Conceptual Service Level Agreement Mechanism to Minimize the SLA Violation with SLA Negotiation Process in Cloud Computing Environment

تُستخدم الخدمة عبر الإنترنت لتكون بمثابة الدفع لكل استخدام في الحوسبة السحابية. لا يحتاج مستخدم الخدمة إلى عقد طويل مع مزودي الخدمات السحابية. اتفاقية مستوى الخدمة (SLAs) هي تفاهمات تم تحديدها بين مزودي الخدمة السحابية وغيرهم ، على سبيل المثال ، مستخدم الخدمة أو المشغل الوسيط أو المشغلين المراقبين. نظرًا لأن الحوسبة السحابية هي تقنية مستمرة تقدم العديد من الخدمات لتطبيقات الأعمال الأساسية وأنظمة قابلة للتكيف لإدارة الاتفاقيات عبر الإنترنت تعتبر مهمة تحافظ على اتفاقية مستوى الخدمةو جودة الخدمة لمستخدم السحابة. إذا فشل مزود الخدمة في الحفاظ على الخدمة المطلوبة ، فإن اتفاقية مستوى الخدمة تعتبر انتهاكًا لاتفاقية مستوى الخدمة. الهدف الرئيسي هو تقليل انتهاكات اتفاقية مستوى الخدمة (SLA) للحفاظ على جودة الخدمة لمستخدمي السحابة. في هذه المقالة البحثية ، اقترحنا صندوق أدوات للمساعدة في إجراء تبادل اتفاقية مستوى الخدمة مع مزودي الخدمة والذي سيمكن العميل السحابي من الإشارة إلى متطلبات جودة الخدمة واقترح خوارزمية بالإضافة إلى نموذج التفاوض من اجل التفاوض على الطلب مع الخدمة لمقدمي الخدمة لإنتاج اتفاقية أفضل بين مقدم الخدمة ومستهلك الخدمة السحابية. وبالتالي ، يمكن للإطار الذي تمت مناقشته تقليل انتهاكات اتفاقية مستوى الخدمة وكذلك خيبات الأمل في المفاوضات وتوسيع نطاق كفاية التكلفة. علاوة على ذلك ، فإن مجموعة أدوات اتفاقية مستوى الخدمة المقترحة منتجة بشكل إضافي للعملاء حتى يتمكن العملاء من تأمين سداد قيمة معقولة مقابل تقليل جودة الخدمة أو وقت التنازل. يوضح هذا البحث أنه يمكن الحفاظ على مستوى الضمان في موفري الخدمات السحابية من خلال نقل الخدمات دون انقطاع من منظور العميل.Online service is used to be as Pay-Per-Use in Cloud computing. Service user need not be in a long time contract with cloud service providers. Service level agreements (SLAs) are understandings marked between a cloud service providers and others, for example, a service user, intermediary operator, or observing operators. Since cloud computing is an ongoing technology giving numerous services to basic business applications and adaptable systems to manage online agreements are significant. SLA maintains the quality-of-service to the cloud user. If service provider fails to maintain the required service SLA is considered to be SLA violated. The main aim is to minimize the SLA violations for maintain the QoS of their cloud users. In this research article, a toolbox is proposed to help the procedure of exchanging of a SLA with the service providers that will enable the cloud client in indicating service quality demands and an algorithm as well as Negotiation model is also proposed to negotiate the request with the service providers to produce a better agreement between service provider and cloud service consumer. Subsequently, the discussed framework can reduce SLA violations as well as negotiation disappointments and have expanded cost-adequacy. Moreover, the suggested SLA toolkit is additionally productive to clients so clients can secure a sensible value repayment for diminished QoS or conceding time. This research shows the assurance level in the cloud service providers can be kept up by as yet conveying the services with no interruption from the client's perspectiv

