설명 및 아키텍처들
https://kubernetes.io/docs/concepts/overview/components/
https://traefik.io/glossary/understanding-multi-cluster-kubernetes/
https://www.cisco.com/c/en/us/support/docs/cloud-systems-management/hybrid-cloud-platform-google-cloud/218456-create-multi-master-kubernetes-cluster-w.html
https://minkukjo.github.io/devops/2020/12/09/Kubernetes15-03/