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Lab 12.2 - Horizontal and Vertical Autoscaling

Lab Objectives​

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

  • Configure a Horizontal Pod Autoscaler (HPA).
  • Understand how HPA works.
  • Test metrics-based autoscaling.
  • Understand the Vertical Pod Autoscaler (VPA).

Estimated Duration​

60-75 minutes

Prerequisites​

  • kubectl installed and configured.
  • Kubernetes cluster with metrics-server.
  • Knowledge of Deployments.

Part 1: Installing metrics-server​

Step 1.1: Install metrics-server​

kubectl apply -f https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml

Verify:

kubectl get deployment metrics-server -n kube-system

Part 2: Creating an HPA​

Step 2.1: Create a Deployment​

Create deployment-hpa.yaml:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: hpa-app
spec:
  replicas: 2
  selector:
    matchLabels:
      app: hpa-app
  template:
    metadata:
      labels:
        app: hpa-app
    spec:
      containers:
      - name: app
        image: nginx:1.20
        resources:
          requests:
            cpu: 100m
            memory: 128Mi
          limits:
            cpu: 500m
            memory: 256Mi

Apply:

kubectl apply -f deployment-hpa.yaml

Step 2.2: Create an HPA​

Create hpa.yaml:

apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
  name: hpa-app
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: hpa-app
  minReplicas: 2
  maxReplicas: 10
  metrics:
  - type: Resource
    resource:
      name: cpu
      target:
        type: Utilization
        averageUtilization: 50

Apply:

kubectl apply -f hpa.yaml

Part 3: Testing Autoscaling​

Step 3.1: Generate Load​

Create a Pod to generate load:

kubectl run -i --tty load-generator --rm --image=busybox --restart=Never -- /bin/sh -c "while true; do wget -q -O- http://hpa-app-service; done"

Step 3.2: Observe Autoscaling​

Monitor the HPA:

kubectl get hpa hpa-app -w

Monitor the Pods:

kubectl get pods -l app=hpa-app -w

Part 4: VPA (Introduction)​

VPA automatically adjusts Requests and Limits. Installation is more complex and requires an operator.

Lab Summary​

In this lab, you configured horizontal autoscaling with HPA. You tested autoscaling based on CPU usage.

Next Steps​

The next lab will show you how to set up GitOps with ArgoCD.

Lab 12.3: GitOps with ArgoCD

Lab created on: December 2024