It appears Linux root-on-ZFS is a mess. No standard way to do it. Kernel updates require recompiling ZFS. Boot environments are a cornucopia of constantly evolving hacks.
If you're actually using #ZFS on root, on #Debian, what's your preferred hack to make that happen? #sysadmin
I suspect #openzfsmastery might need to assume root on extFS and data on ZFS, leaving root-on-ZFS for the advanced user or a terminal chapter. 
Its tragic.
There is no SINGLE Linux distribution with installer that would allow you to install Linux with Root on ZFS - with ZFS Boot Environments - and with ZFSBootMenu integrated ... NONE. ZIP. Nada. Zero.
Not to even mention that it would also support LUKS encryption on Linux - no way.
On FreeBSD you have fully protected setup with ZFS Boot Environments supported in the loader and with GELI or not included.
The ZFS Boot Environments feature on Linux - the thing that is DESIGNED to PROTECT you from any disasters (that it works on FreeBSD and Illumos) is one that is most fragile and uncertain on Linux.
Michael W Lucas 
vermaden