Overview:

Horizontal Pod Autoscaling (HPA) automatically adjusts the number of Pods in a deployment based on resource utilization or custom metrics.

Key Concepts:

1. HPA Metrics:

   • CPU utilization

   • Memory usage

   • Custom metrics (via Prometheus Adapter)

2. HPA Workflow:

   • Monitor metrics

   • Trigger scaling events

Steps to Enable HPA:

1. Ensure Metrics Server is Installed:

   kubectl get deployment metrics-server -n kube-system

2. Create a Deployment:

   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: nginx-deployment
   spec:
     replicas: 2
     selector:
       matchLabels:
         app: nginx
     template:
       metadata:
         labels:
           app: nginx
       spec:
         containers:
         - name: nginx
           image: nginx
           resources:
             requests:
               cpu: "200m"
               memory: "200Mi"
             limits:
               cpu: "500m"
               memory: "500Mi"

   kubectl apply -f nginx-deployment.yaml

3. Create an HPA Resource:

   kubectl autoscale deployment nginx-deployment --cpu-percent=50 --min=1 --max=5

4. View HPA Status:

   kubectl get hpa

Activity:

Deploy an application and configure HPA to automatically scale Pods based on CPU usage.