This article explores how distributed microservice systems in the cloud are scaled. The goal is to piece together, from scattered research, working solutions and what might still be experimental. The focus is on design and deployment strategies that aim for reliability, elasticity, and cost-effective growth. Open-access, peer-reviewed papers published since 2021 were reviewed with a special emphasis placed on those with empirical tests, diagrams, or case studies to see how ideas play out in practice. Across the papers certain themes keep reappearing. Infrastructure work revolves around horizontal and vertical scaling, while orchestration and autoscaling — Kubernetes HPA/VPA, serverless computing, various service meshes — are interpreted as part of the broader field. The unique contribution is the attempt to frame old and new together — to see classical ideas such as service modularity alongside hybrid autoscalers, energy-aware verification, probabilistic checks.  In some cases, these tactics reinforce one another; in others they collide, or create unexpected trade-offs. Observing them in the same frame highlights that scaling microservices is as an ongoing experiment, where established patterns and cutting-edge proposals coexist. Taken together, the available studies do not present a single blueprint but instead sketch what looks like a layered approach. In many cases services are kept as stateless and decoupled as possible; in others that ideal is only partly met. Horizontal and vertical scaling appear side by side — sometimes combined in the same system — with their usefulness varying by workload. Orchestration policies are often automated, yet the literature also warns that energy use and security concerns grow quietly in the background as systems expand and, if left unmanaged, can erode the gains of scaling. This article will provide value to cloud architects, DevOps engineers, developers, and researchers interested in gaining awareness of current practices as well as possible venues of where the field might be heading next.

Microservices, Cloud computing, Horizontal scaling, Vertical scaling, Kubernetes, Autoscaling, Serverless computing, Reinforcement learning, Architectural design, Scalability

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