SLA-driven dynamic cloud resource management

As the size and complexity of Cloud systems increase, the manual management of these solutions becomes a challenging issue as more personnel, resources and expertise are needed. Service Level Agreement (SLA)- aware autonomic cloud solutions enable managing large scale infrastructure management meanwhile supporting multiple dynamic requirement from users. This paper contributes to these topics by the introduction of Cloudcompaas, a SLA-aware PaaS Cloud platform that manages the complete resource lifecycle. This platform features an extension of the SLA specification WS-Agreement, tailored to the specific needs of Cloud Computing. In particular, Cloudcompaas enables Cloud providers with a generic SLA model to deal with higher-level metrics, closer to end-user perception, and with flexible composition of the requirements of multiple actors in the computational scene. Moreover, Cloudcompaas provides a framework for general Cloud computing applications that could be dynamically adapted to correct the QoS violations by using the elasticity features of Cloud infrastructures. The effectiveness of this solution is demonstrated in this paper through a simulation that considers several realistic workload profiles, where Cloudcompaas achieves minimum cost and maximum efficiency, under highly heterogeneous utilization patterns. © 2013 Elsevier B.V. All rights reserved.This work has been developed under the support of the program Formacion de Personal Investigador de Caracter Predoctoral grant number BFPI/2009/103, from the Conselleria d'Educacio of the Generalitat Valenciana. Also, the authors wish to thank the financial support received from The Spanish Ministry of Education and Science to develop the project 'CodeCloud', with reference TIN2010-17804.García García, A.; Blanquer Espert, I.; Hernández García, V. (2014). SLA-driven dynamic cloud resource management. Future Generation Computer Systems. 31:1-11. https://doi.org/10.1016/j.future.2013.10.005S1113

Cloud Platform-as-a-Service

O Cloud Computing tem emergido como sendo um novo paradigma para entrega de serviços através da Internet. Neste mercado em expansão, o serviço de PaaS (Platform-as-a-Service) tem sido objeto de grande interesse por parte das mais variadas organizações permitindo o fácil deployment de aplicações sem necessidade de uma infra-estrutura dedicada, instalação de dependências ou configuração de servidores. No entanto, cada fornecedor de soluções PaaS acaba por gerar um lock-in do utiliza- dor às suas características proprietárias, tecnologias ou APIs (Application Programming Interfaces). Além disso, dando como garantida a conectividade até aos clientes, a rede de operadores como seja o caso da PT (Portugal Telecom) acaba por servir apenas de dumb-pipe entre o fornecedor e os seus clientes

An intelligent, time-optimized monitoring scheme for edge nodes

Monitoring activities over edge resources and services are essential in today's applications. Edge nodes can monitor their status and end users/applications requirements to identify their ‘matching’ and deliver alerts when violations are present. Violations are related to any disturbance of the desired Quality of Service (QoS). QoS depends on a number of performance metrics and can differ among applications. In this paper, we propose the use of an intelligent mechanism to be incorporated in monitoring tools adopted by edge nodes. The proposed mechanism observes the realizations of performance parameters that result in specific QoS values and decides when it is the right time to ‘fire’ mitigation actions. Hence, edge nodes are capable of changing their configuration to secure the desired QoS levels as dictated by end users/applications requirements. In our work, a mitigation action could involve either upgrades in the current services/resources or offloading tasks by transferring computational load and data to peer nodes or the Cloud. We present our model and provide formulations for the solution of the problem. A high number of simulations reveal the performance of the proposed mechanism. Our experiments show that our scheme outperforms any deterministic model defined for the discussed setting as well as other efforts found in the relevant literature

Cloud computing: survey on energy efficiency

International audienceCloud computing is today’s most emphasized Information and Communications Technology (ICT) paradigm that is directly or indirectly used by almost every online user. However, such great significance comes with the support of a great infrastructure that includes large data centers comprising thousands of server units and other supporting equipment. Their share in power consumption generates between 1.1% and 1.5% of the total electricity use worldwide and is projected to rise even more. Such alarming numbers demand rethinking the energy efficiency of such infrastructures. However, before making any changes to infrastructure, an analysis of the current status is required. In this article, we perform a comprehensive analysis of an infrastructure supporting the cloud computing paradigm with regards to energy efficiency. First, we define a systematic approach for analyzing the energy efficiency of most important data center domains, including server and network equipment, as well as cloud management systems and appliances consisting of a software utilized by end users. Second, we utilize this approach for analyzing available scientific and industrial literature on state-of-the-art practices in data centers and their equipment. Finally, we extract existing challenges and highlight future research directions

Developing a user-centric distributed middleware for SLA monitoring in SaaS cloud computing using RESTful services

