expressjsHow can I deploy an Express.js application on Kubernetes?

1. Create a Dockerfile that builds a Docker image for your Express.js application.

FROM node:10

RUN mkdir -p /usr/src/app
WORKDIR /usr/src/app

COPY package*.json ./

RUN npm install

COPY . .

EXPOSE 3000

CMD ["npm", "start"]

2. Build the Docker image and push it to a Docker registry.

docker build -t express-app .
docker tag express-app:latest <docker-registry>/express-app:latest
docker push <docker-registry>/express-app:latest

3. Create a Kubernetes deployment manifest file.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: express-app
spec:
  replicas: 1
  selector:
    matchLabels:
      app: express-app
  template:
    metadata:
      labels:
        app: express-app
    spec:
      containers:
        - name: express-app
          image: <docker-registry>/express-app:latest
          ports:
            - containerPort: 3000

4. Create a Kubernetes service manifest file.

apiVersion: v1
kind: Service
metadata:
  name: express-app
spec:
  type: NodePort
  selector:
    app: express-app
  ports:
    - protocol: TCP
      port: 3000
      targetPort: 3000

5. Deploy the application to Kubernetes.

kubectl apply -f deployment.yaml
kubectl apply -f service.yaml

6. Verify the deployment.

kubectl get pods

Output example

NAME                              READY   STATUS    RESTARTS   AGE
express-app-7c8d7b6f9-x2lhb       1/1     Running   0          3m

7. Access the application.

The application will be accessible at <node-ip>:<node-port>.

Helpful links

• Dockerfile reference
• Kubernetes deployment manifest reference
• Kubernetes service manifest reference
• Kubernetes get pods reference

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