[Libguestfs] virt-builder fail with "bridge ‘virbr0’ not found" (fixed by LIBGUESTFS_BACKEND=direct ?!)

[Richard W.M. Jones]

On Wed, Oct 10, 2018 at 04:22:36PM +0300, Nir Soffer wrote:
> On Wed, Oct 10, 2018 at 2:49 PM Daniel P. Berrangé <berrange at redhat.com>
> wrote:
> 
> > On Wed, Oct 10, 2018 at 02:27:44PM +0300, Nir Soffer wrote:
> > > On Wed, Oct 10, 2018 at 10:18 AM Pino Toscano <ptoscano at redhat.com>
> > wrote:
> > >
> > > > On Tuesday, 9 October 2018 20:16:04 CEST Nir Soffer wrote:
> > > > > I'm trying to build fedora-27 image for testing uploads:
> > > > >
> > > > > $ virt-builder fedora-27 -o /var/tmp/fedora-27.img
> > > > > ...
> > > > > [  25.2] Opening the new disk
> > > > > virt-builder: error: libguestfs error: bridge ‘virbr0’ not found.
> > Try
> > > > > running:
> > > > >
> > > > >   brctl show
> > > > >
> > > > > to get a list of bridges on the host, and then selecting the
> > > > > bridge you wish the appliance network to connect to using:
> > > > >
> > > > >   export _SETTINGS=network_bridge=<bridge name>
> > > >
> > > > The libvirt backend uses a network bridge on the host to setup the
> > > > networking in the guest, which is enabled by default in virt-builder.
> > > >
> > >
> > > OK, now it is clear why bypassing libvirt avoids this issue.
> > >
> > > So maybe I'm missing some libvirt package required for creating the
> > > bridge?
> > >
> > > libvirt is installed by vdsm, which requires:
> > > libvirt-client
> > > libvirt-daemon-config-nwfilter
> > > libvirt-daemon-kvm
> > > libvirt-lock-sanlock
> > > libvirt-python
> >
> > virbr0 is provided by the libvirt default virtual network, which
> > sets up NAT based forwarding
> >
> > VDSM doesn't want this network connectivity so it doesn't install
> > the libvirt default network, hence you don't have any virbr0.
> >
> > You can get it by installing the libvirt-daemon-config-network RPM
> >
> 
> So maybe libguestfs-tools-c should depend on it?

It should probably only be a "Recommends", but yes I agree.  (Also
it's a dependency of libguestfs itself, not just the tools, since
anything that wants networking might need it.)

I pushed this change to Fedora 30+:

https://src.fedoraproject.org/rpms/libguestfs/c/3c0504323ef572cfe0b6d8158d4c61c9e49ce7f7?branch=master

Rich.

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