One of the most important discussions in the cloud computing field is user satisfaction with the associated services. It is important to maintain trusted relationships between clients and providers, for customers who pay subscriptions to receive these services in a timely and accurate manner. Despite the overwhelming advantages of cloud services, clients sometimes have problems in service outage and resource failure. This is due to the failures that can happen in cloud servers, which cause outages to the received services. For example, the failure of Microsoft Office 365 on 18th of January 2016, caused email disruption which lasted for many days. New measures are needed to ensure that the contract signed between the two parties, known as a Service Level Agreement (SLA) has been adhered to. Measuring the quality of cloud computing provision from the client’s point of view is, therefore, essential in order to ensure that the service conforms to the level specified in the agreement; this is usually referred to as Quality of Experience. In recent years, there has been an increase shift in using Simple Object Access Protocol (SOAP) to Representational State Transfer (REST) technology as an alternative technology in cloud applications APIs development. However, there is a penchant in most of cloud monitoring solutions to use SOAP protocol in managing the monitoring process. This trend has drawn the attention to the need for using REST technology in transferring the monitored data between the provider side and the client side. This thesis addresses the problem of monitoring the quality of Software as a Service from the users’ perspective, and the need for developing a lightweight middleware for delivering the monitored data in Software as a Service cloud computing. The aim of this research is to propose a user centric approach for monitoring Software as a Service in cloud computing, and to reduce the overhead caused by the monitoring process. In order to achieve this aim, a user centric middleware capable of monitoring the Quality of Experience has been developed. The developed middleware is a Service Oriented middleware which uses RESTful web services and provides the monitoring process as an add-on service. A new approach was developed for embedding the SLA parameters in REST services through extending the HTTP messages and exploiting the HEAD and OPTIONS methods to transmit the monitored data and to send notifications about anySLA violations. This reduces the need to exchange extra monitoring messages between the two parties, and hence reduces the communication overhead. Furthermore, the estimation of the user satisfaction was implemented by developing a decision making approach to estimate the Quality of Experience value and to predict the effect of the SLA parameters and the Quality of Service (QoS) on the user satisfaction. Fuzzy logic techniques were employed in the decision making process.The developed middleware is called MonSLAR, for Monitoring SLA for Restful services in SaaS cloud computing environments. The middleware was implemented using the Java programming language, and tested successfully in a cloud environment to prove the proposed solution’s capability of transmitting the data using the REST methods, in addition to providing automated and real time feedback. MonSLAR uses a distributed monitoring architecture, which allows SLA parameters to be embedded in the requests and responses of the REST protocol. The proposed middleware was evaluated by measuring the overhead caused by using REST technology in terms of response time and message size and compared to existing techniques. The results revealed that the message size overhead of using REST is approximately five times less than the message size overhead caused by SOAP. Furthermore, the response time overhead of the monitoring process is comparable to the overhead caused by the available monitoring frameworks. To sum up, the proposed middleware will help to strengthen the relationship between the client and the provider by using real time notifications to the client about any degradation in the cloud services, using a lightweight middleware

SLA-Driven Cloud Computing Domain Representation and Management

The assurance of Quality of Service (QoS) to the applications, although identified as a key feature since long ago [1], is one of the fundamental challenges that remain unsolved. In the Cloud Computing context, Quality of Service is defined as the measure of the compliance of certain user requirement in the delivery of a cloud resource, such as CPU or memory load for a virtual machine, or more abstract and higher level concepts such as response time or availability. Several research groups, both from academia and industry, have started working on describing the QoS levels that define the conditions under which the service need to be delivered, as well as on developing the necessary means to effectively manage and evaluate the state of these conditions. [2] propose Service Level Agreements (SLAs) as the vehicle for the definition of QoS guarantees, and the provision and management of resources. A Service Level Agreement (SLA) is a formal contract between providers and consumers, which defines the quality of service, the obligations and the guarantees in the delivery of a specific good. In the context of Cloud computing, SLAs are considered to be machine readable documents, which are automatically managed by the provider's platform. SLAs need to be dynamically adapted to the variable conditions of resources and applications. In a multilayer architecture, different parts of an SLA may refer to different resources. SLAs may therefore express complex relationship between entities in a changing environment, and be applied to resource selection to implement intelligent scheduling algorithms. Therefore SLAs are widely regarded as a key feature for the future development of Cloud platforms. However, the application of SLAs for Grid and Cloud systems has many open research lines. One of these challenges, the modeling of the landscape, lies at the core of the objectives of the Ph. D. Thesis.García García, A. (2014). SLA-Driven Cloud Computing Domain Representation and Management [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/36579TESI

Monitoring self-adaptive applications within edge computing frameworks: A state-of-the-art review

