WildFly Java Microservice - PART 2: Kubernetes

Table of Contents

Prerequisites
Image Registry
- Quay.io
Kubernetes
What’s next?
References

In this guide, you will learn HOW-TO run the Docker Image you built in WildFly Java Microservice - PART 1: Container Image on Kubernetes.

Prerequisites

To complete this guide, you need:

Complete WildFly Java Microservice - PART 1: Container Image
A Kubernetes cluster: throughout this mini-series, we will use Minikube

Image Registry

To make the my-jaxrs-app:latest Docker Image available to Kubernetes, you need to push it to some Image Registry that is accessible by the Kubernetes cluster you want to use.

Quay.io

There are many Image Registries you can use: in this guide, we will push the my-jaxrs-app:latest Docker Image, to the quay.io Image Registry.

Create a public repository named my-jaxrs-app on quay.io (e.g. https://quay.io/repository/tborgato/my-jaxrs-app).

Note	replace `tborgato` with the name of your account in all the commands that will follow

Tag the Docker image:

podman tag my-jaxrs-app quay.io/tborgato/my-jaxrs-app

Push the my-jaxrs-app Docker Image to it:

podman push quay.io/tborgato/my-jaxrs-app

At this point, the my-jaxrs-app:latest Docker Image should be publicly available and free to be consumed by any Kubernetes Cluster; you can verify this by running:

podman pull quay.io/tborgato/my-jaxrs-app

Note	You can use `wildfly-maven-plugin` to automate the image push to an image registry

Kubernetes

Minikube

You can use whatever Kubernetes cluster you have available; in this guide, and in the following, we will use minikube.

In case you are using minikube, start the cluster:

minikube start

Deploy to Kubernetes

To deploy our quay.io/tborgato/my-jaxrs-app Docker image to Kubernetes, create a file named deployment-my-jaxrs-app.yaml (see kubernetes deployment) in the same directory as the Dockerfile and the pom.xml file, with the following content:

deployment-my-jaxrs-app.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-jaxrs-app-deployment
  labels:
    app: my-jaxrs-app
spec:
  replicas: 1
  selector:
    matchLabels:
      app: my-jaxrs-app
  template:
    metadata:
      labels:
        app: my-jaxrs-app
    spec:
      containers:
      - name: my-jaxrs-app
        image: quay.io/tborgato/my-jaxrs-app
        ports:
        - containerPort: 8080
        - containerPort: 9990
        livenessProbe:
          httpGet:
            path: /health/live
            port: 9990
        readinessProbe:
          httpGet:
            path: /health/ready
            port: 9990
        startupProbe:
          httpGet:
            path: /health/started
            port: 9990

Deploy to your Kubernetes Cluster:

$ kubectl apply -f deployment-my-jaxrs-app.yaml
deployment.apps/my-jaxrs-app-deployment created

We used minikube as Kubernetes Cluster, hence we expose the deployment as NodePort:

$ kubectl expose deployment.apps/my-jaxrs-app-deployment --type=NodePort --port=8080
service/my-jaxrs-app-deployment exposed

Note	you can also use Helm Chart for WildFly to deploy your application

Check your application

Find out on what IP address/port, minikube is exposing your service:

$ minikube service my-jaxrs-app-deployment --url
http://192.168.39.139:30782

Verify it’s working as expected:

$ curl http://192.168.39.139:30782/hello/pippo
Hello 'pippo'.

What’s next?

References

Source code for this guide: https://github.com/wildfly-extras/guides/tree/main/get-started-microservices-on-kubernetes/simple-microservice

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