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Install Kafka using helm

1. Create a namespace for Kafka and switch the context to it:

   Code Block
   language bash
   kubectl create namespace kafka;

   Code Block
   kubectl config set-context --current --namespace=kafka

2. Add the repository for the Kafka Helm chart to your package manager.

   Code Block
   language bash
   helm repo add bitnami https://charts.bitnami.com/bitnami

   Code Block
   helm repo update

3. Deploy the Kafka server using the Helm chart. The below command deploys Kafka with 2 brokers (replicas).

   Code Block
   language bash
   helm upgrade --install kafka bitnami/kafka --namespace=kafka --set replicaCount=2

4. Please notice the output of the command above, it provides critical data that is used for the next steps

   1. Consumers can access Kafka via port 9092 on the following DNS name from within your cluster: kafka.kafka.svc.cluster.local

   2. The CLIENT listener for Kafka client connections from within your cluster has been configured with the following security settings: SASL authentication

   3. To connect a client to your Kafka:

      1. username="user1"

      2. To get the password execute the command below:(skip % at the end)

         Code Block
         language bash
         kubectl get secret kafka-user-passwords --namespace kafka \ -o jsonpath='{.data.client-passwords}' | base64 -d | cut -d , -f 1;

Configuring the Kafka Extension

Setting up the Kafka license as a ConfigMap

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1. HiveMQ Enterprise Extension For Kafka requires a separate license file, e.g. kafka-license.elic, in the $HIVEMQ_HOME/license directory. To add the kafka-license.elic along with the hivemq-license.lic, create a new configmap hivemq-license including all desired license files:

   Code Block
   language bash
   kubectl create configmap hivemq-license --namespace=hivemq \ --from-file hivemq-license.lic \ --from-file kafka-license.elic

2. Edit the values.yaml file of the hivemq-operator, section hivemq.configMaps. Update this:

   Code Block
   configMaps: [] # ConfigMaps to mount to the HiveMQ pods. These can be mounted to existing directories without shadowing the folder contents as well. #- name: hivemq-license # path: /opt/hivemq/license

   To this:

   Code Block
   configMaps: - name: hivemq-license path: /opt/hivemq/license

   This will mount the content of the configMap hivemq-license to the directory /opt/hivemq/license of the hivemq-broker pods.

Configuring the extension

1. Prepare a simple configuration file for kafka-extension as in the example below.

   • this example configuration will map all incoming MQTT publish packets to the topic “test” in Kafka; and will map the topic “test” in Kafka to the topic “test” in the HiveMQ broker

   • Use your password in <password>here_is_your_password</password>, that you successfully retrieved with this command a few steps ago:

     Code Block
     language bash
     kubectl get secret kafka-user-passwords --namespace kafka \ -o jsonpath='{.data.client-passwords}' | base64 -d | cut -d , -f 1;

   • Here is the file:

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3. Edit values.yaml file of hivemq-operator and update section hivemq.extensions, having name: hivemq-kafka-extension
   Update this:

   Code Block
   language yaml
   extensions: - name: hivemq-kafka-extension extensionUri: preinstalled enabled: false

   To this:

   Code Block
   language yaml
   extensions: - name: hivemq-kafka-extension extensionUri: preinstalled enabled: true configMap: kafka-config initialization: | # Fixes the location of the config.xml file [[ ! -f conf/config.xml ]] && [[ -f /conf-override/extensions/hivemq-kafka-extension/config.xml ]] && ln -s /conf-override/extensions/hivemq-kafka-extension/config.xml conf/config.xml

4. Re-deploy hivemq-operator with updated values.yaml

   Code Block
   language bash
   helm upgrade hivemq --install hivemq/hivemq-operator --values values.yaml --namespace hivemq

   – for ease of use we switch namespace back to hivemq kubectl config set-context --current --namespace=hivemq

Check if the license and configuration is applied correctly

If everything is correct,

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3. Kafka dashboard is visible in the HiveMQ Control Center:

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Testing Message Flow between HiveMQ Broker and Kafka using MQTT CLI

1. Subscribe a reference MQTT client to the topic “test”, The output shows the topic name and message: (please update your hostname with the DNS name or public IP address of your hivemq-hivemq-mqtt service, 20.113.46.120 in our test)

   Code Block
   language bash
   mqtt subscribe --topic '#' --host 20.113.46.120 --port 1883 -q 1 --showTopics

   Do not close this terminal session!

2. From a different terminal session, publish a message to the topic “test”:(please update your hostname with the DNS name or public IP address of your hivemq-hivemq-mqtt service, 20.113.46.120 in our test)

   Code Block
   language bash
   mqtt publish --topic test --message Hello --host 20.113.46.120 --port 1883 -q 1

3. If everything is correct, the subscriber will indefinitely receive the message we published. You can stop this by terminating the execution of the command by pressing Ctrl+C.

   Code Block
   mqtt subscribe --topic '#' --host $hivemqhost --port 1883 -q 1 --showTopics test: Hello test: Hello test: Hello test: Hello ........

4. the Kafka Dashboard in the HiveMQ Control Center shows incoming and outgoing Kafka messaging:

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