Serverless software engineering – and how to get there

Serverless computing is on the rise but developing software to exploit this space involves a deep rethink of software architecture, deployment, and operation (perhaps also, software development processes and team structures). Central to this revolution, we find a compelling argument for distributed, services-based software architectures. But converting a large, established monolith architecture system to microservices is non-trivial and fraught with both cost and risk. For the many firms with established software systems, this architectural system conversion might be considered the first stop-off on the journey to serverless computing. In tandem, software deployment and production monitoring also require reinvention. The focus of this paper involves an examination of the advantages of microservices architectures, include techniques for migrating from monolith architectures. Through application of a Multivocal Literature Review (MLR), we find that migrating from a monolith architecture to a microservices architecture is risky and non-trivial, but that there are techniques that can be employed to support the transition. We find also that monoliths have their advantages which might be overlooked to some extent in the race to serverless computing

Road to Microservices

This document intends to elucidate the complexity of microservices decomposition and this its inherent process of implementation. Developments in technology and design, achieving higher performance, reliability, or lowering costs are valid reasons to consider controlling the product’s quality by guaranteeing its conformance with established characteristics and standards. Control is made possible by adding quality control, inspection routines, and trend analysis to a manufacturing process. These techniques are established in the Quality field academically and business-wise. Repeat Part Management (RPM) is software that allows users to apply these techniques efficiently and has brought value to the company. However, RPM has been growing, and issues have emerged due to customer needs - accumulated technical debt. These ever-growing modifications are common through different business areas, and architectures’ research evolution has accompanied them. This demand for highly modifiable, rapid development, and independent systems has resulted in the adoption of microservices. There is a concern for existing systems for decomposition due to the characteristics of microservices, which encourages approach/technique research. This architecture promotes legacy system analysis to map current functionalities and dependencies between components. Furthermore, critical concepts in a microservices architecture are researched and implemented in a new system that encompasses Repeat Part Management’s functionalities. This thesis explores the microservices’ architecture evolution with an already defined mature domain in quality assessment.Este documento pretende especificar a complexidade do processo de decomposição em microsserviços e do seu processo de implementação. Avanços na tecnologia e design, alcançar melhor performance, ou a confiabilidade do produto, ou diminuir custos são justificações válidas para considerar controlar a qualidade do produto e, inerentemente, garantir a sua conformidade com as características previamente definidas e com padrões da indústria. É possível garantir controlo sob os produtos ao acrescentar, ao processo produtivo, métodos de controlo de qualidade, rotinas de inspeção e análise de tendências (de desvio). Estas técnicas estão bem estabelecidas academicamente e, de um ponto de vista do mercado, na área da Qualidade e garantia da qualidade. O Repeat Part Management (RPM) é um software que permite aos seus utilizadores a utilização eficiente destas técnicas de qualidade, o que resulta numa adição de valor para a empresa. Porém, devido às crescentes necessidades dos clientes, alguns problemas têm sido identificados - relacionados com o conceito de acumulação de technical debt. Esta crescente necessidade de alteração é comum em diversas áreas de negócio, e a investigação de soluções arquiteturais tem acompanhado esta pesquisa. Esta solução arquitetura pode ser caracterizada pela facilidade de sistemas facilmente modificáveis, pelo rápido desenvolvimento e implementação, e pela independência dos serviços decompostos. Aquando de uma migração para microsserviços num sistema maturo, existe uma maior preocupação na decomposição da aplicação e definição dos serviços dada a característica dos microsserviços, o que incentiva a uma pesquisa detalhada sobre as técnicas de decomposição. Pela mesma razão, esta arquitetura incentiva ao mapeamento e documentação das dependências entre serviços e componentes e o estudo da aplicação legacy. Para além disto, estes conceitos, e a sua implementação devem ser planeados, justificados e documentados, o que explica a complexidade do processo de migração e implementação, que deve ter em consideração as funcionalidades existentes no Repeat Part Management. Dessa forma, esta tese explora a implementação desta arquitetura numa aplicação matura na área de Garantia de Qualidade

Data Management in Microservices: State of the Practice, Challenges, and Research Directions

