Let’s hope that the students now are keen to understand how things work. There are several topics worth investigating:
The MQTT protocol itself.
Maybe Python programming is worth exploring?
Securing the MQTT protocol is interesting as well. How it’s done depends on the broker. In this setup Mosquitto is used. ACL’s are discussed here:mosquitto.conf SSL Security is discussed on many pages, such as this one which uses Let’s Encrypt, or this one using Self signed certificates
Diagnosing MQTT problems
Has it’s own page: www.nodered.org.
Both Mosquitto and Node RED can be run in Docker containers. The latest Raspberry Pi’s are great to learn container basics and more. If you go all the way you can build your own cluster. Check this blog to get started.
The more we discover, the closer we get to the OS (Raspbian) which is a Linux based OS. Managing the Mosquitto and Node RED services requires knowledge about service managemet.
Updating the server requires OS knowledge and installing software as well.
A good definition of usefull (required?) skills for novices are defined by LPI with the Linux Essentials exam as the proof of the pudding.