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Exercise 1: Basic Kubernetes Resources

Objective​

Learn to create and manage basic Kubernetes resources: Pods, Deployments, and Services. This is the foundation for everything else you'll do in Kubernetes.

Prerequisites​

  • K3s cluster running
  • kubectl configured and working
  • Basic understanding of containers

Verify your setup:

kubectl get nodes

You should see your cluster nodes listed.

Exercise: Deploy a Simple Web Application​

Step 1: Create a Namespace​

Namespaces help organize your resources. Let's create one for this exercise.

Command:

kubectl create namespace practice-01

YAML Version: Create namespace.yaml:

apiVersion: v1
kind: Namespace
metadata:
  name: practice-01

Apply:

kubectl apply -f namespace.yaml

Verify:

kubectl get namespace practice-01

Step 2: Create a Deployment​

A Deployment manages Pods and ensures they stay running. Let's deploy a simple nginx web server.

Command:

kubectl create deployment hello-world \
  --image=nginx \
  --namespace=practice-01

YAML Version: Create deployment.yaml:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: hello-world
  namespace: practice-01
spec:
  replicas: 1
  selector:
    matchLabels:
      app: hello-world
  template:
    metadata:
      labels:
        app: hello-world
    spec:
      containers:
        - name: nginx
          image: nginx:latest
          ports:
            - containerPort: 80

Apply:

kubectl apply -f deployment.yaml

Verify:

kubectl get deployment hello-world -n practice-01
kubectl get pods -n practice-01

Wait until the pod shows Running status.

Step 3: Expose with a Service​

Services provide a stable way to access your Pods. Let's create a ClusterIP service.

Command:

kubectl expose deployment hello-world \
  --type=ClusterIP \
  --port=80 \
  --namespace=practice-01

YAML Version: Create service.yaml:

apiVersion: v1
kind: Service
metadata:
  name: hello-world
  namespace: practice-01
spec:
  selector:
    app: hello-world
  ports:
    - protocol: TCP
      port: 80
      targetPort: 80
  type: ClusterIP

Apply:

kubectl apply -f service.yaml

Verify:

kubectl get service hello-world -n practice-01

Step 4: Test the Application​

Since ClusterIP services are only accessible within the cluster, we'll use port forwarding to test it.

kubectl port-forward deployment/hello-world 8080:80 -n practice-01

In another terminal, test it:

curl http://localhost:8080

You should see the nginx welcome page HTML. Press Ctrl+C to stop port forwarding.

Verification​

Check that everything is working:

# Check deployment
kubectl get deployment hello-world -n practice-01

# Check pods
kubectl get pods -n practice-01 -l app=hello-world

# Check service
kubectl get service hello-world -n practice-01

# Check service endpoints
kubectl get endpoints hello-world -n practice-01

All resources should show as ready and running.

Understanding What Happened​

  • Namespace: Isolated environment for your resources
  • Deployment: Manages Pod lifecycle, ensures desired number of replicas
  • Pod: The actual container running nginx
  • Service: Provides stable network access to Pods, even if they restart

Cleanup​

Remove all resources:

kubectl delete namespace practice-01

Or delete individual resources:

kubectl delete -f service.yaml
kubectl delete -f deployment.yaml
kubectl delete -f namespace.yaml

Next Steps​

→ Exercise 2: Namespaces and Resources

Additional Practice​

Try these variations:

  1. Scale the deployment to 3 replicas: kubectl scale deployment hello-world --replicas=3 -n practice-01
  2. Check how Kubernetes distributes the Pods: kubectl get pods -n practice-01 -o wide
  3. Delete one Pod and watch it get recreated: kubectl delete pod <pod-name> -n practice-01