Step 1: Ensure Metrics Server is Running
Since HPA relies on the Metrics Server, ensure it's running:
kubectl get deployment -n kube-system metrics-server
If it's not installed, install it:
kubectl apply -f https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml
Check if Metrics Server is collecting data:
kubectl top nodes
kubectl top pods
Step 2: Configure HPA for the Nginx Deployment
Create an HPA (Horizontal Pod Autoscaler) YAML file:
apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
name: nginx-hpa
spec:
scaleTargetRef:
apiVersion: apps/v1
kind: Deployment
name: nginx-deployment
minReplicas: 1
maxReplicas: 5
metrics:
- type: Resource
resource:
name: cpu
target:
type: Utilization
averageUtilization: 50
Apply the HPA:
kubectl apply -f nginx-hpa.yaml
Verify the HPA is created:
kubectl get hpa
Step 3: Generate Load on Nginx Deployment
To test autoscaling, generate a CPU load.
Method 1: Using a Load Generator Pod
Run a temporary busybox pod and send HTTP requests in a loop:
kubectl run -it --rm load-generator --image=busybox -- /bin/sh
Inside the pod, run:
while true; do wget -q -O- http://nginx-service.default.svc.cluster.local; done
Exit the pod using Ctrl+C.
Method 2: Using Apache Benchmark (ab)
Install ab on your local machine or inside a pod, then run:
ab -n 100000 -c 100 http://nginx.local/
This sends 100,000 requests with 100 concurrent users.
Step 4: Monitor HPA Scaling
Check HPA scaling events:
kubectl get hpa
Check running pods to see if replicas increased:
kubectl get pods -l app=nginx
Once load decreases, replicas should scale down automatically.
Step 5: Cleanup (Optional)
If you want to remove HPA and stop scaling:
kubectl delete hpa nginx-hpa
Now your Nginx deployment will automatically scale based on CPU usage! 🚀