[lxc-users] Migrating a rootfs back-and-forth lxc 2.0 <=> 3.0

[Adrian Pepper]

Should one expect to encounter subtle (or perhaps not-so-subtle)
problems if one takes the rootfs of a simple container created under
one major version of lxc and uses it to replace the rootfs of a
container previously created under another major version?
(Replacing while the target is stopped, and then starting
the container after the replacement).

Assume that due diligence was done to keep the hostname in the
filesystem was consistent with lxc.uts.name (or its equivalent
in the relevant version), etc.

Or should one expect this to work seamlessly?  (The question would be
whether there are hooks of some sort under the rootfs which might get
automatically migrated in one direction (presumably "forwards" to a
higher version), but not in the other direction, or possibly not in
either direction at all).

Somewhat similarly, but conversely, I would assume that there is never
any situation where having the same rootfs used simultaneously by more
than one executing container would not be disastrous.  (in my case just
a foreseeable possible accident, not something I have visions of exploiting).


Adrian Pepper
arpepper at uwaterloo.ca