The Fog computing paradigm utilises 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 fast-evolving IoT applications. Due to the fine-grained modularity of the microservices and their independently deployable and scalable nature, MSA exhibits great potential in harnessing Fog and Cloud resources, thus giving rise to novel paradigms like Osmotic computing. The loosely coupled nature of the microservices, aided by the container orchestrators and service mesh technologies, enables the dynamic composition of distributed and scalable microservices to achieve diverse performance requirements of the IoT applications using distributed Fog resources. To this end, efficient placement of microservice plays a vital role, and scalable placement algorithms are required to utilise the said characteristics of the MSA while overcoming novel challenges introduced by the architecture. Thus, we present a comprehensive taxonomy of recent literature on microservices-based IoT applications placement within Fog computing environments. Furthermore, we organise multiple taxonomies to capture the main aspects of the placement problem, analyse and classify related works, identify research gaps within each category, and discuss future research directions.

翻译：雾计算范式利用网络边缘的分布式、异构且资源受限的设备，高效部署对延迟敏感且带宽需求大的物联网应用服务。同时，微服务架构（MSA）日益被采用，以跟上快速演进的物联网应用的开发和部署需求。得益于微服务的细粒度模块化及其独立部署与可扩展特性，MSA在充分利用雾计算和云计算资源方面展现出巨大潜力，从而催生了渗透计算等新型范式。借助容器编排器和服务网格技术，微服务的松耦合特性支持利用分布式雾资源动态组合分布式可扩展的微服务，以满足物联网应用多样的性能需求。为此，微服务的有效部署至关重要，需要可扩展的部署算法来充分利用MSA的这些特性，同时克服该架构带来的新挑战。因此，我们提出了关于雾计算环境中基于微服务架构的物联网应用部署的最新文献的综合分类法。此外，我们通过组织多种分类法来涵盖部署问题的核心方面，对相关工作进行分析和分类，识别各类别中的研究空白，并讨论未来研究方向。