Kubernetes Namespaces

-

 In Kubernetes, Namespaces provide a logical way to isolate and organize groups of resources within a single cluster. They are especially useful in environments where multiple teams or projects share the same cluster, allowing separation and management of resources independently.

Each resource in a Namespace must have a unique name, but resources across different Namespaces can share the same name without conflict.

Default Kubernetes Namespaces

When you create a Kubernetes cluster, it comes with four built-in Namespaces:

  1. default

  2. kube-node-lease

  3. kube-public

  4. kube-system

To view all available Namespaces, use:

kubectl get namespaces

You’ll see the four default Namespaces listed.

Bonus: Kubernetes Dashboard Namespace (Minikube Specific)

When you install Minikube, an additional Namespace called kubernetes-dashboard is automatically created.
This Namespace is specific to Minikube and not present in standard Kubernetes clusters.

1. kube-system

The kube-system Namespace contains core system components and processes managed by Kubernetes itself.
It includes system-level Pods like:

  • kube-dns

  • kube-proxy

  • etcd

  • kube-apiserver

This Namespace is not meant for user-created workloads. Developers should avoid creating or modifying resources in kube-system.

2. kube-public

The kube-public Namespace holds publicly accessible cluster information.
It contains a ConfigMap that stores details about the cluster, which can be accessed even without authentication.

To view this information:

kubectl cluster-info

This command retrieves data stored in the kube-public Namespace.

3. kube-node-lease

The kube-node-lease Namespace was introduced to improve cluster performance and scalability.
It maintains Node lease objects, which record the heartbeat and availability status of each Node.

Each Node has its own lease object, helping the Kubernetes control plane efficiently detect Node failures.

4. default

The default Namespace is where Kubernetes places all resources if no Namespace is explicitly specified.
When you create a Pod, Service, or ConfigMap without assigning a Namespace, it’s automatically placed in default.

Creating Namespaces

You can create new Namespaces in two ways:

1. Using CLI Commands

Run the following command to create a Namespace named my-ns:

kubectl create namespace my-ns

To verify:

kubectl get namespaces

You’ll see my-ns listed among the available Namespaces.

2. Using a Configuration File

It’s often better to define Namespaces using a YAML configuration file — this provides version control and traceability within your infrastructure code.

Example:

apiVersion: v1
kind: Namespace
metadata:
  name: development
  labels:
    name: development

Apply the file:

kubectl create -f namespace.yaml

Creating Components in the Default Namespace

When no Namespace is specified, Kubernetes automatically creates resources in the default Namespace.

Example ConfigMap:

apiVersion: v1
kind: ConfigMap
metadata:
  name: my-configmap
data:
  db_url: my-service.database

Apply the ConfigMap:

kubectl apply -f my-config-map.yaml

To verify which Namespace it belongs to:

kubectl get configmap -n default

Or to view detailed YAML output:

kubectl get configmap my-configmap -n default -o yaml

You’ll see that the Namespace field is set to default.

Creating Components in a Custom Namespace

You can assign resources to a specific Namespace in two ways:

1. Specifying Namespace via CLI

Add the --namespace flag when applying the resource file:

kubectl apply -f my-config-map.yaml --namespace=my-ns

Make sure the Namespace (my-ns) already exists, or you’ll get an error.

2. Specifying Namespace in the YAML File

Include the Namespace directly in the metadata section:

apiVersion: v1
kind: ConfigMap
metadata:
  name: my-configmap
  namespace: my-ns
data:
  db_url: my-service.database

Apply the file:

kubectl apply -f my-config-map.yaml

Then verify:

kubectl get configmap -n my-ns -o yaml

The output will confirm that the ConfigMap now belongs to the my-ns Namespace.

Changing the Active Namespace

By default, your active Namespace is default.
To easily switch between Namespaces, use the kubens tool from kubectx.

Install kubectx and kubens

sudo snap install kubectx --classic

View All Namespaces

kubens

The active Namespace will appear highlighted in green.

Switch to Another Namespace

kubens my-ns

Now, your active Namespace is set to my-ns, meaning any subsequent resource creation (without specifying a Namespace) will default to this Namespace.

Conclusion

Kubernetes Namespaces are essential for managing complex, multi-team, or multi-project environments within a single cluster.
They offer logical separation, resource isolation, and simplified access control — making them a fundamental part of any production-grade Kubernetes architecture.

Comments

Post a Comment

Popular posts from this blog

Cloud Computing Tutorial

-
Cloud computing is a technology that allows individuals and organizations to create, configure, and manage applications over the internet. It encompasses computing platforms, storage, software, and databases, offering flexibility and scalability without the need for direct hardware management. This tutorial covers the fundamentals of cloud computing, including service and deployment models, infrastructure, virtualization, and advanced concepts for a deeper understanding of cloud technologies. What is Cloud Computing? Cloud computing refers to the delivery of computing services—such as storage, servers, databases, networking, and software—over the internet. It allows users to access and process data remotely without investing in physical infrastructure. Cloud computing provides: Scalability:  Easily adjust computing resources based on demand. Flexibility:  Access services from anywhere at any time. Cost-effectiveness:  Pay only for the resources you use. Security:  Pr...
Read more

History of Cloud Computing

-
 Have you ever wondered how cloud computing began? Who first came up with the idea, and how did it evolve into the services we use every day, like Netflix, Google Drive, and Amazon Web Services (AWS)? Today, using computers, storage, and applications from anywhere in the world is easy. We don’t need to buy expensive equipment or set up complex systems. But a few decades ago, this concept was completely new and revolutionary. Imagine it’s the 1990s and you want to store 1,000 photos—you would have needed a large hard drive and the technical know-how to set it up at home. Today, with services like Google Drive, you can simply upload your photos online and access them anytime, anywhere, without buying additional hardware. This convenience is the essence of cloud computing, and in this article, we will explore its history, development, and impact. What is Cloud Computing? Cloud computing refers to the delivery of computing services—including storage, databases, servers, networking,...
Read more

Mastering Kubernetes Deployment Strategies: The Real-World Guide for DevOps, Cloud, and SRE Engineers

-
 In today’s rapidly evolving DevOps landscape, Kubernetes has become the engine powering modern, scalable infrastructure. Whether you’re preparing for a DevOps, Cloud Engineer, or SRE interview , or managing large-scale systems in production, understanding Kubernetes deployment strategies is a must-have skill. Because here’s the truth: In production environments, simply replacing containers is a recipe for disaster. It can trigger service downtime , bug exposure , or even complete outages — all of which can damage customer trust and brand reputation. That’s why seasoned engineers rely on well-defined deployment strategies — controlled, testable, and reversible methods to roll out new versions safely. Why Deployment Strategies Matter A deployment strategy defines how new application versions are released and how they interact with existing versions during the rollout. In DevOps and Kubernetes contexts, the right deployment approach ensures: 🔹 Minimal downtime and c...
Read more