Namespace & Practical

What is a Namespace?

In Kubernetes, namespaces provide a mechanism for isolating groups of resources within a single cluster. You can think of a namespace as a virtual cluster built on top of the same physical cluster.

Namespaces are intended for use in environments with many users spread across multiple teams, or projects. Resources like Pods, Services, and Deployments are created within a specific namespace. If no namespace is specified, they are placed in the default namespace.

Why use Namespaces?

Namespaces are important to use because they help solve several problems:

If we do kubectl get pods then all pods will come up, but if you are a backend developer then other than backend pods all pods are irrelevant to you.
For security purposes, you can configure RBAC (Role-Based Access Control) to allow a backend developer to access ONLY backend pods.

Creating a new namespace

Create a new namespace
Terminal
bash
```
kubectl create namespace backend-team
```
Get all the namespaces
Terminal
bash
```
kubectl get namespaces
```
Get all pods in the namespace
Terminal
bash
```
kubectl get pods -n my-namespace
```

Create the manifest for a deployment in the namespace

yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  namespace: backend-team
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:latest
        ports:
        - containerPort: 80

Apply the manifest
Terminal
bash
```
kubectl apply -f deployment-ns.yml
```
Get the deployments in the namespace
Terminal
bash
```
kubectl get deployment -n backend-team
```
Get the pods in the namespace
Terminal
bash
```
kubectl get pods -n backend-team
```

Set the default context to be the namespace

Terminal

bash

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

Try seeing the pods now
Terminal
bash
```
kubectl get pods
```

Revert back the kubectl config

Terminal

bash

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