build simple nginx application on K3s Cluster

After we learn how to build and create k3s cluster on this article, we will try to build simple nginx application on K3s cluster with Let’s Encrypt for the SSL provider.

• install the cert-manager

kubectl create namespace cert-manager
kubectl apply --validate=false -f https://github.com/jetstack/cert-manager/releases/download/v1.0.4/cert-manager.yaml

• create cluster issuer for Let’s Encrypt

apiVersion: cert-manager.io/v1
kind: ClusterIssuer
metadata:
  name: letsencrypt-prod
spec:
  acme:
    server: https://acme-v02.api.letsencrypt.org/directory
    email: [email protected]
    privateKeySecretRef:
      name: letsencrypt-prod
    solvers:
    - http01:
        ingress:
          class: nginx

• Apply the issuer

kubectl apply -f issuer.yaml

• Create a deployment for Nginx

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.19
        ports:
        - containerPort: 80
        - containerPort: 443

• Apply the deployment

kubectl apply -f deployment.yaml

• Create a service to expose the Nginx deployment

apiVersion: v1
kind: Service
metadata:
  name: nginx-service
spec:
  selector:
    app: nginx
  ports:
  - name: http
    port: 80
    targetPort: 80
  - name: https
    port: 443
    targetPort: 443
  type: ClusterIP

• Apply the service

kubectl apply -f service.yaml

• Create an ingress resource to route traffic to the Nginx service

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: nginx-ingress
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
    cert-manager.io/cluster-issuer: letsencrypt-prod
    nginx.ingress.kubernetes.io/force-ssl-redirect: "true"
spec:
  tls:
  - hosts:
    - settingserver.com
    secretName: settingserver-com-tls
  rules:
  - host: settingserver.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: nginx-service
            port:
              name: https

• Apply the ingress

kubectl apply -f ingress.yaml

• Verify the deployment, service, and ingress

kubectl get deployments
kubectl get services
kubectl get ingresses

These are the basic steps to build a simple Nginx application with HTTPS on a K3s cluster. You need to replace the placeholder values with your own certificates and domain name. Additionally, you may need to configure the firewall rules and DNS settings to allow external traffic to reach the ingress controller.