I would like to add some stuff to the advanced guide.
I see that lxd-p2c is still updated etc., so it might be useful for some people.
I assume the instructions below are still recent? HOWTO use lxd-p2c
With the basic command being: lxd-p2c <existing lxd server/cluster> <new container name> <filesystem(s) to transfer>
Are there restrictions, like only certain linux distros are supported etc.?
Are there other measures or options to consider?
Is it possible to use an ISO file (of an OS) to create a container?
Yeah, lxd-p2c should still work as described.
The binary is static so as long as the distro has rsync, things should work.
Whether the container will behave afterwards, that’s where things can get tricky and need manual intervention, but lxd-p2c itself is a very simple program, it just connects to the LXD migration API and shoots an rsync stream from an existing system.
As for getting a container from an ISO, no, that’s not really possible.
You could install a virtual machine and then use lxd-p2c in it to turn it into a container if you really want to, but most distributions have some alternative tool to just build a chroot which is a lot better suited for containers.