Quality of Service Conflict During Web Service Monitoring: A Case Study

AbstractWeb services have become one of the most used technologies in service-oriented systems. Its popularity is due to its property to adapt to any context. As a consequence of the increasing number of Web services on the Internet and its important role in many applications today, Web service quality has become a crucial requirement and demanded by service consumers. Terms of quality levels are written between service providers and service consumers to ensure a degree of quality. The use of monitoring tools to control service quality levels is very important. Quality attributes suffer variations in their values during runtime, this is produced by many factors such as a memory leak, deadlock, race data, inconsistent data, etc. However, sometimes monitoring tools can impact negatively affecting the quality of service when they are not properly used and configured, producing possible conflicts between quality attributes. This paper aims to show the impact of monitoring tools over service quality, two of the most important quality attributes – performance and accuracy – were chosen to be monitored. A case study is conducted to present and evaluate the relationship between performance and accuracy over a Web service. As a result, conflict is found between performance and accuracy, where performance was the most affected, because it presented a degradation in its quality level during monitoring

Verkkojärjestelmien seurantatyökalujen kehittäminen

With increasing amounts of software services provided to users and the more demanding requirements needed from them, monitoring of services is becoming increasingly important. Web service monitoring is the process of confirming system functionality by studying its various attributes, such as availability, reliability, and performance. Monitoring the services helps the software developers, maintainers and owners as they allow for increased reliability, robustness and possibly performance analysis. This thesis focuses on web service monitoring and the tools that it is done with. Specific goals are to learn about the different categories that monitoring services can take and to showcase a custom web service monitoring tool and its further development. The subject is important to the case company LogiNets, which has specific monitoring requirements that need to be fulfilled. These goals were achieved by researching literature on different types of monitoring tools for a literature review and then doing a case study of monitoring tool development. The case study was done about adding a new functionality to LogiNets’s indoor web service monitoring tool called Agent. The literature review was successful in identifying different categories of monitoring tools both by their location relative to the monitored service as well as by the quality of service requirements they fulfill. The review did not, however, discover significant research about existing commercial monitoring tools, and thus provided little help in the case study. The case study was more successful, with the new functionality added and similar extensions planned for the future

KRISEM : a cloud solution for service watchdog

textAs companies continue to grow and expand, Information Technology professionals must constantly ensure the integrity and availability of vital automated services (e.g., HTTP, air traffic control systems etc.). To ensure availability, key automated services needed to keep the organization operational must be monitored continuously. Factors such as program failure and operating system maintenance can cause these services to crash. Services need to be restarted immediately to keep the business operational. There are a variety of automated service monitoring solutions available, but those with universal applicability are of particular interest. The drawbacks of these systems have been their resource limitations as well as the need for complex configuration to make their outage data available from any location. A solution based in the cloud could remove many resource constraints and more easily achieve widespread applicability. This report presents KRISEM, a cloud-based service management approach and application which provides monitoring for services running on remote servers while bypassing many limitations and otherwise necessary configurations to achieve widespread ease of deployment in its pursuit of ensuring higher services availability. User was able to monitor machine to machine communication gateway for Gardner Airport air traffic control system located at Springfield, Missouri with less than 30 minutes configuration time and it recovered from a crash in 2.5 seconds. The application provides all the necessary functionality such as: monitoring, alert notification, data visualization and archiving. The report presents the concept, design, implementation and envisioned future extensions to KRISEM.Electrical and Computer Engineerin

