LAYSI: A layered approach for SLA-violation propagation in self-manageable cloud infrastructures

Cloud computing represents a promising comput ing paradigm where computing resources have to be allocated to software for their execution. Self-manageable Cloud in frastructures are required to achieve that level of flexibility on one hand, and to comply to users' requirements speci fied by means of Service Level Agreements (SLAs) on the other. Such infrastructures should automatically respond to changing component, workload, and environmental conditions minimizing user interactions with the system and preventing violations of agreed SLAs. However, identification of sources responsible for the possible SLA violation and the decision about the reactive actions necessary to prevent SLA violation is far from trivial. First, in this paper we present a novel approach for mapping low-level resource metrics to SLA parameters necessary for the identification of failure sources. Second, we devise a layered Cloud architecture for the bottom-up propagation of failures to the layer, which can react to sensed SLA violation threats. Moreover, we present a communication model for the propagation of SLA violation threats to the appropriate layer of the Cloud infrastructure, which includes negotiators, brokers, and automatic service deployer. © 2010 IEEE

Modèle de confiance et ontologie probabiliste pilotés par réseaux bayésiens pour la gestion des accords de services dans l’environnement de services infonuagiques

L’infonuage est un nouveau paradigme de services informatiques disponibles à la demande qui a connu une croissance fulgurante au cours de ces dix dernières années. Le fournisseur du modèle de déploiement public des services infonuagiques décrit le service à fournir, le prix, les pénalités en cas de violation des spécifications à travers un document. Ce document s’appelle le contrat de niveau de service (SLA). La signature de ce contrat par le client et le fournisseur scelle la garantie de la qualité de service à recevoir. Ceci impose au fournisseur de gérer efficacement ses ressources afin de respecter ses engagements. Malheureusement, la violation des spécifications du SLA se révèle courante, généralement en raison de l’incertitude sur le comportement du client qui peut produire un nombre variable de requêtes vu que les ressources lui semblent illimitées. Ce comportement peut, dans un premier temps, avoir un impact direct sur la disponibilité du service. Dans un second temps, des violations à répétition risquent d'influer sur le niveau de confiance du fournisseur et sur sa réputation à respecter ses engagements. Pour faire face à ces problèmes, nous avons proposé un cadre d’applications piloté par réseau bayésien qui permet, premièrement, de classifier les fournisseurs dans un répertoire en fonction de leur niveau de confiance. Celui-ci peut être géré par une entité tierce. Un client va choisir un fournisseur dans ce répertoire avant de commencer à négocier le SLA. Deuxièmement, nous avons développé une ontologie probabiliste basée sur un réseau bayésien à entités multiples pouvant tenir compte de l’incertitude et anticiper les violations par inférence. Cette ontologie permet de faire des prédictions afin de prévenir des violations en se basant sur les données historiques comme base de connaissances. Les résultats obtenus montrent l’efficacité de l’ontologie probabiliste pour la prédiction de violation dans l’ensemble des paramètres SLA appliqués dans un environnement infonuagique.Cloud Computing is a new paradigm of IT on-demand services which has experienced tremendous growth over the past decade. The provider of Cloud computing services describes the service to be provided, its cost, and penalties for service violations within a document. This document is called Service Level Agreement (SLA). The signature of this contract by the customer and the provider guarantees the quality of service received by the customer. It also entails the provider to manage its resources efficiently to meet its commitments. Unfortunately, the SLA violation is common; it is usually caused by uncertainty about customer behavior that can make variable number of requests assuming that resources are boundless. This behavior may have an impact on the availability of the service, thus its related SLA. Repeated SLA violations will definitively have an impact on the trust level that the customer has about the provider that might no longer enjoys a good reputation in meeting its commitments. To cope with these problems, we have proposed a Framework driven by a Bayesian network that allows, first, to classify the suppliers in a Cloud directory according to their trust level. This directory can be managed by a third party entity, in which a client will choose a provider before starting SLA negotiation. Secondly, we have developed a probabilistic ontology, based on a Multi-Entity Bayesian network, which takes into account uncertainty, in the customer behavior, and makes predictions by inference; these predictions help preventing SLA violations based on historical data.. The results show the effectiveness of the probabilistic ontology for the prediction of SLA violations in a Cloud Computing environment

