Expose MQTT port 1883 via Load Balancer and test message flow using MQTT CLI

Exposing ip via load balancer in the following steps makes it public. Please check out HiveMQ authentication and authorisation extensions to control client access and scope. https://www.hivemq.com/products/extensions/

Prequisite: A running HiveMQ Cluster and a values.yaml file Install HiveMQ on the AKS cluster

Enable load balancer

Open values.yaml and search for port 1883 under hivemq.ports.port

ports:
    - name: "mqtt"
      port: 1883
      expose: true
      patch:
        - '[{"op":"add","path":"/spec/selector/hivemq.com~1node-offline","value":"false"},{"op":"add","path":"/metadata/annotations","value":{"service.spec.externalTrafficPolicy":"Local"}}]'
        # If you want Kubernetes to expose the MQTT port to external traffic
        # - '[{"op":"add","path":"/spec/type","value":"LoadBalancer"}]'

Uncomment and expose the loadbalancer

ports:
    - name: "mqtt"
      port: 1883
      expose: true
      patch:
        - '[{"op":"add","path":"/spec/selector/hivemq.com~1node-offline","value":"false"},{"op":"add","path":"/metadata/annotations","value":{"service.spec.externalTrafficPolicy":"Local"}}]'
        # If you want Kubernetes to expose the MQTT port to external traffic
        - '[{"op":"add","path":"/spec/type","value":"LoadBalancer"}]'

Save the file and apply the changes

helm upgrade hivemq --install hivemq/hivemq-operator --values values.yaml

Check if the service for port 1883 has an external IP address now (in our case its hivemq-hivemq-mqtt)
```
kubectl get services
```

In case the external IP is not visible, you can uninstall hivemq and reinstall it again.

Uninstall HiveMQ
helm uninstall hivemq
Reapply the changes
helm upgrade hivemq --install hivemq/hivemq-operator --values values.yaml

Connect To Your HiveMQ Cluster

Once your HiveMQ cluster is up and running, you are ready to connect clients to the cluster with the MQTT-CLI. To obtain the exposed ENDPOINT of the created load balancer on which clients connect to your cluster, enter:

kubectl get hivemq-clusters

Output similar to the following displays: (20.79.151.169 in our case)

$ kubectl get hivemq-clusters
NAME     SIZE   IMAGE            VERSION     STATUS    ENDPOINT       MESSAGE
hivemq   3      hivemq/hivemq4   k8s-4.24.0   Running   20.79.151.169   Live updates completed successfully

Create a subscriber

mqtt sub -i SUB -h 20.79.151.169 -p 1883 -T -t '#'

Create a publisher and publish the message. This should send a message to the subscriber. Test: Hello

mqtt publish --topic Test --message Hello --host 20.79.151.169 --port 1883

You have now successfully connected a new MQTT client to a HiveMQ cluster hosted on Azure.

To learn more ways to interact with HiveMQ, see the MQTT-CLI documentation.