A Step-by-Step Guide to Implementing Horizontal Pod Autoscaler for Nginx on Kubernetes

A Step-by-Step Guide to Implementing Horizontal Pod Autoscaler for Nginx on Kubernetes

To create a Kubernetes configuration file that includes both a deployment of an Nginx server and a Horizontal Pod Autoscaler (HPA), you can define the necessary resources (CPU and memory) and set limits within the YAML file. Below, I'll provide an example of such a YAML file, named nginx-hpa.yaml. This example will set up a basic Nginx deployment and configure HPA to automatically scale the number of pods based on CPU utilization.

Contents of nginx-hpa.yaml:

vi nginx-hpa.yaml

apiVersion: apps/v1

kind: Deployment

metadata:

  name: nginx-deployment

  labels:

    app: nginx

spec:

  replicas: 2

  selector:

    matchLabels:

      app: nginx

  template:

    metadata:

      labels:

        app: nginx

    spec:

      containers:

      - name: nginx

        image: nginx:latest

        ports:

        - containerPort: 80

        resources:

          requests:

            cpu: "100m"  # Minimum necessary CPU to run

            memory: "128Mi"  # Minimum necessary memory to run

          limits:

            cpu: "200m"  # Maximum CPU allowed to use

            memory: "256Mi"  # Maximum memory allowed to use

---

apiVersion: autoscaling/v1

kind: HorizontalPodAutoscaler

metadata:

  name: nginx-hpa

spec:

  scaleTargetRef:

    apiVersion: apps/v1

    kind: Deployment

    name: nginx-deployment

  minReplicas: 1

  maxReplicas: 5

  targetCPUUtilizationPercentage: 50

Breakdown of the nginx-hpa.yaml:

1. Deployment Section:

   • API Version and Kind: Specifies the resource type (Deployment).
   • Metadata: Defines the name and labels used to identify the deployment.
   • Spec:
     • Replicas: Sets the initial number of pods to 2.
     • Selector and Template Labels: Ensures the deployment manages pods labeled as app: nginx.
     • Containers:
       • Name and Image: Uses the latest official Nginx image from Docker Hub.
       • Ports: Exposes port 80 on the container.
       • Resources:
         • Requests: The minimum resources necessary for running each pod.
         • Limits: The maximum resources each pod is allowed to use.

2. Horizontal Pod Autoscaler (HPA) Section:

   • API Version and Kind: Specifies the resource type (HorizontalPodAutoscaler).
   • Metadata: Names the HPA (nginx-hpa).
   • Spec:
     • scaleTargetRef: Points the HPA to the Nginx deployment.
     • minReplicas and maxReplicas: Sets the minimum and maximum number of pods.
     • targetCPUUtilizationPercentage: The target CPU utilization percentage that triggers scaling.

How to Use:

1. Save the file: Copy the contents above into a file named nginx-hpa.yaml.
2. Deploy to Kubernetes:

kubectl apply -f nginx-hpa.yaml

Verify Deployment and HPA:

• Check deployment:

kubectl get deployment nginx-deployment

Check HPA:

kubectl get hpa nginx-hpa

This setup will provide an automatically scaling Nginx server deployment that adjusts the number of pods based on the CPU usage, ensuring efficient resource use based on load.