A framework for SLA-centric service-based Utility Computing

Nicht angegebenService oriented Utility Computing paves the way towards realization of service markets, which promise metered services through negotiable Service Level Agreements (SLA). A market does not necessarily imply a simple buyer-seller relationship, rather it is the culmination point of a complex chain of stake-holders with a hierarchical integration of value along each link in the chain. In service value chains, services corresponding to different partners are aggregated in a producer-consumer manner resulting in hierarchical structures of added value. SLAs are contracts between service providers and service consumers, which ensure the expected Quality of Service (QoS) to different stakeholders at various levels in this hierarchy. \emph{This thesis addresses the challenge of realizing SLA-centric infrastructure to enable service markets for Utility Computing.} Service Level Agreements play a pivotal role throughout the life cycle of service aggregation. The activities of service selection and service negotiation followed by the hierarchical aggregation and validation of services in service value chain, require SLA as an enabling technology. \emph{This research aims at a SLA-centric framework where the requirement-driven selection of services, flexible SLA negotiation, hierarchical SLA aggregation and validation, and related issues such as privacy, trust and security have been formalized and the prototypes of the service selection model and the validation model have been implemented. } The formal model for User-driven service selection utilizes Branch and Bound and Heuristic algorithms for its implementation. The formal model is then extended for SLA negotiation of configurable services of varying granularity in order to tweak the interests of the service consumers and service providers. %and then formalizing the requirements of an enabling infrastructure for aggregation and validation of SLAs existing at multiple levels and spanning % along the corresponding service value chains. The possibility of service aggregation opens new business opportunities in the evolving landscape of IT-based Service Economy. A SLA as a unit of business relationships helps establish innovative topologies for business networks. One example is the composition of computational services to construct services of bigger granularity thus giving room to business models based on service aggregation, Composite Service Provision and Reselling. This research introduces and formalizes the notions of SLA Choreography and hierarchical SLA aggregation in connection with the underlying service choreography to realize SLA-centric service value chains and business networks. The SLA Choreography and aggregation poses new challenges regarding its description, management, maintenance, validation, trust, privacy and security. The aggregation and validation models for SLA Choreography introduce concepts such as: SLA Views to protect the privacy of stakeholders; a hybrid trust model to foster business among unknown partners; and a PKI security mechanism coupled with rule based validation system to enable distributed queries across heterogeneous boundaries. A distributed rule based hierarchical SLA validation system is designed to demonstrate the practical significance of these notions

Automation of The SLA Life Cycle in Cloud Computing

Cloud computing has become a prominent paradigm to offer on-demand services for softwares, infrastructures and platforms. Cloud services are contracted by a service level agreement (SLA) between a cloud service provider (CSP) and a cloud service user (CSU) which contains service definitions, quality of service (QoS) parameters, guarantees and obligations. Cloud service providers mostly offer SLAs in descriptive format which is not directly consumable by a machine or a system. The SLA written in natural language may impede the utility of rapid elasticity in a cloud service. Manual management of SLAs with growing usage of cloud services can be a challenging, erroneous and tedious task especially for the CSUs acquiring multiple cloud services. The necessity of automating the complete SLA life cycle (which includes SLA description in machine readable format, negotiation, monitoring and management) becomes imminent due to complex requirements for the precise measurement of QoS parameters. Current approaches toward automating the complete SLA life cycle, lack in standardization, completeness and applicability to cloud services. Automation of different phases of the SLA life cycle (e.g. negotiation, monitoring and management) is dependent on the availability of a machine readable SLA. In this work, a structural specification for the SLAs in cloud computing (S3LACC in short) is presented which is designed specifically for cloud services, covers complete SLA life cycle and conforms with the available standards. A time efficient SLA negotiation technique is accomplished (based on the S3LACC) for concurrently negotiating with multiple CSPs. After successful negotiation process, next leading task in the SLA life cycle is to monitor the cloud services for ensuring the quality of service according to the agreed SLA. A distributed monitoring approach for the cloud SLAs is presented, in this work, which is suitable for services being used at single or multiple locations. The proposed approach reduces the number of communications of SLA violations to a monitoring coordinator by eliminating the unnecessary communications. The presented work on the complete SLA life cycle automation is evaluated and validated with the help of use cases, experiments and simulations

