MQTT Broker

The technical documentation of the mqtt-broker microservice, which forwards MQTT messages between the other microservices.

The MQTT broker in the United Manufacturing Hub is HiveMQ and is customized to fit the needs of the stack. It’s a core component of the stack and is used to communicate between the different microservices.

How it works

The MQTT broker is responsible for receiving MQTT messages from the different microservices and forwarding them to the MQTT Kafka bridge.

Kubernetes resources

  • StatefulSet: united-manufacturing-hub-hivemqce
  • Service:
    • Internal ClusterIP:
      • Generic: united-manufacturing-hub-mqtt at port 1883 (MQTT) and 8883 (MQTT over TLS)
      • HiveMQ local: united-manufacturing-hub-hivemq-local-service at port 1883 (MQTT) and 8883 (MQTT over TLS)
      • VerneMQ (for backwards compatibility): united-manufacturing-hub-vernemq at port 1883 (MQTT) and 8883 (MQTT over TLS)
      • VerneMQ local (for backwards compatibility): united-manufacturing-hub-vernemq-local-service at port 1883 (MQTT) and 8883 (MQTT over TLS)
  • ConfigMap:
    • Configuration: united-manufacturing-hub-hivemqce-hive
    • Credentials: united-manufacturing-hub-hivemqce-extension
  • Secret: united-manufacturing-hub-hivemqce-secret-keystore
  • PersistentVolumeClaim:
    • Data: united-manufacturing-hub-hivemqce-claim-data
    • Extensions: united-manufacturing-hub-hivemqce-claim-extensions


Most of the configuration is done through the XML files in the ConfigMaps. The default configuration should be sufficient for most use cases.

The HiveMQ installation of the United Manufacturing Hub comes with these extensions:

If you want to add more extensions, or to change the configuration, visit the HiveMQ documentation.

Environment variables

Environment variables
Variable nameDescriptionTypeAllowed valuesDefault
HIVEMQ_ALLOW_ALL_CLIENTSWhether to allow all clients to connect to the brokerbooltrue, falsetrue
Last modified April 4, 2023: feat: version (75e2d11)