Cluster Administration Basics

You run kubectl apply -f deployment.yaml and pods spin up. Except they spin up in staging, not production, because your context was still pointed at the wrong cluster from this morning's debugging session. Or a junior engineer accidentally deletes a namespace they shouldn't have access to. Or one team's batch job consumes every CPU core, and three other teams' pods get evicted. These are cluster administration problems, and they're the gap between knowing Kubernetes resources and actually running a cluster.

This article covers four areas that close that gap: kubeconfig contexts for organizing cluster access, RBAC for controlling permissions, cordon and drain for node lifecycle management, and ResourceQuotas for resource governance. The KCNA tests these conceptually. Understanding the "why" here makes the hands-on CKA work straightforward later.