Autonomie, sécurité et QoS de bout en bout dans un environnement de Cloud Computing

Today, Cloud Networking is one of the recent research areas within the Cloud Computing research communities. The main challenges of Cloud Networking concern Quality of Service (QoS) and security guarantee as well as its management in conformance with a corresponding Service Level Agreement (SLA). In this thesis, we propose a framework for resource allocation according to an end-to-end SLA established between a Cloud Service User (CSU) and several Cloud Service Providers (CSPs) within a Cloud Networking environment (Inter-Cloud Broker and Federation architectures). We focus on NaaS and IaaS Cloud services. Then, we propose the self-establishing of several kinds of SLAs and the self-management of the corresponding Cloud resources in conformance with these SLAs using specific autonomic cloud managers. In addition, we extend the proposed architectures and the corresponding SLAs in order to deliver a service level taking into account security guarantee. Moreover, we allow autonomic cloud managers to expand the self-management objectives to security functions (self-protection) while studying the impact of the proposed security on QoS guarantee. Finally, our proposed architecture is validated by different simulation scenarios. We consider, within these simulations, videoconferencing and intensive computing applications in order to provide them with QoS and security guarantee in a Cloud self-management environment. The obtained results show that our contributions enable good performances for these applications. In particular, we observe that the Broker architecture is the most economical while ensuring QoS and security requirements. In addition, we observe that Cloud self-management enables violations and penalties’ reduction as well as limiting security impact on QoS guarantee.De nos jours, le Cloud Networking est considéré comme étant l'un des domaines de recherche innovants au sein de la communauté de recherche du Cloud Computing. Les principaux défis dans un environnement de Cloud Networking concernent non seulement la garantie de qualité de service (QoS) et de sécurité mais aussi sa gestion en conformité avec un accord de niveau de service (SLA) correspondant. Dans cette thèse, nous proposons un Framework pour l'allocation des ressources conformément à un SLA établi de bout en bout entre un utilisateur de services Cloud (CSU) et plusieurs fournisseurs de services Cloud (CSP) dans un environnement de Cloud Networking (architectures d’inter-Cloud Broker et Fédération). Nos travaux se concentrent sur les services Cloud de types NaaS et IaaS. Ainsi, nous proposons l'auto-établissement de plusieurs types de SLA ainsi que la gestion autonome des ressources de Cloud correspondantes en conformité avec ces SLA en utilisant des gestionnaires autonomes spécifiques de Cloud. De plus, nous étendons les architectures et les SLA proposés pour offrir un niveau de service intégrant une garantie de sécurité. Ainsi, nous permettons aux gestionnaires autonomes de Cloud d'élargir leurs objectifs de gestion autonome aux fonctions de sécurité (auto-protection) tout en étudiant l'impact de la sécurité proposée sur la garantie de QoS. Enfin, nous validons notre architecture avec différents scénarios de simulation. Nous considérons dans le cadre de ces simulations des applications de vidéoconférence et de calcul intensif afin de leur fournir une garantie de QoS et de sécurité dans un environnement de gestion autonome des ressources du Cloud. Les résultats obtenus montrent que nos contributions permettent de bonnes performances pour ce type d’applications. En particulier, nous observons que l'architecture de type Broker est la plus économique, tout en assurant les exigences de QoS et de sécurité. De plus, nous observons que la gestion autonome des ressources du Cloud permet la réduction des violations, des pénalités et limite l'impact de la sécurité sur la garantie de la QoS

Service level agreement specification for IoT application workflow activity deployment, configuration and monitoring

