Automated Disk Image Creation via Packer

[naftulikay]

Hey all! So I'm an SRE-type and I'm familiar with creating custom machine images for various backends (AWS, KVM, etc.) using Packer, and I'd like to create an automated build system for elementary OS that I'm more than willing to contribute back to the community, will license it however the elementary team wants.

The main hurdle preventing me from doing so right now is not knowing how to kick off the automated installer on boot. I can use VirtualBox or KVM to create the image, but I'm not sure how to tell the ISO installer to just automatically install things. For my personal needs, I'll probably also export a tarball (stage 3) of the root filesystem to make it much easier for my personal installs on my laptops/desktops.

At minimum, a bootable machine image should be produced, but for my own custom stuff, I'd like to provision the new VM with some packages and configuration that are unique to the way I use elementary OS.

Can anyone help me figure out how exactly to trigger the unattended install? Once I've got that, I'll be able to write the Packer config and GitHub Actions workflow so that everything just works™.