Check manual page of mqtt_messages

MQTT: Broker messages

Distribution Official part of Checkmk
License GPLv2
Supported Agents Mqtt
This check monitors message related statistics of a MQTT broker instance.

It shows the number of currently retained messages active on the broker. The number of bytes currently held by message payloads in the message store of the broker and the number of currently held messages in the message store.

Besides these values displaying the current state, it also shows the number and size of sent and received messages. It also shows these numbers separately for PUBLISH messages and the number of CONNECT messages received.

To make this check work you have to configure the special agent agent_mqtt which connects via MQTT to the broker to gather information from the $SYS/ topic.

This check has been developed with Mosquitto message broker but might also work with other brokers. The available values vary from broker to broker and from version to version.

Please note that this check may only be useful if you connect it directly to a broker. In case you want to monitor a multi-tentant cluster, this check is only useful if configure it for each node since the $SYS/ topic is is node specific. It is not useful to use this check through a load balancer.

The check is always OK.


The instance ID configured in the special agent.


One service is created for each instance.