PhD ThesisCurrently, we see the use of the Internet of Things (IoT) within various domains such as healthcare, smart homes, smart cars, smart-x applications, and smart cities. The number of applications based on IoT and cloud computing is projected to increase rapidly over the next few years. IoT-based services must meet the guaranteed levels of quality of service (QoS) to match users’ expectations. Ensuring QoS through specifying the QoS constraints using service level agreements (SLAs) is crucial. Also because of the potentially highly complex nature of multi-layered IoT applications, lifecycle management (deployment, dynamic reconfiguration, and monitoring) needs to be automated. To achieve this it is essential to be able to specify SLAs in a machine-readable format. currently available SLA specification languages are unable to accommodate the unique characteristics (interdependency of its multi-layers) of the IoT domain. Therefore, in this research, we propose a grammar for a syntactical structure of an SLA specification for IoT. The grammar is based on a proposed conceptual model that considers the main concepts that can be used to express the requirements for most common hardware and software components of an IoT application on an end-to-end basis. We follow the Goal Question Metric (GQM) approach to evaluate the generality and expressiveness of the proposed grammar by reviewing its concepts and their predefined lists of vocabularies against two use-cases with a number of participants whose research interests are mainly related to IoT. The results of the analysis show that the proposed grammar achieved 91.70% of its generality goal and 93.43% of its expressiveness goal. To enhance the process of specifying SLA terms, We then developed a toolkit for creating SLA specifications for IoT applications. The toolkit is used to simplify the process of capturing the requirements of IoT applications. We demonstrate the effectiveness of the toolkit using a remote health monitoring service (RHMS) use-case as well as applying a user experience measure to evaluate the tool by applying a questionnaire-oriented approach. We discussed the applicability of our tool by including it as a core component of two different applications: 1) a contextaware recommender system for IoT configuration across layers; and 2) a tool for automatically translating an SLA from JSON to a smart contract, deploying it on different peer nodes that represent the contractual parties. The smart contract is able to monitor the created SLA using Blockchain technology. These two applications are utilized within our proposed SLA management framework for IoT. Furthermore, we propose a greedy heuristic algorithm to decentralize workflow activities of an IoT application across Edge and Cloud resources to enhance response time, cost, energy consumption and network usage. We evaluated the efficiency of our proposed approach using iFogSim simulator. The performance analysis shows that the proposed algorithm minimized cost, execution time, networking, and Cloud energy consumption compared to Cloud-only and edge-ward placement approaches

