[systemd-devel] Possible systemd segfault switching from 216 to 219 in fedora upgrade

[Andrei Borzenkov]

В Fri, 13 Mar 2015 16:38:33 -0600
Chris Murphy <lists at colorremedies.com> пишет:

> On Fri, Mar 13, 2015 at 3:59 PM, Will Woods <wwoods at redhat.com> wrote:
> > I don't really like the new->old->new switchroot stuff, but I haven't
> > got a better solution at the moment.
> >
> > But: if we could use something like "systemd-nspawn" to:
> >
> > 1) start your old system in a container,
> > 2) let it mount its disks,
> > 3) copy/bind/move those mounts back out to the host somehow
> 
> Quite a while ago I suggested to Richard Hughes the idea of using
> systemd-nspawn and snapshots to get fully atomic updates when on LVM
> thinp volumes or Btrfs. It can work for major upgrades also.
> 
> First snapshot existing trees, start a container, mount the snapshots,
> update/upgrade them. If it fails, destroy the snapshots. If it
> succeeds, update bootloader config to boot the snapshots, and notify
> user for reboot.
> 

You do not really need snapshots for this. You just need extra space to
copy current boot environment. Using snapshots just allows to do it
with less space needed.