I was looking at tools a while ago at Linode while trying to automate support for FreeBSD/OpenBSD/etc. The UX for different distributions (if provided at all) is disparate, confusing, and poorly documented. I ended up giving up and just building the images by hand and hosting them [0].

I've seen linuxkit a few times now but it didn't click that this is what it does.

The problem still remains that there's no good distribution-agnostic combination of boot image creator + provisioning system. The ideal situation is one tool that allows me to start with an arbitrary base distribution, provision it, and build a bootable image for the VM provider of my choice (VirtualBox, EC2, bhyve, etc.).

[0] https://github.com/eatonphil/linode_deploy_experimental