First steps

After going through the Installation section and having installed all the operators, you now deploy a Kafka cluster and the required dependencies. Afterward you can verify that it works by producing test data into a topic and consuming it.

Setup

Two things need to be installed to create a Kafka cluster:

A ZooKeeper instance for internal use by Kafka
The Kafka cluster itself

Create them in this order by applying the corresponding manifest files. The operators you just installed then create the resources according to the manifest.

ZooKeeper

Create a file named zookeeper.yaml with the following content:

---
apiVersion: zookeeper.stackable.tech/v1alpha1
kind: ZookeeperCluster
metadata:
  name: simple-zk
spec:
  image:
    productVersion: 3.9.2
  servers:
    roleGroups:
      default:
        replicas: 1

and apply it:

kubectl apply -f zookeeper.yaml

Create a file kafka-znode.yaml with the following content:

---
apiVersion: zookeeper.stackable.tech/v1alpha1
kind: ZookeeperZnode
metadata:
  name: simple-kafka-znode
spec:
  clusterRef:
    name: simple-zk

and apply it:

kubectl apply -f kafka-znode.yaml

Kafka

Create a file named kafka.yaml with the following contents:

---
apiVersion: listeners.stackable.tech/v1alpha1
kind: ListenerClass
metadata:
  name: external-unstable-ip
spec:
  serviceType: NodePort
  preferredAddressType: IP
---
apiVersion: kafka.stackable.tech/v1alpha1
kind: KafkaCluster
metadata:
  name: simple-kafka
spec:
  image:
    productVersion: 3.7.1
  clusterConfig:
    tls:
      serverSecretClass: null
    zookeeperConfigMapName: simple-kafka-znode
  brokers:
    config:
      bootstrapListenerClass: external-unstable-ip # This exposes your Stacklet outside of Kubernetes. Remove this property if this is not desired
      brokerListenerClass: external-unstable-ip # This exposes your Stacklet outside of Kubernetes. Remove this property if this is not desired
    roleGroups:
      default:
        replicas: 3

and apply it:

kubectl apply --server-side -f kafka.yaml

This creates the actual Kafka instance.

Verify that it works

Next you produce data into a topic and read it via kcat. Depending on your platform you may need to replace kafkacat in the commands below with kcat.

First, make sure that all the Pods in the StatefulSets are ready:

kubectl get statefulset

The output should show all pods ready:

NAME                                 READY   AGE
simple-kafka-broker-default          3/3     5m
simple-zk-server-default             3/3     7m

Then, create a port-forward for the Kafka Broker:

kubectl port-forward svc/simple-kafka-broker-default-bootstrap 9092 2>&1 >/dev/null &

Create a file containing some data:

echo "some test data" > data

Write that data:

kcat -b localhost:9092 -t test-data-topic -P data

Read that data:

kcat -b localhost:9092 -t test-data-topic -C -e > read-data.out

Check the content:

grep "some test data" read-data.out

And clean up:

rm data
rm read-data.out

You successfully created a Kafka cluster and produced and consumed data.

What’s next

Have a look at the Usage guide page to find out more about the features of the Kafka Operator.