Create a Kubernetes Namespace

What a namespace is

A namespace is a virtual cluster inside a real cluster. It groups resources, such as pods and services, and keeps teams and projects apart. Namespaces give you:

• Isolation. Teams work without touching each other's resources.
• Quotas. You can limit what each namespace may use.
• Access control. RBAC rules can apply per namespace.

Kubernetes starts with four namespaces:

1. default for objects with no other namespace.
2. kube-system for objects made by Kubernetes itself.
3. kube-public which every user can read, even without sign-in.
4. kube-node-lease which holds lease objects for node health.

Create one with kubectl

You need a running cluster. For tests, you can use Minikube on your own machine.

kubectl create namespace my-namespace

List the namespaces to check:

kubectl get namespaces

Create one with a YAML file

A file is easier to keep and share. Save this as namespace.yaml:

apiVersion: v1
kind: Namespace
metadata:
  name: my-namespace
  labels:
    name: my-namespace

Apply it:

kubectl apply -f namespace.yaml

Work with namespaces

Delete a namespace (this also deletes everything inside it):

kubectl delete namespace my-namespace

Use a namespace for a command:

kubectl get pods -n my-namespace

Switch the default namespace of your context:

kubectl config set-context --current --namespace=my-namespace

Set a resource quota. Save this as quota.yaml:

apiVersion: v1
kind: ResourceQuota
metadata:
  name: compute-quota
  namespace: my-namespace
spec:
  hard:
    requests.cpu: "2"
    requests.memory: 4Gi
    limits.cpu: "4"
    limits.memory: 8Gi
    pods: "10"

kubectl apply -f quota.yaml

Quick recap

• kubectl create namespace name makes a namespace.
• Use -n name or set-context to work inside it.
• Add quotas to keep one project from using everything.