I’ve been using ZFS root on Ubuntu without any such nonsense for years, but I had to debootstrap it manually.
See guides here: https://openzfs.github.io/openzfs-docs/Getting%20Started/Ubu...
With Ubuntu 20.04 the standard installer should support setting up a ZFS root without all that manual work, but I haven’t tested it myself.
There are ways to do chroot installs on RHEL but sadly not well documented.
Some resources on this:
- https://glacion.com/2019/06/16/Fedora.html
- https://github.com/glacion/fedora-chroot-installation
- https://web.archive.org/web/20150912004438/https://wiki.cent...
Most of that will work for RHEL with some minor modifications.
Pity it is not better documented.
Just set up your disk layout the way you want on a disk device or a loopback disk backed by an image, and do something like:
$ sudo dnf --installroot=/path/to/mounted/target group install @core @hardware-support
And you're good to go. You can see the list of groups available to include by using "dnf group list --ids".
If you opened the first link I shared you would see more is needed than this, which is why I linked to something explaining both this and the additional steps needed.
Then the only remaining part would be figuring out how to do zfs on root in redhat. I do it with a chroot bash script for Ubuntu server atm, but hopefully there's a debootstrap kind of thing on redhat that I can use as a base.