Introduction Kubernetes clusters are powerful, and that power comes with risk. A single misconfigured service account can give an attacker access to every secret in your cluster. A developer with overly broad permissions can accidentally delete production workloads. In multi-tenant environments, one team's deployment can interfere with another's. Role-Based Access Control (RBAC) is how you prevent all of this. RBAC in Kubernetes lets you define exactly who can do what, in which namespaces, down to individual API verbs on specific resource types. Despite its importance, RBAC is one of the most commonly misconfigured parts of Kubernetes. I regularly see clusters where every service account has cluster-admin privileges, where namespaces share the same service accounts, or where RBAC policies were copied from a blog post without understanding what they grant. This guide walks through RBAC from the ground up, with real manifests you can apply to your clusters today.…