Namespaces partition a cluster into virtual sub-clusters, providing resource isolation, RBAC scope, and network policy boundaries between teams or environments.

Common patterns: separate namespaces per environment (dev, staging, prod) in the same cluster, or per team (platform-team, data-team). RBAC policies grant access within a namespace without cluster-wide permissions. ResourceQuotas limit CPU and memory per namespace - preventing one team from starving another. Services in different namespaces communicate via service-name.namespace.svc.cluster.local .