We are recently witnessing an increased adoption of microservice architectures by the industry for achieving scalability by functional decomposition, fault-tolerance by deployment of small and independent services, and polyglot persistence by the adoption of different database technologies specific to the needs of each service. Despite the accelerating industrial adoption and the extensive research on microservices, there is a lack of thorough investigation on the state of the practice and the major challenges faced by practitioners with regard to data management. To bridge this gap, this paper presents a detailed investigation of data management in microservices. Our exploratory study is based on the following methodology: we conducted a systematic literature review of articles reporting the adoption of microservices in industry, where more than 300 articles were filtered down to 11 representative studies; we analyzed a set of 9 popular open-source microservice-based applications, selected out of more than 20 open-source projects; furthermore, to strengthen our evidence, we conducted an online survey that we then used to cross-validate the findings of the previous steps with the perceptions and experiences of over 120 practitioners and researchers. Through this process, we were able to categorize the state of practice and reveal several principled challenges that cannot be solved by software engineering practices, but rather need system-level support to alleviate the burden of practitioners. Based on the observations we also identified a series of research directions to achieve this goal. Fundamentally, novel database systems and data management tools that support isolation for microservices, which include fault isolation, performance isolation, data ownership, and independent schema evolution across microservices must be built to address the needs of this growing architectural style

From Monolith to Microservices: A Classification of Refactoring Approaches

While the recently emerged Microservices architectural style is widely discussed in literature, it is difficult to find clear guidance on the process of refactoring legacy applications. The importance of the topic is underpinned by high costs and effort of a refactoring process which has several other implications, e.g. overall processes (DevOps) and team structure. Software architects facing this challenge are in need of selecting an appropriate strategy and refactoring technique. One of the most discussed aspects in this context is finding the right service granularity to fully leverage the advantages of a Microservices architecture. This study first discusses the notion of architectural refactoring and subsequently compares 10 existing refactoring approaches recently proposed in academic literature. The approaches are classified by the underlying decomposition technique and visually presented in the form of a decision guide for quick reference. The review yielded a variety of strategies to break down a monolithic application into independent services. With one exception, most approaches are only applicable under certain conditions. Further concerns are the significant amount of input data some approaches require as well as limited or prototypical tool support.Comment: 13 pages, 4 tables, 2 figures, Software Engineering Aspects of Continuous Development and New Paradigms of Software Production and Deployment, First International Workshop, DEVOPS 2018, Chateau de Villebrumier, France, March 5-6, 2018, Revised Selected Paper

Microservices-based IoT Applications Scheduling in Edge and Fog Computing: A Taxonomy and Future Directions

Edge and Fog computing paradigms utilise distributed, heterogeneous and resource-constrained devices at the edge of the network for efficient deployment of latency-critical and bandwidth-hungry IoT application services. Moreover, MicroService Architecture (MSA) is increasingly adopted to keep up with the rapid development and deployment needs of the fast-evolving IoT applications. Due to the fine-grained modularity of the microservices along with their independently deployable and scalable nature, MSA exhibits great potential in harnessing both Fog and Cloud resources to meet diverse QoS requirements of the IoT application services, thus giving rise to novel paradigms like Osmotic computing. However, efficient and scalable scheduling algorithms are required to utilise the said characteristics of the MSA while overcoming novel challenges introduced by the architecture. To this end, we present a comprehensive taxonomy of recent literature on microservices-based IoT applications scheduling in Edge and Fog computing environments. Furthermore, we organise multiple taxonomies to capture the main aspects of the scheduling problem, analyse and classify related works, identify research gaps within each category, and discuss future research directions.Comment: 35 pages, 10 figures, submitted to ACM Computing Survey

