Overview:

In this lesson, you will learn how to deploy a simple application to Kubernetes using a Deployment and expose it with a Service.

Steps to Deploy an Application:

1. Create a Deployment:

   • A Deployment ensures that a specified number of replicas of an application are running at all times.

   Example Deployment YAML manifest:

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

2. Apply the Deployment:

   kubectl apply -f deployment.yaml

3. Verify Pods Are Running:

   kubectl get pods

4. Expose the Deployment:

   • Use a Service to make the application accessible.

   Example Service YAML manifest:

   apiVersion: v1
   kind: Service
   metadata:
     name: my-app-service
   spec:
     selector:
       app: my-app
     ports:
     - protocol: TCP
       port: 80
       targetPort: 80
     type: NodePort

5. Apply the Service:

   kubectl apply -f service.yaml

6. Access the Application:

   • Retrieve the NodePort assigned to your Service:

     kubectl get service my-app-service

   • Access the application using http://<NodeIP>:<NodePort>.

Activity:

Deploy the Nginx application using the provided Deployment and Service YAML files. Verify it by accessing the application in your web browser.