MSL Framework: (Minimum Service Level Framework) for Cloud Providers and Users

Cloud Computing ensures parallel computing and emerged as an efficient technology to meet the challenges of rapid growth of data that we experienced in this Internet age. Cloud computing is an emerging technology that offers subscription based services, and provide different models such as IaaS, PaaS and SaaS among other models to cater the needs of different user groups. The technology has enormous benefits but there are serious concerns and challenges related to lack of uniform standards or nonexistence of minimum benchmark for level of services offered across the industry to provide an effective, uniform and reliable service to the cloud users. As the cloud computing is gaining popularity, organizations and users are having problems to adopt the service ue to lack of minimum service level framework which can act as a benchmark in the selection of the cloud provider and provide quality of service according to the user’s expectations. The situation becomes more critical due to distributed nature of the service provider which can be offering service from any part of the world. Due to lack of minimum service level framework that will act as a benchmark to provide a uniform service across the industry there are serious concerns raised recently interms of security and data privacy breaches, authentication and authorization issues, lack of third party audit and identity management problems, integrity, confidentiality and variable data availability standards, no uniform incident response and monitoring standards, interoperability and lack of portability standards, identity management issues, lack of infrastructure protection services standards and weak governance and compliance standards are major cause of concerns for cloud users. Due to confusion and absence of universal agreed SLAs for a service model, different quality of services is being provided across the cloud industry. Currently there is no uniform performance model agreed by all stakeholders; which can provide performance criteria to measure, evaluate, and benchmark the level of services offered by various cloud providers in the industry. With the implementation of General Data Protection Regulation (GDPR) and demand from cloud users to have Green SLAs that provides better resource allocations mechanism, there will be serious implications for the cloud providers and its consumers due to lack of uniformity in SLAs and variable standards of service offered by various cloud providers. This research examines weaknesses in service level agreements offered by various cloud providers and impact due to absence of uniform agreed minimum service level framework on the adoption and usage of cloud service. The research is focused around higher education case study and proposes a conceptual model based on uniform minimum service model that acts as benchmark for the industry to ensure quality of service to the cloud users in the higher education institution and remove the barriers to the adoption of cloud technology. The proposed Minimum Service Level (MSL) framework, provides a set of minimum and uniform standards in the key concern areas raised by the participants of HE institution which are essential to the cloud users and provide a minimum quality benchmark that becomes a uniform standard across the industry. The proposed model produces a cloud computing implementation evaluation criteria which is an attempt to reduce the adoption barrier of the cloud technology and set minimum uniform standards followed by all the cloud providers regardless of their hosting location so that their performance can be measured, evaluated and compared across the industry to improve the overall QoS (Quality of Service) received by the cloud users, remove the adoption barriers and concerns of the cloud users and increase the competition across the cloud industry.A computação em nuvem proporciona a computação paralela e emergiu como uma tecnologia eficiente para enfrentar os desafios do crescimento rápido de dados que vivemos na era da Internet. A computação em nuvem é uma tecnologia emergente que oferece serviços