Bug#910143: cloud.debian.org: Increase vagrant disk size

[Emmanuel Kasper <manu@debian.org>]

> Vagrant base boxes apparently use a maximum disk size of 10G.
OTOH the chosen format of the virtual disks does not allow to increase
the size (VBoxManage refuses to do so).

yes true. The reason is that during the build process, we convert the
raw disk image produced by packer to vmdk. Vmdk is kind of standardized,
whihc allows the generated image, coupled with the appropriate image, to
be in theory also imported by other hypervisors (vmware, Proxmox)

I see here a couple of solution:
 * you can convert using virtualbox the vmdk disk image to vdi, the
native virtualbox disk format, which can enlarged ( remember you need to
extend partitions and FS in the disk iamge too )

We could eventually change the build system to vdi but we would need to
check that:
a) a qemu-img vdi disk image works properly in virtualbox
b) an ovf export with a VDI disk image is properly imported in virtualbox
c) the build pipeline is adapted so it generates vdi disk images

if you can test a) I could take care of b) and c)

BTW what kind of software are you installing in the VM ?
I would have expected the shared /vagrant directory to host most of the
software depency