would not confuse the load-balancing algorithm, overloading replicas that are already struggling with capacity shortage. For example, load-balancing strategies based on response times are not able to decide which replicas should be selected, since the response times are already controlled by the brownout paradigm.

In this paper we propose two novel brownout-aware load-balancing algorithms. To test their practical applicability, we extended the popular lighttpd web server and load-balancer, thus obtaining a production-ready implementation. Experimental evaluation shows that the approach enables cloud services to remain responsive despite cascading failures. Moreover, when compared to Shortest Queue First (SQF), believed to be near-optimal in the non-adaptive case, our algorithms improve user experience by 5%, with high statistical significance, while preserving response time predictability.

Place, publisher, year, edition, pages
IEEE Computer Society, 2014
Series
Symposium on Reliable Distributed Systems Proceedings, ISSN 1060-9857
Keywords
cloud, load-balancing, self-adaptation, control theory, statistical evaluation
National Category
Computer Systems Control Engineering
Research subject
Computer Science
Identifiers
urn:nbn:se:umu:diva-91327 (URN)000380439400004 ()978-1-4799-5584-8 (ISBN)
Conference
2014 IEEE 33RD INTERNATIONAL SYMPOSIUM ON RELIABLE DISTRIBUTED SYSTEMS (SRDS), OCT 06-09, 2014, Nara, JAPAN
Projects
Cloud Control
Funder
Swedish Research CouncilELLIIT - The Linköping‐Lund Initiative on IT and Mobile CommunicationsLinnaeus research environment CADICS
Available from: 2014-07-29 Created: 2014-07-29 Last updated: 2018-06-07Bibliographically approved
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