On Fri, 13.03.15 01:16, Zbigniew Jędrzejewski-Szmek (zbys...@in.waw.pl) wrote:
> On Tue, Mar 10, 2015 at 10:23:23PM +0100, Tobias Hunger wrote: > > On Tue, Mar 10, 2015 at 9:33 PM, Tobias Hunger <tobias.hun...@gmail.com> > > wrote: > > >> presets and machined ID are applied by PID 1, before it begins with > > >> starting any units, hence *really* early on. Note though that actually > > >> /etc/machine-id is used as flag for "is /etc empty". If the file > > >> exists it is assumed that /etc is provisioned properly. If it is > > >> missing PID 1 will generate the machiend id and apply presets. > > > > > > An OS installer could put the machine-id into /usr just fine (and so > > > can I) and systemd could just get it from there if available before > > > generating a new one. > > > > > > It would be nice if the machine-id did not change during to a factory > > > reset: It is used in the logs and changing it will basically make > > > historical log data much harder to analyze. IIRC networkd also uses it > > > to generate persistent MAC addresses for containers and such. > > > > > > So far this seems to be the only critical piece of information that > > > can not get restored via tmpfiles.d. > > > > Thinking about this a bit longer: /usr does not seem like a good idea. > > The machine-id is supposed to be unique and usr-images are meant to be > > reused. > > > > Maybe provide a kernel command line option to force the machine-id if > > none is set yet? > I think this could be an option. We currently check > /var/lib/dbus/machine-id, $container_uuid, and /sys/class/dmi/id/product_uuid. > I think that the first should work for your use case, since you keep /var. > But we also check some commandline option, this seems useful for some > use cases. I think /var/lib/dbus/machine-id is nothing to use here. It purely exists for compat with upgrades from classic dbus1 systems, where we should avoid inventing a new machine id, if the dbus one is fine. I'd be fine with adding a kernel switch to make this configurable, as Zbigniew suggested. Lennart -- Lennart Poettering, Red Hat _______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
