Namespaces

A virtual cluster inside the cluster: a name scope for objects, and the place to attach quotas, RBAC and network policies.

graph TB subgraph cluster subgraph ns1 [namespace: dev] P1[pod web] --- P2[pod db] end subgraph ns2 [namespace: prod] P3[pod web] --- P4[pod db] end N[nodes, PVs, StorageClasses - not namespaced] end

kubectl get ns
kubectl create ns dev
kubectl get pods -n dev
kubectl get pods -A
kubectl config set-context --current --namespace=dev
kubectl api-resources --namespaced=false        # what lives outside namespaces

Namespaced	Cluster-scoped
Pods, Deployments, Services, ConfigMaps, Secrets, PVCs, Roles	Nodes, PersistentVolumes, StorageClasses, ClusterRoles, CRDs, Namespaces

Built in: default, kube-system, kube-public, kube-node-lease. Never deploy your own work into kube-system.

Names are unique per kind per namespace - dev and prod can both have web. A Service in another namespace is reachable as web.prod.svc.cluster.local (Day 2).

Warning

Deleting a namespace deletes everything in it - no confirmation, no undo. Check kubectl config get-contexts first.

References

Namespaces