This repository is a companion to the Korean book '컨테이너 인프라 환경 구축을 위한 쿠버네티스/도커' (Kubernetes/Docker for Container Infrastructure). It provides a collection of Vagrant-based lab environments, shell provisioning scripts, Kubernetes YAML manifests, Helm charts, and CI/CD examples (Jenkins) to help readers build and manage Kubernetes clusters on VirtualBox. The codebase includes single-master and multi-master (via Kubespray) cluster setups, along with demonstrations of core Kubernetes concepts (Pods, Services, Ingress, Storage, Monitoring). While the repository is actively maintained with yearly architecture documents, the actual scripts and configurations rely on outdated software versions (e.g., Kubernetes 1.18, Docker 18.06, CentOS 7) and external URLs that may become stale. The code is functional for educational purposes but is boilerplate-heavy and repetitive across chapters, limiting its reusability in production environments.