This is an example to build templates in Virtualbox for sysbuilder with Packer.
Run the following to get going:
packer build packer.json
The image should be converted to qcow:
tar -xvf ubuntu1204.ova # Extract .ova
qemu-img convert -O qcow ubuntu1204-disk1.vmdk template.qcow # Convert to .qcow
The image is an Ubuntu 12.04 with some specifics in /etc/rc.local. As sysbuilder removes
the SSH keys, the script in rc.local will create them again.