Cluster Lifecycle and Highly Available Control Plane

Introduction

This lesson continues the Cluster Architecture, Installation & Configuration domain (25% of the CKA, Kubernetes v1.35). The official curriculum asks you to manage the lifecycle of a Kubernetes cluster using kubeadm: upgrade clusters, implement a highly available control plane, and operate etcd including backup and restore. These are classic hands-on exam tasks: "upgrade the control plane node to version X", "take an etcd snapshot to this path", "drain this node before maintenance". Each of them has a precise command sequence, and small ordering mistakes cost points.