NameSpace

A Linux NameSpace implements kernel-level resource isolation
A namespace in Kubernetes is a logical partition inside a cluster. Think of it like a virtual cluster within your actual cluster. It helps you organize, isolate, and manage resources.
Kubernetes offers NameSpace resources that provide the same functionality
Different NameSpaces can be used to strictly separate between customer resources
NameSpaces are used to apply different security-related settings -Role-Based Access Control (RBAC)
Separate environments (e.g., dev, test, prod)
Isolate teams or projects
The shortend command can be used is ns instead of namespace

Using NameSpace

Command	Description
`kubectl create namespace <namespace_name>`	Creates a new Kubernetes namespace (e.g., `mynamespace`).
`kubectl ... -n <namespace_name>`	Runs a command in a specific namespace by specifying the `-n` flag followed by the namespace name.
`kubectl get namespace`	Lists all the available namespaces in the cluster.
`kubectl get ... all --all-namespaces`	Retrieves all resources across all namespaces using the `--all-namespaces` or `-A` flag.

Demo: Using NameSpace

myNameSpace.yml


apiVersion: v1
kind: Pod
metadata:
  labels:
    run: nginx
  name: nginx
  namespace: secret
spec:
  containers:
    - image: nginx
      name: nginx

Create namespace with a custom name


kubectl create ns secret

Output


controlplane $ kubectl create ns secret
namespace/secret created

Create the Pod


kubectl create -f myNameSpace.yml

Output


controlplane $ kubectl apply -f myNameSpace.yaml
pod/mynginx created

List all the running Pods


kubectl get pods

Output


controlplane $ kubectl get pods
NAME        READY   STATUS     RESTARTS   AGE
init-demo   0/1     Init:0/1   0          12m

You don’t see your pod running that’s beacuse it’s running in a different namespace, and by default the kubectl get pods display the running pods in default namespace. To view the pods from a specific namespace -


kubectl get pods -n secret

Output


controlplane $ kubectl get pods -n secret
NAME      READY   STATUS    RESTARTS   AGE
mynginx   1/1     Running   0          18s