Cleaver, Japheth (jcleaver(a)soe.sony.com) said:
A ton of this work was already done in initscripts through the use of
the /etc/sysconfig/readonly-root hooks. Isn't that already working well enough now for
that purpose, future systemd changes aside?
Given that it involves bind-mounting *files* in some cases (which imparts
some truly odd semantics that confuse programs), it's not quite enough for
generalizing to any use. It certainly can be made to work, though.
Bill