Creating custom namespaces in Kubernetes - Step-by-Step CLI Walkthrough

Introduction

When you run many applications in Kubernetes, they can get mixed up and hard to manage. Creating custom namespaces helps keep your apps organized by grouping related resources together.

When you want to separate development and production environments in the same cluster.

When multiple teams share the same Kubernetes cluster and need isolated spaces.

When you want to apply different access controls to different groups of resources.

When you want to limit resource usage for a specific group of applications.

When you want to organize resources by project or application type.

Config File - namespace.yaml

namespace.yaml

apiVersion: v1
kind: Namespace
metadata:
  name: example-namespace

This file defines a new namespace named example-namespace. The apiVersion and kind tell Kubernetes what type of object this is. The metadata.name sets the namespace's name.

Commands

This command creates the custom namespace defined in the namespace.yaml file. It tells Kubernetes to add this new isolated space.

Terminal

kubectl apply -f namespace.yaml

Expected Output

namespace/example-namespace created

This command lists all namespaces in the cluster so you can verify your new namespace was created.

Terminal

kubectl get namespaces

Expected Output

NAME              STATUS   AGE

default           Active   10d

kube-system       Active   10d

example-namespace  Active   1m

This command sets your current kubectl context to use the new namespace by default, so you don't have to specify it in every command.

Terminal

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

Expected Output

Context "your-cluster-context" modified.

This command lists pods in the current namespace, which is now example-namespace. It helps confirm you are working inside the right namespace.

Terminal

kubectl get pods

Expected Output

No resources found in example-namespace namespace.

Key Concept

If you remember nothing else from this pattern, remember: namespaces create isolated spaces in Kubernetes to organize and separate resources.

Common Mistakes

Not creating a namespace before trying to deploy resources into it.

Kubernetes will fail to find the namespace and the deployment will not work.

Always create the namespace first using a YAML file or kubectl before deploying resources there.

Forgetting to switch the kubectl context to the new namespace.

kubectl commands will run in the default namespace, causing confusion or resource deployment in the wrong place.

Use 'kubectl config set-context --current --namespace=your-namespace' to switch namespaces.

Summary

Create a namespace YAML file to define a new isolated space.

Apply the YAML file with kubectl to create the namespace.

List namespaces to verify creation.

Set your kubectl context to the new namespace for easier management.