[systemd-devel] Should user mode linux register with machined?

[Daniel P. Berrange]

On Fri, Oct 10, 2014 at 06:44:03PM +0200, Lennart Poettering wrote:
> On Wed, 17.09.14 10:24, Richard Weinberger (richard.weinberger at gmail.com) wrote:
> 
> > On Wed, Sep 17, 2014 at 1:09 AM, Zbigniew Jędrzejewski-Szmek
> > <zbyszek at in.waw.pl> wrote:
> > > On Tue, Sep 16, 2014 at 05:31:05PM +0200, Thomas Meyer wrote:
> > >> Hi,
> > >>
> > >> I wrote a small patch for user-mode linux to register with machined by
> > >> calling "CreateMachine". Is this a good idea to do so?
> > > Yes, this sounds useful. After all is just another mechanism of
> > > virtualization, and in this case can be treated similarly to
> > > containers and vms.
> > 
> > I still want a sane reason and a usecase for that.
> > Can someone please educate me? :-)
> > 
> > Please note that also qemu does not register itself to systemd.
> > libvirt does. I think going down this path makes also sense for UML
> > as libvirt has a UML driver too.
> > qemu and the UML ELF image are the low level building blocks.
> > Managers like libvirt should register the virtual machines created by
> > LXC, UML, qemu, etc.. to systemd.
> 
> It's a bit more complex. While UML, qemu, kvm, currently don't, LXC,
> systemd-nspawn and libvirt-lxc all do talk directly to machined. (Note
> that LXC and libvirt-lxc are separate codebases, the latter is *not* a
> wrapper around the former).

Libvirt registers both LXC & QEMU/KVM guests with machined.

We don't currently register UML guests with machined, but that
is simply because UML isn't really a high priority target for
people anymore and so hasn't been updated to use libvirt's
cgroup/systemd integration support. From the libvirt POV i'd
be happy to see patches to make it register with machined.

I'm not sure that standalone UML binaries need to directly
integrate/register with systemd - I tend to view it as a job
for whatever is managing UML to decide todo that.

Regards,
Daniel
-- 
|: http://berrange.com      -o-    http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org              -o-             http://virt-manager.org :|
|: http://autobuild.org       -o-         http://search.cpan.org/~danberr/ :|
|: http://entangle-photo.org       -o-       http://live.gnome.org/gtk-vnc :|