Monitoring the quality of service to support the service based system lifecycle

Service Oriented Computing (SOC) has been established in the last recent years as a successful paradigm in Software Engineering. The systems built under this paradigm, known as Service Based System (SBS), are composed of several services, which are usually third-party software run by external service providers. SBS rely on these service providers to ensure that their services comply with the agreed Quality of Service (QoS). In contrast to other systems, the dynamic behaviour of SBS requires up-to-date QoS information for its proper management in the different stages of its lifecycle, from their initial construction until their decommission. Providing such QoS information has resulted in different technological solutions built around a monitor. Nonetheless, several research challenges in the field remain still open, ranging from theoretical aspects of quality assurance to architectonical challenges in decentralized monitoring. Based on the current research challenges for service monitoring, the research gaps in which we aim to contribute are twofold: - To investigate on the definition and structure of the different quality factors of services, and provide a framework of common understanding for the definition of what to monitor. - To investigate on the different features required to support the activities of the whole SBS lifecycle (i.e. how to monitor), and develop a monitoring framework that accomplishes such features. As a result of this thesis, we provide: What to monitor - A distribution of the quality models along the time dimension and the identification of their relationships. - An analysis of the size and definition coverage of the proposed quality models. - A quantified coverage of the different ISO/IEC 25010 quality factors given by the proposals. - The identification of the most used quality factors, and provided the most consolidated definitions for them. How to monitor - The elicitation of the requirements of the different activities in the SBS lifecycle. - The definition of the set of features that supports the elicited requirements. - A modular service-oriented monitoring framework, named SALMon, implementing the defined features. SALMon has been validated by including it in several frameworks supporting the different activities of the SBS lifecycle. Finally, we have conducted a performance evaluation of SALMon over real web services.La Computació Orientada a Serveis (SOC) ha esdevingut en els darrers anys un paradigma exitós en el camp de l'Enginyeria del Software. Els sistemes construïts sota aquest paradigma, coneguts com Sistemes Basats en Serveis (SBS), estan composats de diversos serveis, que són, usualment, programari de tercers executats per proveïdors de serveis externs. Els SBS depenen dels proveïdors dels serveis per garantir que els serveis compleixen amb la Qualitat del Servei (QoS) acordada. En contrast amb altres sistemes, el comportament dinàmic dels SBS requereix d'informació actualitzada del QoS per a la correcta administració de les diferents etapes del cicle de vida dels SBS: des de la seva construcció inicial fins a la seva clausura. Proveir d'aquesta informació de QoS ha resultat en diferents solucions tecnològiques construïdes al voltant d'un monitor. Malgrat això, diversos reptes de recerca en el camp encara romanen obertes, des d'aspectes teòrics de l'assegurança de qualitat, a reptes arquitectònics en la monitorització descentralitzada. Basat en els reptes de recerca actuals per a la monitorització de serveis, els forats de recerca en els que pretenem contribuir són dobles: - Investigar en la definició i estructura dels diferents factors de qualitat dels serveis, i proveir un marc de treball d'entesa comuna per a la definició de què monitoritzar. - Investigar en les diferents característiques requerides per donar suport a les activitats de tot el cicle de vida dels SBS (i.e. com monitoritzar), i desenvolupar una plataforma de monitorització que acompleixi aquestes característiques. Com a resultats de la tesis, proveïm: Què monitoritzar - Una distribució dels models de qualitat al llarg de la dimensió temporal i la identificació de les seves interrelacions. - Un anàlisi de la mida i definició de la cobertura dels models de qualitat proposats. - Una cobertura quantificada dels diferents factors de qualitat ISO/IEC 25010 donat en les diferents propostes. - La identificació dels factors de qualitat més utilitzats, i la definició dels termes més consolidats. Com monitoritzar - L'elicitació dels requeriments per a les diferents activitats en el cicle de vida dels SBS. - La definició del conjunt de característiques que donen suport als requeriments elicitats. - Una platforma modular orientada a serveis, anomenat SALMon, que implementa les característiques definides. SALMon ha estatvalidat incloent la plataforma en diversos marcs de treball donant suport a les diferents activitat

The knowledge management in small and medium enterprises and the quality management approaches in service-oriented architecture

The thesis is organized into two different sections: the first one deals with the knowledge management (KM) in small and medium enterprises (SMEs), the second one deals with the quality management approaches in Service Oriented Architecture (SOA). The first research topic arises from the awareness that knowledge fertilization is crucial for SMEs competitiveness and to improve network collaboration. Nevertheless, while there is an abundance of studies describing how large companies are successfully exploiting knowledge management practices, regarding SMEs the framework is still fragmented. The Ph.D. program has been aimed at publishing two journal articles: the first one is a literature review, which provides the state of art of KM in SMEs and the second one is an empirical paper, which addresses the research questions emerging from the analysis of the literature review. The research questions concern the barriers hindering the spread of KM practices in SMEs, the main knowledge management systems (KMSs) adopted by SMEs and the impact of the use of KM practices on SME performance; they were subsequently addressed through a field analysis conducted on a sample of SMEs, adopting fuzzy set theory as methodology. Therefore the first section of this thesis is structured as a collection of these two published articles. The second section deals with the quality management approaches in Service-Oriented Architecture (SOA), this research topic arises from the needs to investigate services quality techniques since there is a vast literature concerning the software quality metrics within an object-oriented environment, but this framework cannot be applied to SOA systems. This study attempted to fill this gap presenting the results of a literature review on this topic; the outcomes of the review provide a valuable understanding of the best researched areas and the areas of SOA quality which are poorly investigated. In order to give an answer to one of the retrieved research questions emerging from the analysis of the literature review and concerning the lack of case studies, an empirical analysis on SOA services performance has been carried out in an important telecommunications company by an efficiency analysis. Finally the work’ conclusions are presented which sum up both the knowledge management prospect that the SOA prospect

