Kubernetes Native Quarkus

This application demonstrates how to create a Quarkus application that retrieves messages from a Kafka topic ("power") and inserts the events into a database.

Watch a live demo from the Jfokus conference here: https://youtu.be/haulxnEtjUc?si=D_gpALKS75UVR65V

It features:

• a DevicePower class that represents the database entity
• a KafkaResource class that shows how to retrieve messages from a Kafka topic
• a PowerResource class that returns the values from the database table

You can run this demo on your local machine with Quarkus Dev Mode (see below) which will spin up a Kafka and PostgreSQL testcontainer. The application.properties file shows how to set limits, requests, secrets and configmaps for your kubernetes environment.

Deploying to Kubernetes

If you need a Kubernetes cloud environment to test with, you can get a free Openshift Developer sandbox at https://developers.redhat.com/sandbox.

You will have to create the configmap and secret before deploying the application. Examples can be found in the src/main/kube folder. You will also need to create a postgresql database (db 'quarkus') and a Kafka cluster. You can use the kafka.yml and postgresql.yml in the same src/main/kube folder if you want simple ephemeral test instances.

You can apply these files with kubectl apply -f src/main/kube.

Before building & deploying the container image, make sure to update the application.properties to point to your registry:

quarkus.container-image.registry=quay.io
quarkus.container-image.group=kevindubois

Then you can package your app, build it into a container and push to a registry with quarkus image push --also-build And deploy it with quarkus deploy

If you want to learn more about Quarkus, please visit its website: https://quarkus.io/ .

Running the application in dev mode

You can run your application in dev mode that enables live coding using:

./mvnw compile quarkus:dev

NOTE: Quarkus now ships with a Dev UI, which is available in dev mode only at http://localhost:8080/q/dev/.

Packaging and running the application

The application can be packaged using:

./mvnw package

It produces the quarkus-run.jar file in the target/quarkus-app/ directory. Be aware that it’s not an über-jar as the dependencies are copied into the target/quarkus-app/lib/ directory.

The application is now runnable using java -jar target/quarkus-app/quarkus-run.jar.

If you want to build an über-jar, execute the following command:

./mvnw package -Dquarkus.package.type=uber-jar

The application, packaged as an über-jar, is now runnable using java -jar target/*-runner.jar.

Creating a native executable

You can create a native executable using:

./mvnw package -Dnative

Or, if you don't have GraalVM installed, you can run the native executable build in a container using:

./mvnw package -Dnative -Dquarkus.native.container-build=true

You can then execute your native executable with: ./target/kubenative-1.0.0-SNAPSHOT-runner

If you want to learn more about building native executables, please consult https://quarkus.io/guides/maven-tooling.