Virtualization technology is the backbone of cloud systems, the fastest-growing energy consumers, globally. It holds an imperative position in the resource management area by providing solutions for many related critical problems and challenges. Resource consolidation remains one of the techniques most used to develop new and more efficient resource management policies. Virtual machine packing, which is mainly addressed, allows cloud data centers to move from a particular state to a more optimized one. Currently, the unprecedented advancements in container-based cloud and containerized workloads have created new consolidation opportunities. In this article, we study the problem of consolidating data centers within distributed cloud systems. We give a generic view on IT consolidation at different levels of cloud services. Firstly, we present an overview of virtualized data centers and consolidation. Next, we present a brief thematic taxonomy and an illustration of some consolidation solutions from the literature. This presentation will then be followed by a discussion of certain research questions as well as a proposal for a certain number of future orientations in this field which we assume essential in order to contribute to the resolution of the problematic dealt with in this article.

虚拟化技术是全球增长最快的能源消耗者云系统的基础。通过为许多相关的关键问题和挑战提供解决方案，它在资源管理领域具有至关重要的地位。资源整合仍然是最常用于开发新的和更有效的资源管理策略的技术之一。主要解决的虚拟机打包允许云数据中心从特定状态转移到更优化的状态。当前，基于容器的云和容器化工作负载的空前发展创造了新的整合机会。在本文中，我们研究了在分布式云系统中整合数据中心的问题。我们对不同级别的云服务上的IT整合给出了一般性的看法。首先，我们概述了虚拟化数据中心和整合。接下来，我们介绍一个简短的主题分类法，并从文献中举例说明一些合并解决方案。然后，在此演示文稿之后，将讨论某些研究问题以及对该领域中某些未来方向的建议，我们认为这是必不可少的，以便为解决本文中所讨论的问题做出贡献。