[libvirt] [PATCH 19/41] remote: introduce virtproxyd daemon to handle IP connectivity
Daniel P. Berrangé
berrange at redhat.com
Mon Jul 29 13:20:32 UTC 2019
On Mon, Jul 29, 2019 at 01:50:22PM +0100, Daniel P. Berrangé wrote:
> On Mon, Jul 29, 2019 at 01:30:42PM +0100, Daniel P. Berrangé wrote:
> > On Sun, Jul 28, 2019 at 04:42:52PM +0200, Andrea Bolognani wrote:
> > > On Tue, 2019-07-23 at 17:02 +0100, Daniel P. Berrangé wrote:
> > > [...]
> > > > - We can make virtproxyd and the virtXXXd per-driver daemons all
> > > > have "Conflicts: libvirtd.service" in their systemd unit files.
> > > > This will guarantee that libvirtd is never started at the same
> > > > time, as this would result in two daemons running the same driver.
> > > > Fortunately drivers use locking to protect themselves, but it is
> > > > better to avoid starting a daemon we know will conflict.
> > >
> > > I feel like this will need to be tested extensively to make sure
> > > we're always doing the right thing, including on non-systemd hosts.
> >
> > Testing is quite easy - just try to start the two units and make
> > sure only one ends up running. Similarly for non-systemd hosts,
> > start both daemons & see that only one succeeds - the others
> > fail with lock conflict.
> >
> >
> > > > +++ b/src/remote/virtproxyd.service.in
> > > > @@ -0,0 +1,24 @@
> > > > +[Unit]
> > > > +Description=Virtualization daemon
> > > > +Conflicts=libvirtd.service
> > > > +Requires=virtproxyd.socket
> > > > +Requires=virtproxyd-ro.socket
> > > > +Requires=virtproxyd-admin.socket
> > > > +After=network.target
> > > > +After=dbus.service
> > > > +After=apparmor.service
> > > > +After=local-fs.target
> > > > +After=remote-fs.target
> > > > +Documentation=man:libvirtd(8)
> > > > +Documentation=https://libvirt.org
> > >
> > > There are a few non-obvious changes between libvirtd.service.in and
> > > this file:
> > >
> > > -Requires=virtlogd.socket
> > > -Requires=virtlockd.socket
> > > -Wants=systemd-machined.service
> > > -Before=libvirt-guests.service
> > > -After=iscsid.service
> > > -After=systemd-logind.service
> > > -After=systemd-machined.service
> > >
> > > I can see why we'd move the relationships with iscsid and virtlockd
> > > to virtstoraged, except looking ahead to patch 23 I see you haven't
> > > actually done that; either way, I'm not so convinced about the
> > > remaining changes. Care to explain the rationale behind them?
> >
> > virtproxdy contains no drivers, so it doesn't need to depend
> > on any of these services.
> >
> > virtdstoraged/qemud/lxcd should have gained some of these though.
>
> I should have killed dbus.service and remote-fs.service too.
Doh, not. dbus must always be present for polkit to work. remote-fs.service
is ok as that's only needed for the hypervisor services (to access disk
images).
Regards,
Daniel
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