+++ This bug was initially created as a clone of Bug #2190226 +++

Description of problem:
We'd like the ability to define mount units on the kernel command line. This allows the system to be booted into a snapshot of the system state (for e.g. using LVM2 CoW or thin provisioned snapshots) and enables rollback for system updates by allowing the administrator to preserve a copy of the prior system state and to optionally roll the system back to that state at a later time using the snapshot merge facility.

This would add new kernel command line syntax something like the following:

systemd.mount=what:where:fstype:options

The feature has been proposed to upstream systemd and has received some initial positive comments:

https://github.com/systemd/systemd/issues/27260

The new functionality would be added to the existing systemd-fstab-generator to write out mount units during early boot.

Version-Release number of selected component (if applicable):
systemd-239-68.el8

How reproducible:
100%

Steps to Reproduce:
1. man systemd-fstab-generator

Actual results:
No syntax exists for specifying kernel command line mount units.

Expected results:
The ability to specify mount units on the kernel command line

Additional info:
This will be used by Leapp and boom to provide rollback capable upgrades.