[Libguestfs] Notes on libguestfs with Ubuntu 12.04 (Precise)

[Richard W.M. Jones]

On Wed, Apr 04, 2012 at 02:08:33PM +0100, Richard W.M. Jones wrote:
> Ubuntu are now supplying a libguestfs package (or to be more accurate,
> they are just copying the Debian package) but it doesn't work out of the box.
> 
> There is a bug in apt which we worked around in febootstrap 3.14, but
> the supplied version of febootstap is only 3.12.  Hence you will get
> errors like this during installation:
> 
>   febootstrap: aptitude: error: no file was downloaded corresponding to package <some package name>
> 
> and you'll get the same error if you try to build from source.
> 
> The solution is to build febootstrap 3.14:
> 
>   cd /tmp
>   sudo apt-get build-dep febootstrap
>   sudo apt-get install devscripts
>   apt-get source febootstrap
>   wget http://people.redhat.com/~rjones/febootstrap/files/febootstrap-3.14.tar.gz
>   tar zxf febootstrap-3.14.tar.gz
>   cd febootstrap-3.14
>   rm -rf debian
>   cp -a ../febootstrap-3.12/debian .
>   vi debian/changelog
>   # change the first line: 3.12 -> 3.14
>   debuild -i -uc -us -b
> 
> That will create an febootstrap 3.14 .deb file in /tmp which you can
> install:
> 
>   sudo dpkg -i ../febootstrap_3.14-1_amd64.deb
> 
> Then you can go ahead and use the libguestfs package:
> 
>   sudo update-guestfs-appliance
> 
> or compile libguestfs from source.
> 
> There is another problem which you may hit, if you add a completely
> blank disk to libguestfs (this also affects libguestfs-test-tool):
> 
>   https://bugs.launchpad.net/ubuntu/+source/linux/+bug/931371
>   https://bugzilla.kernel.org/show_bug.cgi?id=42778

I've found a way around the last problem, which seems to be caused by
the version of qemu-kvm in Ubuntu, not the kernel.

If you compile qemu from source and use that, then it works (for me).

Do:

  git clone git://git.qemu.org/qemu.git
  cd qemu
  ./configure
  make

Then create a 'qemu.wrapper' file containing (edited):

  #!/bin/sh -
  qemudir=/home/user/d/qemu
  exec $qemudir/x86_64-softmmu/qemu-system-x86_64 -L $qemudir/pc-bios "$@"

and:

  chmod +x qemu.wrapper

(See: http://libguestfs.org/guestfs.3.html#qemu_wrappers )

Then set the environment variable:

  export LIBGUESTFS_QEMU=/home/user/d/qemu/qemu.wrapper

Then run libguestfs / virt-tools programs as normal (albeit slower
because it's qemu, not full upstream KVM).

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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