Kostnadsanalys av en molnbaserad konvergerad IT arkitektur för ett litet företag

The purpose of this thesis is to study the dispersed IT architecture of a small sized enterprise versus a converged cloud based IT architecture. Cloud computing enables moving to a pay-as-you-go model with low up-front investment making it attractive to small sized enterprises. Other traits that appeal to small sized enterprises are flexibility, modularity and ease of use. However, an important factor to be aware of when investing in a cloud solution is hidden costs, such as extra fees and premium support costs. The two scenarios (dispersed versus converged) are studied in terms of Total Cost of Ownership (TCO) and Customer-Provider Strategic Alignment Maturity (CPSAM) as the IT services are outsourced in both scenarios. The TCO provides cost information on both scenarios indicating where savings could be made and exposes excess expenditures. Whilst the CPSAM studies the outsourcing strategies and unveils vendor management issues. Based on the analysis the main differences in TCO related to operational costs, which includes maintenance and support costs. These can vary, however taking in consideration a margin of error there was still a clear difference between the two scenarios and the converged architecture showed a decrease in operational costs. The CPSAM analysis showed issues in communication, articulation of processes and lacking knowledge of the whole value network. Some of the risks could be minimized by choosing scenario 2 as vendor management would be centralized and less complex. However, many of the recommended actions concern both scenarios, such as formalizing a collaboration blueprint, re-assessing contracts for suitability, defining and communicating roles and responsibilities and defining and articulating communication practices.Syftet med detta diplomarbete är att undersöka ett litet företags icke-centrerade IT arkitektur i jämförelse med en centrerad molnbaserad IT arkitektur. Molntjänster är attraktiva för små företag eftersom startavgiften för investeringen är låg och kostnadsmodellen ändras till så kallad ”pay-as-you-go” modell där man endast betalar för de tjänster som används. Andra egenskaper som mindre företag uppskattar är flexibilitet, modularitet och användarvänlighet. Dock är det viktigt att ta i beaktande så kallade gömda kostnader som till exempel kan bestå av extra utgifter eller premium support kostnader. Studien undersöker de två scenarierna (dispergerad och konvergerad) både ur ett Total ägandekostnads perspektiv (TCO) och ur ett maturitets perspektiv (CPSAM) där kundens och leverantörens strategiska positionering analyseras. Analysen på Total ägandekostnader ger kostnadsinformation för båda scenarierna och utgående från den information kan man identifiera besparingsmöjligheter och eventuella överskott i utgifter. CPSAM analysen studerar outsourcing strategier och avslöjar problem i leverantörhanteringen. Utgående från Total ägandekostnads analysen härstammar de största kostnadsskillnaderna från operativa kostnader så som underhåll och support. Dessa kostnader kan variera men även då en felmarginal tas i beaktande är skillnaden i kostnader tydlig. Den konvergerade IT arkitekturen leder till lägre operativa kostnader. Baserat på maturitets analysen kunde det konstateras att problemen relaterar till kommunikation, processartikulation, och bristande helhetskunskap. En del risker kunde minimeras med en konvergerad IT arkitektur, scenario 2, eftersom leverantörhanteringen skulle centraliseras och därmed bli mindre komplex. Däremot är de flesta rekommendationerna aktuella för båda scenarier, såsom formalisering och standardisering av samarbetspraxis, omvärdering av kontrakt för att möta dagens krav, definiering och kommunikation av roller och ansvarsområden, och definiering och artikulation av kommunikations praxis

Contribución a la estimulación del uso de soluciones Cloud Computing: Diseño de un intermediador de servicios Cloud para fomentar el uso de ecosistemas distribuidos digitales confiables, interoperables y de acuerdo a la legalidad. Aplicación en entornos multi-cloud.

184 p.El objetivo del trabajo de investigación presentado en esta tesis es facilitar a los desarrolladores y operadores de aplicaciones desplegadas en múltiples Nubes el descubrimiento y la gestión de los diferentes servicios de Computación, soportando su reutilización y combinación, para generar una red de servicios interoperables, que cumplen con las leyes y cuyos acuerdos de nivel de servicio pueden ser evaluados de manera continua. Una de las contribuciones de esta tesis es el diseño y desarrollo de un bróker de servicios de Computación llamado ACSmI (Advanced Cloud Services meta-Intermediator). ACSmI permite evaluar el cumplimiento de los acuerdos de nivel de servicio incluyendo la legislación. ACSmI también proporciona una capa de abstracción intermedia para los servicios de Computación donde los desarrolladores pueden acceder fácilmente a un catálogo de servicios acreditados y compatibles con los requisitos no funcionales establecidos.Además, este trabajo de investigación propone la caracterización de las aplicaciones nativas multiNube y el concepto de "DevOps extendido" especialmente pensado para este tipo de aplicaciones. El concepto "DevOps extendido" pretende resolver algunos de los problemas actuales del diseño, desarrollo, implementación y adaptación de aplicaciones multiNube, proporcionando un enfoque DevOps novedoso y extendido para la adaptación de las prácticas actuales de DevOps al paradigma multiNube