Recently, a promising trend has evolved from previous centralized computation to decentralized edge computing in the proximity of end-users to provide cloud applications. To ensure the Quality of Service (QoS) of such applications and Quality of Experience (QoE) for the end-users, it is necessary to employ a comprehensive monitoring approach. Requirement analysis is a key software engineering task in the whole lifecycle of applications; however, the requirements for monitoring systems within edge computing scenarios are not yet fully established. The goal of the present survey study is therefore threefold: to identify the main challenges in the field of monitoring edge computing applications that are as yet not fully solved; to present a new taxonomy of monitoring requirements for adaptive applications orchestrated upon edge computing frameworks; and to discuss and compare the use of widely-used cloud monitoring technologies to assure the performance of these applications. Our analysis shows that none of existing widely-used cloud monitoring tools yet provides an integrated monitoring solution within edge computing frameworks. Moreover, some monitoring requirements have not been thoroughly met by any of them

Uma abordagem estratificada à monitorização de serviços Cloud

Dissertação de mestrado em Redes e Serviços de ComunicaçõesA monitorização é uma tarefa essencial na gestão e engenharia das redes de comunicações atuais. Face a paradigmas como Cloud Computing e Cloud Services, os desafios colocados à monitorização de redes e serviços são ainda mais variados e exigentes. Cloud Computing inclui modelos de serviços distintos (IaaS, PaaS, SaaS), compartilhando algumas necessidades comuns na medição de infraestruturas, mas com especificidades de acordo com o tipo de serviço prestado e recursos envolvidos. A complexidade associada à monitorização destes ambientes e a falta de normas até agora, exige uma análise cuidadosa e sistematizada, de modo a obter uma melhor compreensão acerca dos pontos-chave envolvidos na avaliação dos serviços prestados. Neste contexto, esta dissertação apresenta uma abordagem estratificada à monitorização de Serviços Cloud. O objetivo principal prende-se com a identificação das várias dimensões da monitorização de serviços Cloud, combinando as perspetivas do fornecedor de infraestruturas e de serviços, e dos clientes. Consequentemente, a monitorização do estado dos recursos, da qualidade de serviço, qualidade de experiência e contratos de serviço são aspetos a cobrir. Este processo envolve a identificação de parâmetros e métricas relevantes para cada dimensão monitorizada. Através de uma visão estratificada do problema, este estudo contribui para alcançar uma abordagem mais clara e eficiente à monitorização de serviços Cloud.Monitoring is an essential task in the management and engineering of today’s communication networks. To face paradigms such as cloud computing and cloud services, the challenges of monitoring networks and services are even more varied and demanding. Cloud Computing includes distinct service models (IaaS, PaaS, SaaS), sharing common needs in measuring the infrastructure, but with specificities according to the type of service and resources involved. The complexity of monitoring these environments and the lack of standards so far urge for a careful analysis, systematizing and understanding the key points involved when assessing the services provided. In this context, this dissertation presents a layered approach to Cloud Services monitoring. The main objective concerns the identification of the multiple dimensions of monitoring cloud services, combining the perspectives of providers and customers. Consequently, the monitoring of resources, quality of service, quality of experience and service contracts are aspects to cover. This process involves the identification of relevant parameters and metrics for each monitoring dimension. Taking a stratified view of the problem, this study contributes to achieve a clearer and more efficient approach to cloud services monitoring

Interoperabilidade e portabilidade em ambientes PaaS

Dissertação de mestrado em Redes e Serviços de ComunicaçõesO Cloud Computing tem emergido como sendo um novo paradigma para entrega de serviçoes através da Internet. Neste mercado em expansão, o serviço de PaaS (Platform-as-a-Service) tem sido objeto de grande interesse por parte das mais variadas organizações permitindo o fácil deployment de aplicações sem necessidade de uma infraestrutura dedicada, instalação de dependências ou configuração de servidores. No entanto, cada fornecedor de solução PaaS acaba por gerar um lock-in do utilizador às suas características proprietárias, tecnologias ou APIs (Application Programming Interfaces). Além disso, dando como garantida a conectividade até aos clientes, a rede de operadores como seja o caso da Portugal Telecom (PT) acaba por servir apenas de dumb-pipe entre o fornecedor e os seus clientes. Este projeto foca-se na especificação, desenvolvimento e avaliação de uma camada de abstração que visa unificar os processos de gestão e aquisição de informação sobre aplicações e bases de dados criadas atraves de diversos PaaS, de modo a combater o lock-in existente no mercado. Neste sentido, um utilizador de PaaS pode selecionar a plataforma mais adequada para uma aplicação interagindo de forma idêntica com qualquer fornecedor suportado,tendo também a possibilidade de migrar aplicações entre fornecedores distintos. Assim sendo, um operador como a PT tem agora a possibilidade de agir como um mediador entre os utilizadores e os fornecedores de PaaS