FlexMonitorWS : a solution for monitoring Web services with a focus on QoS attributes

Orientador: Cecília Mary Fischer RubiraDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: Serviços Web são usados como uma das formas de se obter uma Arquitetura Orientada a Serviços (SOA). Com aspectos interoperáveis, dinâmicos e distribuídos, tais serviços agregam valores de negócio, são unidades de software com alta coesão e são utilizados para integração entre aplicações empresariais. Em um contexto de SOA, provedores de serviços devem oferecer garantias de funcionamento de seus serviços. Esta garantia é realizada através de atributos de Quality of Service (QoS) inseridos em contratos do tipo SLA (Service Level Agreement). Atributos de QoS podem ter flutuações ou mudança de estado ao longo do tempo, dado que um serviço opera em um ambiente de alta dinamicidade e alta imprevisibilidade que são propriedades inerentes ao contexto SOA. Diante deste cenário, há uma clara necessidade de se conhecer as variações que ocorrem nos atributos de QoS. Para isso, é fundamental aplicar uma monitoração que possibilite conhecer os valores de atributos de QoS para compreender o contexto geral do ambiente que opera o serviço. Uma boa solução de monitoração deve oferecer meios flexíveis de monitorar diferentes atributos de QoS (e.g. disponibilidade, desempenho e confiabilidade), de diferentes modos de operar, considerando diferentes alvos ligados ao serviço (e.g. servidor, rede e aplicação servidora). Por meio de uma Revisão Sistemática da Literatura identificamos que as soluções encontradas não apoiam a flexibilidade na monitoração. Face a este contexto, esta dissertação propôs a FlexMonitorWS uma solução de monitoração de serviços Web e de recursos de infraestrutura de TI ligada ao serviço Web. A FlexMonitorWS adota técnicas de Linhas de Produtos de Software para criar uma família de monitores a partir da variabilidade de software existente em sistemas de monitoração de serviços Web. Três estudos de caso foram executados para avaliar a viabilidade da ferramenta, obtendo-se resultados satisfatórios na entrega de valores de atributos de QoS e na compreensão do ambiente que opera o serviço Web. Ao final, apresentamos conclusões, contribuições e direções para trabalhos futurosAbstract: Web services are used as a way of obtaining a Service Oriented Architecture (SOA). With interoperable, dynamic and distributed aspects such services add business values are software units with high cohesion and are used to integrate business applications. In a SOA context, service providers must offer guarantees of the servces operations. This warranty is carried out by attributes Quality of Service (QoS) type contracts entered into SLA (Service Level Agreement). QoS attributes can have fluctuations or changes of state over time, given that a service operates in an environment of high dynamics and high unpredictability inherent in the SOA context properties. Given this scenario, there is a clear need to understand the fluctuations in the QoS attributes. Therefore, it is essential to apply a monitoring which allows to know the QoS attributes values to understand the overall context of the environment that operates the service. A good monitoring solution must offer flexible ways to monitor different QoS attributes (e.g. performance, availability and reliability) in different ways to operate, considering different targets linked to the service (e.g. server, network and server application). By analyzing existing solutions through a Systematic Literature Review identified that solutions do not support the flexibility in monitoring. Against this background, this thesis proposed a solution FlexMonitorWS monitoring of Web services and IT infrastructure resources connected to the Web services. FlexMonitorWS adopts techniques from Software Product Lines to create a monitors family from the existing variability in the Web services monitoring systems. Three case studies were performed to assess the tool feasibility, obtaining satisfactory results in delivering QoS attributes values and understanding to environment that operates the Web service. In the end, conclusions, contributions and directions for future work are presentedMestradoCiência da ComputaçãoMestre em Ciência da Computaçã