@nofroyo I would not attempt to install FOG directly on your QNAP device. The fog installer assumes it has full control of your device and may make changes that could potentially break the web ui of your QNAP. The other issue you have to consider is that the libraries needed install FOG may not be available because your QNAP doesn’t run a standard linux OS.
Running inside a vm would be a better choice is you MUST run everything on a single device. Performance may no be so great since most NAS devices use low end CPUs because NAS activities don’t require much CPU. If you are only doing image deployment without any FOG Clients in the mix it may be OK to use it on your NAS as a VM. I don’t know if anyone has done this before so you can be the first.
FOG doesn’t really need a lot of CPU, in a way it functions much like a NAS in that the FOG server’s job is moving data between storage and the network adapter. The target computer does all of the real heavy lifting during imaging, I’ve run FOG on a Pi3 and Pi4 without issue. You have to just be mind full that you are dealing with a small but efficient computer.