NameSpace

A Linux NameSpace implements kernel-level resource isolation
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)
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

Job Manifest Cheatsheet