Describe the technical infrastructure (aka the underlying hardware) the system is running in. That shall include:
- nodes, i.e. processors, server, cluster… and their
- relations (channels), i.e. bus, network or wireless connections,
- additional hardware elements, i.e. firewall, router, switches, storage etc.
You could either use UML deployment diagrams or free-form graphics, like shown below:
(diagram by UML-diagrams.org)
In case your stakeholder like such graphical icons or symbols: use a consistent set of such symbols with a defined semantic!
Delegate hardware documentation
Try to delegate the hardware and infrastructure documentation to the appropriate stakeholders.