Compare the application logs before and after you exposed it as a Service.

Try to open the app several times while the proxy into the Service is running.

What do you see in the logs? Does the number of logs increase each time you open the app?

When the application is exposed as a service, it will show the logs whenever the application is accessed with GET.

Notice that there are two versions of kubectl get invocation during this tutorial section.

The first does not have any option, while the latter has -n option with value set to kube-system.

What is the purpose of the -n option and why did the output not list the pods/services that you explicitly created?

The option n is used to determine namespace in Kubernetes cluster, which is used to allocate and organize resources in a cluster.

What is the difference between Rolling Update and Recreate deployment strategy?

Rolling Update is a deployment strategy where the application is updated incrementally without any downtime, while recreate is a deployment strategy where the application is updated by stopping the old version and then starting the new version.

Try deploying the Spring Petclinic REST using Recreate deployment strategy and document your attempt.

1. Starting

2. Creating deployment yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: spring-petclinic-rest
  labels:
    app: spring-petclinic
spec:
  replicas: 1
  strategy:
    type: Recreate
  selector:
    matchLabels:
      app: spring-petclinic
  template:
    metadata:
      labels:
        app: spring-petclinic
    spec:
      containers:
      - name: spring-petclinic-rest
        image: springcommunity/spring-petclinic-rest:2.4.2
        ports:
        - containerPort: 9966

3. Apply development

4. Creating service yaml

apiVersion: v1
kind: Service
metadata:
  name: spring-petclinic-rest
spec:
  selector:
    app: spring-petclinic
  ports:
    - protocol: TCP
      port: 80
      targetPort: 9966
  type: LoadBalancer

4. Apply service

5. Running the service

Prepare different manifest files for executing Recreate deployment strategy.

apiVersion: v1
kind: Service
metadata:
  name: spring-petclinic-rest
spec:
  selector:
    app: spring-petclinic
  ports:
    - protocol: TCP
      port: 80
      targetPort: 9966
  type: LoadBalancer

What do you think are the benefits of using Kubernetes manifest files?

Using manifest file makes the development faster, there are version control, they are reproducible, and can be automated.

Recall your experience in deploying the app manually and compare it to your experience when deploying the same app by applying the manifest files (i.e., invoking kubectl apply -f command) to the cluster

I'd prefer to use manifest instead of doing everything manually.