SLA-based trust model for secure cloud computing

Cloud computing has changed the strategy used for providing distributed services to many business and government agents. Cloud computing delivers scalable and on-demand services to most users in different domains. However, this new technology has also created many challenges for service providers and customers, especially for those users who already own complicated legacy systems. This thesis discusses the challenges of, and proposes solutions to, the issues of dynamic pricing, management of service level agreements (SLA), performance measurement methods and trust management for cloud computing.In cloud computing, a dynamic pricing scheme is very important to allow cloud providers to estimate the price of cloud services. Moreover, the dynamic pricing scheme can be used by cloud providers to optimize the total cost of cloud data centres and correlate the price of the service with the revenue model of service. In the context of cloud computing, dynamic pricing methods from the perspective of cloud providers and cloud customers are missing from the existing literature. A dynamic pricing scheme for cloud computing must take into account all the requirements of building and operating cloud data centres. Furthermore, a cloud pricing scheme must consider issues of service level agreements with cloud customers.I propose a dynamic pricing methodology which provides adequate estimating methods for decision makers who want to calculate the benefits and assess the risks of using cloud technology. I analyse the results and evaluate the solutions produced by the proposed scheme. I conclude that my proposed scheme of dynamic pricing can be used to increase the total revenue of cloud service providers and help cloud customers to select cloud service providers with a good quality level of service.Regarding the concept of SLA, I provide an SLA definition in the context of cloud computing to achieve the aim of presenting a clearly structured SLA for cloud users and improving the means of establishing a trustworthy relationship between service provider and customer. In order to provide a reliable methodology for measuring the performance of cloud platforms, I develop performance metrics to measure and compare the scalability of the virtualization resources of cloud data centres. First, I discuss the need for a reliable method of comparing the performance of various cloud services currently being offered. Then, I develop a different type of metrics and propose a suitable methodology to measure the scalability using these metrics. I focus on virtualization resources such as CPU, storage disk, and network infrastructure.To solve the problem of evaluating the trustworthiness of cloud services, this thesis develops a model for each of the dimensions for Infrastructure as a Service (IaaS) using fuzzy-set theory. I use the Takagi-Sugeno fuzzy-inference approach to develop an overall measure of trust value for the cloud providers. It is not easy to evaluate the cloud metrics for all types of cloud services. So, in this thesis, I use Infrastructure as a Service (IaaS) as a main example when I collect the data and apply the fuzzy model to evaluate trust in terms of cloud computing. Tests and results are presented to evaluate the effectiveness and robustness of the proposed model