Defining Metrics for the Identification of Microservices in Code Repositories

Microsserviços tornaram-se o estilo de arquitetura mais utilizado entre todas as estratégias de desenvolvimento de software disponíveis. No entanto, as pesquisas sobre esse tema estão no início, o que dificulta a localização de aplicações de microsserviços em escala para análise. Portanto, há uma grande necessidade de novas investigações, bem como ferramentas para apoiar novos desenvolvimentos no campo de microsserviços. O primeiro objetivo deste trabalho é coletar características de microsserviços encontradas na literatura e traduzi-las em características mensuráveis no código. Com isso, fornecemos um conjunto abrangente de características, bem como métricas para identificá-las no código. Um segundo objetivo é usar essas métricas para identificar a base do código seguindo um estilo de arquitetura de microsserviço. Essa solução é disponibilizada por meio de uma ferramenta que permite aos usuários encontrar microsserviços em escalas e filtrá-los de acordo com suas necessidades. Isso pode ser usado para encontrar exemplos de microsserviços em uma linguagem de programação específica ou para criar corpora para estudos de pesquisa. Nossa avaliação mostra que nosso algoritmo pode identificar microsserviços com uma precisão de 85%.Microservices have become the most used architectural style among all available software development strategies. However, it is difficult to find microservice applications at scale for analysis. Therefore, there is a great need for new investigations as well as tools to support new developments in the field of microservices. The first goal of this work is to collect microservices characteristics found in the literature and translate them into measurable features in the code. With this, we provide a comprehensive set of characteristics as well as metrics to identify them in the code. A second goal is to design an algorithm to use such metrics to identify code basis following a microservice architectural style. This solution is made available through a tool that allows users to find microservices at scales and filter them according to their needs. This can be used to find examples of microservices in a specific programming language or to create corpora for research studies. Our evaluation shows our algorithm can identify microservices with a precision of 85%

Identification of microservices from monolithic applications through topic modelling

Dissertação de mestrado em Informatics EngineeringMicroservices emerged as one of the most popular architectural patterns in the recent years given the increased need to scale, grow and flexibilize software projects accompanied by the growth in cloud computing and DevOps. Many software applications are being submitted to a process of migration from its monolithic architecture to a more modular, scalable and flexible architecture of microservices. This process is slow and, depending on the project’s complexity, it may take months or even years to complete. This dissertation proposes a new approach on microservices identification by resorting to topic modelling in order to identify services according to domain terms. This approach in combination with clustering techniques produces a set of services based on the original software. The proposed methodology is implemented as an open-source tool for exploration of monolithic architectures and identification of microservices. An extensive quantitative analysis using the state of the art metrics on independence of functionality and modularity of services was conducted on 200 open-source projects collected from GitHub. Cohesion at message and domain level metrics showed medians of roughly 0.6. Interfaces per service exhibited a median of 1.5 with a compact interquartile range. Structural and conceptual modularity revealed medians of 0.2 and 0.4 respectively. Further analysis to understand if the methodology works better for smaller/larger projects revealed an overall stability and similar performance across metrics. Our first results are positive demonstrating beneficial identification of services due to overall metrics’ results.Os microserviços emergiram como um dos padrões arquiteturais mais populares na atualidade dado o aumento da necessidade em escalar, crescer e flexibilizar projetos de software, acompanhados da crescente da computação na cloud e DevOps. Muitas aplicações estão a ser submetidas a processos de migração de uma arquitetura monolítica para uma arquitetura mais modular, escalável e flexivel de microserviços. Este processo de migração é lento, e dependendo da complexidade do projeto, poderá levar vários meses ou mesmo anos a completar. Esta dissertação propõe uma nova abordagem na identificação de microserviços recorrendo a modelação de tópicos de forma a identificar serviços de acordo com termos de domínio de um projeto de software. Esta abordagem em combinação com técnicas de clustering produz um conjunto de serviços baseado no projeto de software original. A metodologia proposta é implementada como uma ferramenta open-source para exploração de arquiteturas monolíticas e identificação de microserviços. Uma análise quantitativa extensa recorrendo a métricas de independência de funcionalidade e modularidade de serviços foi conduzida em 200 aplicações open-source recolhidas do GitHub. Métricas de coesão ao nível da mensagem e domínio revelaram medianas em torno de 0.6. Interfaces por serviço demonstraram uma mediana de 1.5 com um intervalo interquartil compacto. Métricas de modularidade estrutural e conceptual revelaram medianas de 0.2 e 0.4 respetivamente. Uma análise mais aprofundada para tentar perceber se a metodologia funciona melhor para projetos de diferentes dimensões/características revelaram uma estabilidade geral do funcionamento do método. Os primeiros resultados são positivos demonstrando identificações de serviços benéficos tendo em conta que os valores das métricas são de uma forma global positivos e promissores