RabbitMQ runs with the MQTT plugin, but with constant error messages

[Developer]

RabbitMQ runs fine with mqtt in statefulset, but I keep getting error messages. crasher: 2023-03-21 20:35:25.318524+00:00 [error] <0.9964.8> initial call: rabbit_mqtt_reader:init/1 2023-03-21 20:35:25.318524+00:00 [error] <0.9964.8> pid: <0.9964.8> 2023-03-21 20:35:25.318524+00:00 [error] <0.9964.8> registered_name: [] 2023-03-21 20:35:25.318524+00:00 [error] <0.9964.8> exception error: no function clause matching 2023-03-21 20:35:25.318524+00:00 [error] <0.9964.8> rabbit_mqtt_reader:do_terminate(shutdown,undefined) (rabbit_mqtt_reader.erl, line 226) What can be the cause?

[David Ansari]

This is fixed in the upcoming RabbitMQ 3.12 release.

Please try out your MQTT workload using docker image rabbitmq:3.12-rc-management

See also https://blog.rabbitmq.com/posts/2023/03/native-mqtt/ about more 3.12 MQTT improvements.

[Developer]

That worked, thank you very much!

[Developer]

Unfortunately since rabbitmq:3.12-rc-management I no longer see any message rates in the management tool. they are all =0

[David Ansari]

Thanks for your feedback.

Yes, as mentioned in https://github.com/rabbitmq/rabbitmq-server/pull/5895 some rabbitmq_management metrics no longer work with Native MQTT in 3.12.

You can still see metrics from Connections (e.g. network traffic from / to client) and from Classic Queues and Quorum Queues (e.g. how many messages they contain).

The Message Rates are indeed no longer shown for MQTT traffic in the Management UI. This behaviour is similar to RabbitMQ Stream connections. MQTT connections in 3.12 and RabbitMQ Stream connections do not use the Channel process anymore.

We recommend using Prometheus for monitoring. Global counters (https://github.com/rabbitmq/rabbitmq-server/blob/main/deps/rabbitmq_prometheus/metrics.md#global-counters) are working with Native MQTT in 3.12.

See also our 4.0 deprecation announcements: https://blog.rabbitmq.com/posts/2021/08/4.0-deprecation-announcements/#disable-metrics-delivery-via-the-management-api--ui