Non-live install for portable, non-installable Linux system?

https://askubuntu.com/a/1118412/1210606

@ChanganAuto: That seems unrelated to what I'm asking though.

How so? It thoroughly explains how to have a full installation in an external drive that's portable between systems even if very different (BIOS and UEFI). This answers your "might be missing something" (indeed you are because a normal installation only boots in the machine it was installed, there are a few more steps to make it portable). And no, you don't have to worry with machine ID, network conflicts are an entirely different story but has nothing to do with the system's portability.

If you want the device to boot on both BIOS and UEFI machines, you might look at this link: https://askubuntu.com/questions/1403792/how-to-create-a-full-install-of-ubuntu-22-04-to-usb-device-step-by-step I think this should work on USB-C NVMe, but I have not tried that.

@C.S.Cameron: The problem is not installing Ubuntu. I know how to do that. The question is about whether there are any differences between live boots and normal installs. For instance, should I reset/unset machine-id during boot? I'm guessing that I should also unset some networking stuff, but is that correct and what should I do? Things like that, is what I'm asking. I use to do this all the time back in the days, but there's been so many changes since then.

I just plug in my full install USB, as made above, then push the on button with F9 held down, (it is an HP), and select an OS in GRUB. The USB is a Full install just like the internal drive, there is no Live boot. see also https://askubuntu.com/a/1330458/43926

@C.S.Cameron: But are you using it as a portable system or just as an external drive for a single computer? Because making it portable is the question. For instance, when you request an IP from your DHCP server, it is based on the value of /etc/machine-id, so you need to deal with that when you make a golden image for cloning, for instance, because otherwise, you will get network conflicts when you boot the clones. Thus, I can't just make an Ubuntu install and flash it to a USB device, because I will get network conflicts. I'm asking what issues I need to deal with in that scenario.

@Jo-Erlend Schinstad: All Live installs for the same version of Ubuntu have the same UUID because they are clones, as you said. GParted has an option to create a new UUID that gets around this. It will work with Live or persistent installs made using Rufus, Universal, or mkusb. It will not work with ISO9660 type installs made using dd, Etcher, SDC, or Gnome-Disks, Ventoy is a challenge. A Full install made per my above link, is the same as an internal install except it will boot in BIOS mode or UEFI mode. UUID's for each install are unique. See also: https://askubuntu.com/a/1330458/43926

@C.S.Cameron: You're talking about filesystem UUID? That's something else. Every time you boot a live Ubuntu image, the value of /etc/machine-id is generated randomly at boot instead of at image creation, because otherwise, different users of the same live image would get the same IP on the network, which would generate conflicts. So this is the type of differences I'm looking for between a live session and an installed session, where the machine-id is permanent. It's just so difficult to know what I _don't_ know. :)

@Jo-Erlend Schinstad: I am not understanding why fully installing Ubuntu Desktop normally on the NVMe does not work for you? I don't think Ubuntu cares if it is installed internally or externally.

@C.S.Cameron: I have given the example of machine-id, where your networking will not work when multiple computers claim to be the same machine on the network, because IP addresses need to be unique. This is an example of a thing that I am aware of, but I'm asking about what if anything, I'm _unaware_ of.

I sit in a Tesla and translated this thread with Ai: