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Lab 4.4 - LoadBalancer and Cloud Integration

Lab Objectives​

By the end of this lab, you will be able to:

  • Understand the LoadBalancer Service type.
  • Configure a LoadBalancer Service.
  • Understand integration with cloud load balancers.
  • Test external access via LoadBalancer.

Estimated Duration​

30-45 minutes

Prerequisites​

  • kubectl installed and configured.
  • Functional local Kubernetes cluster (minikube or kind).
  • Knowledge of Services (Chapters 4.1 and 4.2).

Part 1: Understanding LoadBalancer​

A LoadBalancer Service type exposes the Service externally using a load balancer provided by the cloud provider (AWS ELB, Azure Load Balancer, GCP Load Balancer).

On a local cluster (minikube/kind), the LoadBalancer behaves like a NodePort, but in cloud production, it automatically provisions an external load balancer.

Part 2: Creating a LoadBalancer Service​

Step 2.1: Deploy an Application​

Create a simple Deployment:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-app
spec:
  replicas: 3
  selector:
    matchLabels:
      app: web-app
  template:
    metadata:
      labels:
        app: web-app
    spec:
      containers:
      - name: nginx
        image: nginx:1.20
        ports:
        - containerPort: 80

Apply:

kubectl apply -f deployment.yaml

Step 2.2: Create a LoadBalancer Service​

Create service-loadbalancer.yaml:

apiVersion: v1
kind: Service
metadata:
  name: web-app-lb
spec:
  type: LoadBalancer
  selector:
    app: web-app
  ports:
  - port: 80
    targetPort: 80
    protocol: TCP

Apply:

kubectl apply -f service-loadbalancer.yaml

Part 3: Verification​

Step 3.1: Verify the Service​

kubectl get svc web-app-lb

On minikube, you will see <pending> for the EXTERNAL-IP. Enable the tunnel:

minikube tunnel

In another terminal, check again:

kubectl get svc web-app-lb

You should see an EXTERNAL-IP.

Step 3.2: Test Access​

Test the access:

curl http://<EXTERNAL-IP>

Part 4: Cloud Integration (Conceptual)​

On a cloud cluster (AWS, Azure, GCP), the LoadBalancer automatically provisions:

  • AWS: Elastic Load Balancer (ELB)
  • Azure: Azure Load Balancer
  • GCP: Google Cloud Load Balancer

The cloud provider automatically handles the creation and configuration of the load balancer.

Part 5: Cleanup​

kubectl delete svc web-app-lb
kubectl delete deployment web-app

Lab Summary​

In this lab, you created a LoadBalancer Service and understood how it works. On a cloud cluster, this Service type automatically provisions an external load balancer to expose your application.

Next Steps​

This module on Services and Networking is now complete. You can move on to Module 5 on Configuration and Secrets.

Module 5: Configuration and Secrets

Lab created: December 2024