I no longer work in data centers, but in the past had success with both https://opendcim.org/ https://opendcim.org/ and https://www.racktables.org/ https://www.

I no longer work in data centers, but in the past had success with both https://opendcim.org/ https://opendcim.org/ and https://www.racktables.org/ https://www.racktables.org/. RackTables is probably a little simpler for managing just a few cabinets worth of things.