Namespaces

Namespaces in Kubernetes allow you to divide cluster resources between multiple users or teams. They provide logical isolation and help with multi-tenancy, access control, and resource management.

When to Use Namespaces

Namespaces are useful when:

  • You need to isolate environments (e.g., dev, staging, prod)
  • You want to enforce resource quotas and limits
  • You want to implement RBAC per team or application

Tip

For most small or single-team clusters, the default namespace is sufficient.

Viewing Namespaces

kubectl get namespaces

Or with shorthand:

kubectl get ns

Creating a Namespace

apiVersion: v1
kind: Namespace
metadata:
  name: dev-team

Apply it:

kubectl apply -f namespace.yaml

Using Namespaces with kubectl

kubectl get pods -n dev-team
kubectl create deployment nginx --image=nginx -n dev-team

To temporarily switch namespace context:

kubectl config set-context --current --namespace=dev-team

Default Namespaces

Namespace Purpose
default Used when no other namespace is specified
kube-system Kubernetes control plane components (DNS, scheduler)
kube-public Readable by all users, often used for public bootstrap
kube-node-lease Heartbeats for node status

Namespaced vs Cluster-Scoped Resources

Some resources must live in a namespace, others are cluster-scoped.

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

Resource Quotas and Limits

You can enforce limits on namespaces using:

  • ResourceQuota: caps total resources in the namespace
  • LimitRange: sets default limits per Pod/container

Example:

apiVersion: v1
kind: ResourceQuota
metadata:
  name: compute-quota
  namespace: dev
spec:
  hard:
    requests.cpu: "2"
    limits.memory: 4Gi

Cleanup

To delete a namespace and everything inside it:

kubectl delete namespace dev-team

Summary

  • Namespaces provide logical isolation for teams, environments, or applications.
  • Use namespaces to set resource quotas, apply RBAC, and organize your cluster.
  • For small/simple clusters, the default namespace is fine; use more as you scale.

Tip

Name namespaces clearly (e.g., dev, prod, team-a) and use them to enforce security and resource policies.