Cloud computing is largely adopted by the current computing industry. Not only users can benefit from cloud scalability, but also businesses are more and more attracted by its flexibility. In addition, the number of offered cloud services (e.g., SaaS, BPaaS, mobile services, etc.) is continuously growing. This raises a question about how to effectively arrange and place them in the cloud, in order to offer high-performance services. Indeed, companies’ and providers’ benefits are strongly related to the optimal placement and management of cloud services, together with their related data. This produces various challenges, including the heterogeneity and dynamicity of hosting cloud zones, the cloud/service -specific placement constraints, etc. Recent cloud service placement approaches have dealt with these issues through different techniques, and by fixing various criteria to optimize. Moreover, researchers have considered other specificities, like the cloud environment type, the deployment model and the placement mode. This paper provides a comprehensive survey on service placement schemes in the cloud. We also identify the current challenges for different cloud service models and environments, and we provide our future directions.

云计算在很大程度上被当前的计算行业所采用。不仅用户可以从云的可扩展性中受益，企业也越来越被它的灵活性所吸引。此外，提供的云服务（例如，SaaS、BPaaS、移动服务等）的数量也在不断增长。这就提出了一个问题，即如何将它们有效地安排和放置在云中，以提供高性能的服务。事实上，公司和供应商的利益与云服务及其相关数据的最佳放置和管理密切相关。这产生了各种挑战，包括托管云区域的异构性和动态性、特定于云/服务的放置约束等。最近的云服务放置方法通过不同的技术处理了这些问题，并通过固定各种标准进行优化。此外，研究人员还考虑了其​​他特殊性，例如云环境类型、部署模型和放置模式。本文对云中的服务放置方案进行了全面调查。我们还确定了不同云服务模型和环境的当前挑战，并提供了我们未来的方向。