A Taxonomy of Quality Metrics for Cloud Services

[EN] A large number of metrics with which to assess the quality of cloud services have been proposed over the last years. However, this knowledge is still dispersed, and stakeholders have little or no guidance when choosing metrics that will be suitable to evaluate their cloud services. The objective of this paper is, therefore, to systematically identify, taxonomically classify, and compare existing quality of service (QoS) metrics in the cloud computing domain. We conducted a systematic literature review of 84 studies selected from a set of 4333 studies that were published from 2006 to November 2018. We specifically identified 470 metric operationalizations that were then classified using a taxonomy, which is also introduced in this paper. The data extracted from the metrics were subsequently analyzed using thematic analysis. The findings indicated that most metrics evaluate quality attributes related to performance efficiency (64%) and that there is a need for metrics that evaluate other characteristics, such as security and compatibility. The majority of the metrics are used during the Operation phase of the cloud services and are applied to the running service. Our results also revealed that metrics for cloud services are still in the early stages of maturity only 10% of the metrics had been empirically validated. The proposed taxonomy can be used by practitioners as a guideline when specifying service level objectives or deciding which metric is best suited to the evaluation of their cloud services, and by researchers as a comprehensive quality framework in which to evaluate their approaches.This work was supported by the Spanish Ministry of Science, Innovation and Universities through the Adapt@Cloud Project under Grant TIN2017-84550-R. The work of Ximena Guerron was supported in part by the Universidad Central del Ecuador (UCE), and in part by the Banco Central del Ecuador.Guerron, X.; Abrahao Gonzales, SM.; Insfran, E.; Fernández-Diego, M.; González-Ladrón-De-Guevara, F. (2020). A Taxonomy of Quality Metrics for Cloud Services. IEEE Access. 8:131461-131498. https://doi.org/10.1109/ACCESS.2020.3009079S131461131498

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

Designing Monitoring Systems for Continuous Certification of Cloud Services: Deriving Meta-requirements and Design Guidelines

Continuous service certification (CSC) involves the consistently gathering and assessing certification-relevant information about cloud service operations to validate whether they continue to adhere to certification criteria. Previous research has proposed test-based CSC methodologies that directly assess the components of cloud service infrastructures. However, test-based certification requires that certification authorities can access the cloud infrastructure, which various issues may limit. To address these challenges, cloud service providers need to conduct monitoring-based CSC; that is, monitor their cloud service infrastructure to gather certification-relevant data by themselves and then provide these data to certification authorities. Nevertheless, we need to better understand how to design monitoring systems to enable cloud service providers to perform such monitoring. By taking a design science perspective, we derive universal meta-requirements and design guidelines for CSC monitoring systems based on findings from five expert focus group interviews with 33 cloud experts and 10 one-to-one interviews with cloud customers. With this study, we expand the current knowledge base regarding CSC and monitoring-based CSC. Our derived design guidelines contribute to the development of CSC monitoring systems and enable monitoring-based CSC that overcomes issues of prior test-based approaches

SaaS-palvelun konfigurointi ja kustomointi: konfiguroinninhallintatyökalu digitaaliselle allekirjoituspalvelulle

Today, cloud computing – a result of combining existing technologies – is a popular paradigm that has brought many benefits for users and enterprises. Cloud computing fosters the provision and use of IT infrastructure, platforms, and applications of any kind in the form of services that are available on the Web. Expensive initial hardware and software investments are not necessary anymore as the resources can be acquired as a service from cloud providers with a pay-per-use pricing model. One aspect that cannot be overlooked in cloud computing is multi-tenancy. It is a property of a system where multiple customers, so-called tenants, transparently share the system's resources. It leverages economies of scale where users and cloud providers benefit from reduced costs, which is a result of higher system density and increased utilization rate of resources. This model surpasses the traditional methods of using single-tenant architecture and ASP model in which a single instance or server is provisioned solely for one customer. Customizability is an essential part of multi-tenant systems. Ideally cloud application vendors wish that every user would be satisfied with the standardized offering, but usually users have their own unique business needs. Customizability can be divided into configuration, which supports differentiation by pre-defined scope, and customization, which supports tenant's custom code. Software variations can be applied to user interface, business logic related workflows, underlying data and reporting utilities. Multi-tenancy shares a lot in common with software product line engineering. However, implementing multi-tenancy and supporting differentiation between tenants have to be carefully planned. Increased complexity may have an impact in maintenance costs and re-engineering costs can be significant. Goal of the thesis is to first examine the requirements for a multi-tenant application, and based on the research, to develop a prototype of a configuration management tool in order to solve the customization need produced by tenants' unique business requirements. The target environment consists of a new SaaS service called SignHero, which is a digital signature service suited for companies that want to shift their signing process to modern times. The scope includes three variability points: customizing the logo in the signing page, customizing the logo in the emails and saving a default workflow. The developed tool fulfills the requirements, and the main service was extended to apply the saved configurations. The implementation leaves many improvement possibilities related to customizability and cloud characteristics. Findings promote the fact that customizability has to be initially included in the product design