Comment 15 for bug 1573095

Here is a workaround (or better said two) I am using (after converting it to raw) to get it work in Proxmox:

sudo kpartx -a xenial-server-cloudimg-amd64-disk1.raw
sudo mkdir -p /tmp/foo && sudo mount /dev/mapper/loop0p1 /tmp/foo

replace console=ttyS0 from

/tmp/foo/boot/grub/grub.cfg
/tmp/foo/etc/default/grub

with net.ifnames=0

sudo umount /tmp/foo
sudo kpartx -d xenial-server-cloudimg-amd64-disk1.raw