The systree functionality is enabled by default and reports the broker metrics at a fixed interval defined in the vernemq.conf. The metrics defined here are transformed to MQTT topics e.g. mqtt_publish_received is transformed to $SYS/<nodename>/mqtt/publish/received. <nodename> is your node's name, as configured in the vernemq.conf. To find it, you can grep the file for it: grep nodename vernemq.conf
The complete list of metrics can be found here.
This option defaults to 20000 milliseconds.
If the systree feature is not required it can be disabled in vernemq.conf
The feature and the interval can be changed at runtime using the vmq-admin script.
Usage: vmq-admin set = ... [[--node | -n] | --all]
Example: vmq-admin set systree_interval=60000 -n VerneMQ@127.0.0.1
Examples: