Tutorial: Publish a Quarkus application in Kubernetes, Minikube and Dockerhub

https://www.flickr.com/photos/marcus-paulo/4148555853/

Notes

This is my first English post, then please give me your feedback, and suggestion to correct any mistakes.

Introduction

The article purpose to create a simple application in Quakus and publish in Minikube (Kubernetes for the local test) and finally publish the image Docker to in Dockerhub.

For more information on these technologies: Kubernetes (K8S), Docker, Minikube, Kubectl e do Quarkus, please visit these sites:

Docker: https://www.docker.com/

Kubernetes: https://kubernetes.io/pt/

Minikube: https://minikube.sigs.k8s.io/docs/start/

Minikube (Kubernetes): https://kubernetes.io/pt/docs/tutorials/kubernetes-basics/create-cluster/cluster-intro/

Quarkus: https://quarkus.io/

Minikube is local Kubernetes, focusing on making it easy to learn and develop for Kubernetes. It is not recommending to production environment.

Prerequisites

• Install Docker: https://docs.docker.com/engine/install/
• Install Kubernetes: https://kubernetes.io/pt/docs/setup/
• Install Kubeclt: https://kubernetes.io/docs/tasks/tools/
• Install Minikube: https://minikube.sigs.k8s.io/docs/start/
• Install Open JDK 11+: https://openjdk.java.net/install/

Let’s go! We will create a new simple Quarkus application.

Create a simple Quarkus application by command line

mvn io.quarkus:quarkus-maven-plugin:1.13.0.Final:create \\\\
    -DprojectGroupId=br.com.mp \\\\
    -DprojectArtifactId=kubernetes-quarkus \\\\
    -DclassName="br.com.mp.kubernetes.quarkus.rest.GreetingResource" \\\\
    -Dpath="/hello" \\\\
    -Dextensions="resteasy,kubernetes,jib"

Access the project folder

cd kubernetes-quarkus

In the next step, let’s go to test the project

mvn quarkus:dev

Result in terminal (console)

Running Quarkus application by command line

mvn quarkus:add-extension -Dextensions="quarkus-minikube"

Or you can insert in pom.xml

<dependency>
  <groupId>io.quarkus</groupId>
  <artifactId>quarkus-minikube</artifactId>
</dependency>

It is possible to create Quarkus application by command line, adding Minikube extensions.

Creating a local Container Registry in Minikube

It is necessary to set the environment variable with “eval” command.

eval $(minikube -p minikube docker-env)

Create Docker image with Quarkus by command line

Next step, create a maven package with Quarkus parameter to build a container image.

mvn package -Dquarkus.container-image.build=true

Kubernetes and Minikube manifest create

After execute the last command, maven and Quarkus will create the manifest files, located in the folder “/target/kubernetes”, as you see in the image below.

List of all docker images

//List all docker images
docker image ls
[output]
REPOSITORY                        TAG              IMAGE ID       CREATED         SIZE
marcus/kubernetes-quarkus-teste   1.0.0-SNAPSHOT   e574987218c4   3 minutes ago   199MB

In the next step, we need to apply Minikube manifest to publish in Minikube Kubernetes

kubectl apply -f target/kubernetes/minikube.yml
[output]
service/kubernetes-quarkus-teste created
deployment.apps/kubernetes-quarkus-teste created

After a few seconds or minutes, the application is available on Minikube,

Pods are the smallest, most basic deployable objects in Kubernetes (https://cloud.google.com/kubernetes-engine/docs/concepts/pod)

List of all pods

kubectl get po
[output]
NAME                                        READY   STATUS    RESTARTS   AGE
kubernetes-quarkus-teste-54db4f8df8-gf7nf   1/1     Running   0          6m52s

Access the application at the local machine

To access on the local machine, it is required to redirect Minikube address to localhost, type this command. (Each Pod there is a unique name)

kubectl port-forward pod/kubernetes-quarkus-teste-54db4f8df8-gf7nf 8080:8080
[output]
Forwarding from 127.0.0.1:8080 -> 8080
Forwarding from [::1]:8080 -> 8080
Handling connection for 8080

Access application in browser

Open your browser and insert this address:http://localhost:8080

Publish the image to Dockerhub

From now, we are sending our docker image to Dockerhub, with maven command and Quarkus parameter (container image).

mvn clean package -Dquarkus.container-image.push=true

In my case, it happened this error

Caused by: com.google.cloud.tools.jib.api.RegistryUnauthorizedException:Unauthorized for registry-1.docker.io/marcus/kubernetes-quarkus-teste
[ERROR]         at com.google.cloud.tools.jib.registry.RegistryEndpointCaller.call(RegistryEndpointCaller.java:164)
[ERROR]

For fix this problem, please follow these steps:

1 — Type this command to login on Dockerhub services

docker login

2 — The local Docker image was created with username machine, in my case is marcus/kubernetes-quarkus, but the correct Dockerhub username is marcuspaulo.

Inside the Quarkus project, search application.properties file and insert the line above (with your Dockerhub username)

quarkus.container-image.group=marcuspaulo

Publish in the Dockerhub

mvn clean package -Dquarkus.container-image.push=true

Now, open your browser and access this address: https://hub.docker.com/repositories

I hope that you enjoy this tutorial. Thanks for your attention. Please like and share this post. See you soon.

Source code

https://github.com/marcuspaulo/kubernetes-quarkus

References

https://quarkus.io/guides/container-image#quarkus-container-image_quarkus.container-image.registry

https://quarkus.io/guides/deploying-to-kubernetes

https://quarkus.io/guides/kubernetes-client

https://minikube.sigs.k8s.io/docs/handbook/registry/

https://haralduebele.blog/2020/04/03/deploy-your-quarkus-applications-on-kubernetes-almost-automatically/

https://cloud.google.com/kubernetes-engine/docs/concepts/pod