Independent from the chosen MQTT authentication type, the MQTT integration expses the following Prometheus metrics for monitoring.
The number of gateway events published by the MQTT integration (per event).
The number of commands received by the MQTT integration (per command).
The number of times the integration connected to the MQTT broker.
The number of times the integration disconnected from the MQTT broker.
The number of times the integration reconnected to the MQTT broker (this also increments the disconnect and connect counters).