Microservice Transition and its Granularity Problem: A Systematic Mapping Study

Microservices have gained wide recognition and acceptance in software industries as an emerging architectural style for autonomic, scalable, and more reliable computing. The transition to microservices has been highly motivated by the need for better alignment of technical design decisions with improving value potentials of architectures. Despite microservices' popularity, research still lacks disciplined understanding of transition and consensus on the principles and activities underlying "micro-ing" architectures. In this paper, we report on a systematic mapping study that consolidates various views, approaches and activities that commonly assist in the transition to microservices. The study aims to provide a better understanding of the transition; it also contributes a working definition of the transition and technical activities underlying it. We term the transition and technical activities leading to microservice architectures as microservitization. We then shed light on a fundamental problem of microservitization: microservice granularity and reasoning about its adaptation as first-class entities. This study reviews state-of-the-art and -practice related to reasoning about microservice granularity; it reviews modelling approaches, aspects considered, guidelines and processes used to reason about microservice granularity. This study identifies opportunities for future research and development related to reasoning about microservice granularity.Comment: 36 pages including references, 6 figures, and 3 table

Two ways to Grid: the contribution of Open Grid Services Architecture (OGSA) mechanisms to service-centric and resource-centric lifecycles

Service Oriented Architectures (SOAs) support service lifecycle tasks, including Development, Deployment, Discovery and Use. We observe that there are two disparate ways to use Grid SOAs such as the Open Grid Services Architecture (OGSA) as exemplified in the Globus Toolkit (GT3/4). One is a traditional enterprise SOA use where end-user services are developed, deployed and resourced behind firewalls, for use by external consumers: a service-centric (or ‘first-order’) approach. The other supports end-user development, deployment, and resourcing of applications across organizations via the use of execution and resource management services: A Resource-centric (or ‘second-order’) approach. We analyze and compare the two approaches using a combination of empirical experiments and an architectural evaluation methodology (scenario, mechanism, and quality attributes) to reveal common and distinct strengths and weaknesses. The impact of potential improvements (which are likely to be manifested by GT4) is estimated, and opportunities for alternative architectures and technologies explored. We conclude by investigating if the two approaches can be converged or combined, and if they are compatible on shared resources

Split and Migrate: Resource-Driven Placement and Discovery of Microservices at the Edge

Microservices architectures combine the use of fine-grained and independently-scalable services with lightweight communication protocols, such as REST calls over HTTP. Microservices bring flexibility to the development and deployment of application back-ends in the cloud. Applications such as collaborative editing tools require frequent interactions between the front-end running on users\u27 machines and a back-end formed of multiple microservices. User-perceived latencies depend on their connection to microservices, but also on the interaction patterns between these services and their databases. Placing services at the edge of the network, closer to the users, is necessary to reduce user-perceived latencies. It is however difficult to decide on the placement of complete stateful microservices at one specific core or edge location without trading between a latency reduction for some users and a latency increase for the others. We present how to dynamically deploy microservices on a combination of core and edge resources to systematically reduce user-perceived latencies. Our approach enables the split of stateful microservices, and the placement of the resulting splits on appropriate core and edge sites. Koala, a decentralized and resource-driven service discovery middleware, enables REST calls to reach and use the appropriate split, with only minimal changes to a legacy microservices application. Locality awareness using network coordinates further enables to automatically migrate services split and follow the location of the users. We confirm the effectiveness of our approach with a full prototype and an application to ShareLatex, a microservices-based collaborative editing application

Z39.50 broadcast searching and Z-server response times: perspectives from CC-interop

This paper begins by briefly outlining the evolution of Z39.50 and the current trends, including the work of the JISC CC-interop project. The research crux of the paper focuses on an investigation conducted with respect to testing Z39.50 server (Z-server) response times in a broadcast (parallel) searching environment. Customised software was configured to broadcast a search to all test Z-servers once an hour, for eleven weeks. The results were logged for analysis. Most Z-servers responded rapidly. 'Network congestion' and local OPAC usage were not found to significantly influence Z-server performance. Response time issues encountered by implementers may be the result of non-response by the Z-server and how Z-client software deals with this. The influence of 'quick and dirty' Z39.50 implementations is also identified as a potential cause of slow broadcast searching. The paper indicates various areas for further research, including setting shorter time-outs and greater end-user behavioural research to ascertain user requirements in this area. The influence more complex searches, such as Boolean, have on response times and suboptimal Z39.50 implementations are also emphasised for further study. This paper informs the LIS research community and has practical implications for those establishing Z39.50 based distributed systems, as well as those in the Web Services community. The paper challenges popular LIS opinion that Z39.50 is inherently sluggish and thus unsuitable for the demands of the modern user

XSACd—Cross-domain resource sharing & access control for smart environments

Computing devices permeate working and living environments, affecting all aspects of modern everyday lives; a trend which is expected to intensify in the coming years. In the residential setting, the enhanced features and services provided by said computing devices constitute what is typically referred to as a “smart home”. However, the direct interaction smart devices often have with the physical world, along with the processing, storage and communication of data pertaining to users’ lives, i.e. private sensitive in nature, bring security concerns into the limelight. The resource-constraints of the platforms being integrated into a smart home environment, and their heterogeneity in hardware, network and overlaying technologies, only exacerbate the above issues. This paper presents XSACd, a cross-domain resource sharing & access control framework for smart environments, combining the well-studied fine-grained access control provided by the eXtensible Access Control Markup Language (XACML) with the benefits of Service Oriented Architectures, through the use of the Devices Profile for Web Services (DPWS). Based on standardized technologies, it enables seamless interactions and fine-grained policy-based management of heterogeneous smart devices, including support for communication between distributed networks, via the associated MQ Telemetry Transport protocol (MQTT)–based proxies. The framework is implemented in full, and its performance is evaluated on a test bed featuring relatively resource-constrained smart platforms and embedded devices, verifying the feasibility of the proposed approac

An Overview of Automotive Service-Oriented Architectures and Implications for Security Countermeasures

New requirements from the customers\u27 and manufacturers\u27 point of view such as adding new software functions during the product life cycle require a transformed architecture design for future vehicles. The paradigm of signal-oriented communication established for many years will increasingly be replaced by service-oriented approaches in order to increase the update and upgrade capability. In this article, we provide an overview of current protocols and communication patterns for automotive architectures based on the service-oriented architecture (SOA) paradigm and compare them with signal-oriented approaches. Resulting challenges and opportunities of SOAs with respect to information security are outlined and discussed. For this purpose, we explain different security countermeasures and present a state of the section of automotive approaches in the fields of firewalls, Intrusion Detection Systems (IDSs) and Identity and Access Management (IAM). Our final discussion is based on an exemplary hybrid architecture (signal- and service-oriented) and examines the adaptation of existing security measures as well as their specific security features