SAP Digital Manufacturing - subscribe to MQTT topics

[Fabi]

Hello,

I would like to subscribe to a MQTT topic in SAP Digital Manufacturing. The MQTT broker runs on the same machine as the SAP Production Connector. The process is as follows: A OPC UA server publishes events and alarms which are consumed by a Node-RED flow which further publishes the message as JSON to a Mosquitto MQTT broker and topic.

The problem now is that I am not able to connect to the MQTT broker from SAP Digital Manufacturing via Production Connector because I would have to upload a "Client Certificate" consisting of a private key, client certificate, CA certificate and root certificate in the .pem format according to SAP Help Portal. I've done that and also integrated the client key and all certificates into one .pem file. After uploading the certificate chain as single file into SAP Digital Manufacturing in the app "Manage Message Brokers", Section 3rd Party Brokers and Production Connectors, I receive the following error:

Couldn't upload Production Connector client certificate. Response: An error occurred while processing your request.

Any ideas how to further proceed here?

Thank you in advance for your help!

Best regards
Fabian

[Fabi · Accepted solution]

Hi,

if anyone also faces this problem, you will have to upload certificate chain (see SAP help portal -> MQTT brokers -> Production connectors) not in the page where you are able to generate a client certificate but on the page of basic information of the broker. Further, with Misquitto it seems to be difficult to authorize via client certificate, with Apache ActiveMQ it now works.

BR
Fabian