vagrant ssh-config

VBoxManage clonehd "ubuntu-bionic-18.04-cloudimg.vmdk" "hdd.vdi" --format vdi
VBoxManage modifyhd "hdd.vdi" --resize 102400
# remove all other disk for the instance, and add hdd.vdi
# now vagrant up
sudo cfidsk /dev/sda # remove /dev/sda2 if exists and expand sda1 to max
sudo resize2fs /dev/sda1