These examples show how to connect to a Kafka broker in a Camel K integration.
You can find more information about Apache Camel and Apache Camel K on the official Camel website.
Read the general instructions in the root README.md file for setting up your environment and the Kubernetes cluster before looking at this example.
Make sure you've read the installation instructions for your specific cluster before starting the example.
A Kafka broker: handles the storage and passing of messages.
To use Kafka with authentication, we have a dedicated section to show how to authenticate Camel K to Kafka.
For a simple use case without client authentication, continue with this guide.
To run this example, first set-up Kafka on your k8s cluster. A convenient way to do so is by using the Strimzi project. Visit https://strimzi.io/quickstarts/ for set-up instructions. For the instructions on the linked site, it will suffice to only apply the Strimzi installation file and provision the kafka cluster.
IMPORTANT: The kafka.host value in application.properties needs to be set to the CLUSTER-IP address of the my-cluster-kafka-bootstrap service in the kafka namespace. To do this run:
kafkaip=`kubectl get svc/my-cluster-kafka-bootstrap -n kafka -ojsonpath="{.spec.clusterIP}"`; sed -i "/kafka\.host/s/<.*>/$kafkaip/g" application.properties
Create a configmap to contain the properties:
kubectl create configmap kafka.props --from-file=application.properties
Finally run this sample using the command:
kamel run SampleKafkaConsumer.java --config=configmap:kafka.props
To create messages to be read, use the producer command from the Strimzi page. Run in another terminal:
kubectl -n kafka run kafka-producer -ti --image=quay.io/strimzi/kafka:0.30.0-kafka-3.2.0 --rm --restart=Never -- bin/kafka-console-producer.sh --bootstrap-server my-cluster-kafka-bootstrap:9092 --topic my-topic
You should see a prompt where you can type messages to be sent to the my-topic topic.