Re: Switch livemedia-creator to qemu instead of virt-install

On Sun, Dec 20, 2015 at 06:45:40PM -0600, Dennis Gilmore wrote:
> On Friday, December 18, 2015 05:26:01 PM Brian C. Lane wrote:
> > I'm considering switching lmc to use qemu directly instead of
> > virt-install+libvirtd.
> > 
> > Currently lmc can use virt-install to create the full range of supported
> > images. But this doesn't work when running inside mock, which is used by
> > Fedora releng's koji system.
> > 
> > It also supports the --no-virt mode which runs anaconda directly in the
> > same environment as lmc. The benefit is less things to setup
> > and it works inside mock. But the drawback is that it uses device-mapper
> > for installing to a partitioned disk image, and device-mapper doesn't
> > work inside mock. So when running in mock you can only create a live iso
> > or a filesystem image, not anything that needs a partitioned disk.
> > 
> > I've been doing some experimenting and it ends up that qemu works inside
> > mock.
> > 
> > Switching to qemu (with optional auto-detection of when it could use
> > qemu-kvm to speed things up) would simplify the code and allow it to
> > create all the image types no matter where it is run from. It is also
> > possible (I haven't tried this yet) that it could be used to create
> > cross-arch images as well, since qemu has a wide range of supported
> > arches.
> 
> Would not be opposed to the change, it should work on platforms where we have 
> no hardware virt capability. We (releng) are reaching out to the lvm team to 
> see what can be done to make device-mapper work in a chroot, if it is 
> possible. 
> 
> Switching to using qemu would require lmc to learn a lot of details about 
> running vms for different arches. But it would enable making images for non 
> native arches as the commands are mostly the same. 

True, I'd encapsulate all that in a way that would make it easy to
extend or modify. I think the ability to make images for other arches
would be a big plus, even if it is a bit slow.

> 
> To use kvm would we need to bind mount /dev/kvm into the chroot?

I haven't tried that yet, but at a minimum, yes. I'm not sure what else
is needed to make qemu-kvm work.

-- 
Brian C. Lane | Anaconda Team | IRC: bcl #anaconda | Port Orchard, WA (PST8PDT)