I know that I can use virtual machine images for LXD from linuxcontainers.org. However, what if I want to launch a virtual machine from another image that’s not currently available?
I know there are ISO files for Ubuntu Server 23.04, but I’m not sure how I would go about launching an LXD virtual machine, since it uses a different container format.
There is the --empty option to lxc launch and lxc init commands, which then doesn’t use an image.
You can then install via an ISO by attaching it as a disk device.
See Run FreeBSD 13.1 / OPNsense 22.7 / pfSense 2.7.0 (and newer?) under LXD VM for how to add the disk device to boot off the ISO.
For Lunar Lobster builds you can also use the ubuntu-daily: remote to get access to the official cloud images.
lxc image list ubuntu-daily: | grep 23.04