baseados em assinatura e oferece diferentes modelos como IaaS, PaaS e SaaS, entre outros modelos para atender as necessidades de diferentes grupos de utilizadores. A tecnologia tem enormes benefícios, mas subsistem sérias preocupações e desafios relacionados com a falta de normas uniformes ou inexistência de um referencial mínimo para o nível de serviços oferecidos, na indústria, para proporcionar uma oferta eficaz, uniforme e confiável para os utilizadores da nuvem. Como a computação em nuvem está a ganhar popularidade, tanto organizações como utilizadores estão enfrentando problemas para adotar o serviço devido à falta de enquadramento de nível de serviço mínimo que possa agir como um ponto de referência na seleção de provedor da nuvem e fornecer a qualidade dos serviços de acordo com as expectativas do utilizador. A situação torna-se mais crítica, devido à natureza distribuída do prestador de serviço, que pode ser oriundo de qualquer parte do mundo. Devido à falta de enquadramento de nível de serviço mínimo que irá agir como um benchmark para fornecer um serviço uniforme em toda a indústria, existem sérias preocupações levantadas recentemente em termos de violações de segurança e privacidade de dados, autenticação e autorização, falta de questões de auditoria de terceiros e problemas de gestão de identidade, integridade, confidencialidade e disponibilidade de dados, falta de uniformidade de normas, a não resposta a incidentes e o monitoramento de padrões, a interoperabilidade e a falta de padrões de portabilidade, questões relacionadas com a gestão de identidade, falta de padrões de serviços de proteção das infraestruturas e fraca governança e conformidade de padrões constituem outras importantes causas de preocupação para os utilizadores. Devido à confusão e ausência de SLAs acordados de modo universal para um modelo de serviço, diferente qualidade de serviços está a ser fornecida através da nuvem, pela indústria da computação em nuvem. Atualmente, não há desempenho uniforme nem um modelo acordado por todas as partes interessadas; que pode fornecer critérios de desempenho para medir, avaliar e comparar o nível de serviços oferecidos por diversos fornecedores de computação em nuvem na indústria. Com a implementação do Regulamento Geral de Protecção de Dados (RGPD) e a procura da nuvem com base no impacto ambiental (Green SLAs), são acrescentadas precupações adicionais e existem sérias implicações para os forncedores de computação em nuvem e para os seus consumidores, também devido à falta de uniformidade na multiplicidade de SLAs e padrões de serviço oferecidos. A presente pesquisa examina as fraquezas em acordos de nível de serviço oferecidos por fornecedores de computação em nuvem e estuda o impacto da ausência de um quadro de nível de serviço mínimo acordado sobre a adoção e o uso no contexto da computação em nuvem. A pesquisa está orientada para a adoção destes serviços para o caso do ensino superior e as instituições de ensino superior e propõe um modelo conceptualt com base em um modelo de serviço mínimo uniforme que funciona como referência para a indústria, para garantir a qualidade do serviço para os utilizadores da nuvem numa instituição de ensino superior de forma a eliminar as barreiras para a adoção da tecnologia de computação em nuvem. O nível de serviço mínimo proposto (MSL), fornece um conjunto mínimo de normas uniformes e na áreas das principais preocupações levantadas por responsáveis de instituições de ensino superior e que são essenciais, de modo a fornecer um referencial mínimo de qualidade, que se possa tornar um padrão uniforme em toda a indústria. O modelo proposto é uma tentativa de reduzir a barreira de adoção da tecnologia de computação em nuvem e definir normas mínimas seguidas por todos os fornecedores de computação em nuvem, independentemente do seu local de hospedagem para que os seus desempenhos possam ser medidos, avaliados e comparados em toda a indústria, para melhorar a qualidade de serviço (QoS) recebida pelos utilizadores e remova as barreiras de adoção e as preocupações dos utilizadores, bem como fomentar o aumento da concorrência em toda a indústria da computação em nuvem

