VirtualBox
VBoxManage Examples
VBoxManage is the command line tool used to interact with VirtualBox.
Create a new virtual disk image
https://www.virtualbox.org/manual/ch08.html#vboxmanage-createmedium
VBoxManage createmedium --format vdi --filename $DISK_NAME --size $DISK_SIZE_IN_MB
Attach storage to a vm
https://www.virtualbox.org/manual/ch08.html#vboxmanage-storageattach
VBoxManage storageattach $VM_NAME --storagectl $STORAGE_CONTROLLER --format vdi --filename $DISK_NAME --size $DISK_SIZE_IN_MB