Abstract-The accelerating progress of network speed, reliability and security creates an increasing demand to move software and services from being stored and processed locally on users' machines to being managed by third parties that are accessible through the network. This has created the need to develop new software development methods and software architectural styles that meet these new demands. One such example in software architectural design is the recent emergence of the microservices architecture to address the maintenance and scalability demands of online service providers. As microservice architecture is a new research area, the need for a systematic mapping study is crucial in order to summarise the progress so far and identify the gaps and requirements for future studies. In this paper we present a systematic mapping study of microservices architectures and their implementation. Our study focuses on identifying architectural challenges, the architectural diagrams/views and quality attributes related to microsevice systems.

Abstract-Isolating fine-grained business functionalities by boundaries into entities called microservices is a core activity underlying microservitization. We define microservitization as the paradigm shift towards microservices. Determining the optimal microservice boundaries (i.e. microservice granularity) is among the key microservitization design decisions that influence the Quality of Service (QoS) of the microservice application at runtime. In this paper, we provide an architecturecentric approach to model this decision problem. We build on ambients -a modelling approach that can explicitly capture functional boundaries and their adaptation. We extend the aspect-oriented architectural meta-modelling approach of ambients -AMBIENT-PRISMA -with microservice ambients. A microservice ambient is a modelling concept that treats microservice boundaries as an adaptable first-class entity. We use a hypothetical online movie subscription-based system to capture a microservitization scenario using our aspectoriented modelling approach. The results show the ability of microservice ambients to express the functional boundary of a microservice, the concerns of each boundary, the relationships across boundaries and the adaptations of these boundaries. Additionally, we evaluate the expressiveness and effectiveness of microservice ambients using criteria from Architecture Description Language (ADL) classification frameworks since microservice ambients essentially support architecture description for microservices. The evaluation focuses on the fundamental modelling constructs of microservice ambients and how they support microservitization properties such as utility-driven design, tool heterogeneity and decentralised governance. The evaluation highlights how microservice ambients support analysis, evolution and mobility/location awareness which are significant to quality-driven microservice granularity adaptation. The evaluation is general and irrespective of the particular application domain and the business competencies in that domain.

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Architecting software systems is an integral part of the software development lifecycle. However, often the implementation of the resultant software ends up diverging from the designed architecture due to factors such as time pressures on the development team during implementation/evolution, or the lack of architectural awareness on the part of (possibly new) programmers. In such circumstances, the quality requirements addressed by the as-designed architecture are likely to be unaddressed by the as-implemented system. This paper reports on in-vivo case studies of the ACTool, a tool which supports real-time Reflexion Modeling for architecture recovery and on-going consistency. It describes our experience conducting architectural recovery sessions on three deployed, commercial software systems in two companies with the tool, as a first step towards ongoing architecture consistency in these systems. Our findings provide the first in-depth characterization of real-time Reflexion-based architectural recovery in practice, highlighting the architectural recovery agendas at play, the modeling approaches employed, the mapping approaches employed and characterizing the inconsistencies encountered. Our findings also discuss the usefulness of the ACTool for these companies.

Micro service architectures are rapidly establishing themselves in the software industry as a more efficient and effective substitute for monolithic applications. In a micro service architecture, the application is broken down into many small elements called micro services. These are managed in a distributed way and typically involve several development teams. In such an environment, an architectural model can get lost along the way, making it difficult to perform many downstream software engineering tasks, such as migration, audit, integration or impact analysis. To address this problem, we are developing support for Micro Service Architecture Recovery (MiSAR) using a Model Driven Engineering approach. In this paper, we describe an empirical study which aims to identify the core elements of our approach, by undertaking manual analysis on 8 micro service-based open source projects. From this analysis, we define a metamodel for micro service-based architectures and a set of mapping rules which map between the software and the metamodel. The resulting metamodel and mapping rules provide a solid foundation for any micro service architecture recovery approach and hence are a key first step towards managing the architectural integrity of micro servicebased applications.