MSL Framework: (Minimum Service Level Framework) for cloud providers and users

Cloud Computing ensures parallel computing and emerged as an efficient technology to meet the challenges of rapid growth of data that we experienced in this Internet age. Cloud computing is an emerging technology that offers subscription based services, and provide different models such as IaaS, PaaS and SaaS among other models to cater the needs of different user groups. The technology has enormous benefits but there are serious concerns and challenges related to lack of uniform standards or nonexistence of minimum benchmark for level of services offered across the industry to provide an effective, uniform and reliable service to the cloud users. As the cloud computing is gaining popularity, organizations and users are having problems to adopt the service ue to lack of minimum service level framework which can act as a benchmark in the selection of the cloud provider and provide quality of service according to the user’s expectations. The situation becomes more critical due to distributed nature of the service provider which can be offering service from any part of the world. Due to lack of minimum service level framework that will act as a benchmark to provide a uniform service across the industry there are serious concerns raised recently interms of security and data privacy breaches, authentication and authorization issues, lack of third party audit and identity management problems, integrity, confidentiality and variable data availability standards, no uniform incident response and monitoring standards, interoperability and lack of portability standards, identity management issues, lack of infrastructure protection services standards and weak governance and compliance standards are major cause of concerns for cloud users. Due to confusion and absence of universal agreed SLAs for a service model, different quality of services is being provided across the cloud industry. Currently there is no uniform performance model agreed by all stakeholders; which can provide performance criteria to measure, evaluate, and benchmark the level of services offered by various cloud providers in the industry. With the implementation of General Data Protection Regulation (GDPR) and demand from cloud users to have Green SLAs that provides better resource allocations mechanism, there will be serious implications for the cloud providers and its consumers due to lack of uniformity in SLAs and variable standards of service offered by various cloud providers. This research examines weaknesses in service level agreements offered by various cloud providers and impact due to absence of uniform agreed minimum service level framework on the adoption and usage of cloud service. The research is focused around higher education case study and proposes a conceptual model based on uniform minimum service model that acts as benchmark for the industry to ensure quality of service to the cloud users in the higher education institution and remove the barriers to the adoption of cloud technology. The proposed Minimum Service Level (MSL) framework, provides a set of minimum and uniform standards in the key concern areas raised by the participants of HE institution which are essential to the cloud users and provide a minimum quality benchmark that becomes a uniform standard across the industry. The proposed model produces a cloud computing implementation evaluation criteria which is an attempt to reduce the adoption barrier of the cloud technology and set minimum uniform standards followed by all the cloud providers regardless of their hosting location so that their performance can be measured, evaluated and compared across the industry to improve the overall QoS (Quality of Service) received by the cloud users, remove the adoption barriers and concerns of the cloud users and increase the competition across the cloud industry.A computação em nuvem proporciona a computação paralela e emergiu como uma tecnologia eficiente para enfrentar os desafios do crescimento rápido de dados que vivemos na era da Internet. A computação em nuvem é uma tecnologia emergente que oferece serviços baseados em assinatura e oferece diferentes modelos como IaaS, PaaS e SaaS, entre outros modelos para atender as necessidades de diferentes grupos de utilizadores. A tecnologia tem enormes benefícios, mas subsistem sérias preocupações e desafios relacionados com a falta de normas uniformes ou inexistência de um referencial mínimo para o nível de serviços oferecidos, na indústria, para proporcionar uma oferta eficaz, uniforme e confiável para os utilizadores da nuvem. Como a computação em nuvem está a ganhar popularidade, tanto organizações como utilizadores estão enfrentando problemas para adotar o serviço devido à falta de enquadramento de nível de serviço mínimo que possa agir como um ponto de referência na seleção de provedor da nuvem e fornecer a qualidade dos serviços de acordo com as expectativas do utilizador. A situação torna-se mais crítica, devido à natureza distribuída do prestador de serviço, que pode ser oriundo de qualquer parte do mundo. Devido à falta de enquadramento de nível de serviço mínimo que irá agir como um benchmark para fornecer um serviço uniforme em toda a indústria, existem sérias preocupações levantadas recentemente em termos de violações de segurança e privacidade de dados, autenticação e autorização, falta de questões de auditoria de terceiros e problemas de gestão de identidade, integridade, confidencialidade e disponibilidade de dados, falta de uniformidade de normas, a não resposta a incidentes e o monitoramento de padrões, a interoperabilidade e a falta de padrões de portabilidade, questões relacionadas com a gestão de identidade, falta de padrões de serviços de proteção das infraestruturas e fraca governança e conformidade de padrões constituem outras importantes causas de preocupação para os utilizadores. Devido à confusão e ausência de SLAs acordados de modo universal para um modelo de serviço, diferente qualidade de serviços está a ser fornecida através da nuvem, pela indústria da computação em nuvem. Atualmente, não há desempenho uniforme nem um modelo acordado por todas as partes interessadas; que pode fornecer critérios de desempenho para medir, avaliar e comparar o nível de serviços oferecidos por diversos fornecedores de computação em nuvem na indústria. Com a implementação do Regulamento Geral de Protecção de Dados (RGPD) e a procura da nuvem com base no impacto ambiental (Green SLAs), são acrescentadas precupações adicionais e existem sérias implicações para os forncedores de computação em nuvem e para os seus consumidores, também devido à falta de uniformidade na multiplicidade de SLAs e padrões de serviço oferecidos. A presente pesquisa examina as fraquezas em acordos de nível de serviço oferecidos por fornecedores de computação em nuvem e estuda o impacto da ausência de um quadro de nível de serviço mínimo acordado sobre a adoção e o uso no contexto da computação em nuvem. A pesquisa está orientada para a adoção destes serviços para o caso do ensino superior e as instituições de ensino superior e propõe um modelo conceptualt com base em um modelo de serviço mínimo uniforme que funciona como referência para a indústria, para garantir a qualidade do serviço para os utilizadores da nuvem numa instituição de ensino superior de forma a eliminar as barreiras para a adoção da tecnologia de computação em nuvem. O nível de serviço mínimo proposto (MSL), fornece um conjunto mínimo de normas uniformes e na áreas das principais preocupações levantadas por responsáveis de instituições de ensino superior e que são essenciais, de modo a fornecer um referencial mínimo de qualidade, que se possa tornar um padrão uniforme em toda a indústria. O modelo proposto é uma tentativa de reduzir a barreira de adoção da tecnologia de computação em nuvem e definir normas mínimas seguidas por todos os fornecedores de computação em nuvem, independentemente do seu local de hospedagem para que os seus desempenhos possam ser medidos, avaliados e comparados em toda a indústria, para melhorar a qualidade de serviço (QoS) recebida pelos utilizadores e remova as barreiras de adoção e as preocupações dos utilizadores, bem como fomentar o aumento da concorrência em toda a indústria da computação em nuvem