Notes on partman-auto:

- specifying partman-auto/method of "lvm" forces the automatic creation
  of a physical volume (of around 100GB; way too small) and forces the
  volume group name to be the same as the DHCP hostname.  This is
  overrideable via undo

- $lvmok{ } tags are secretly required

20000 50000 256000 lvm
        $primary{ } $defaultignore{ }
        method{ lvm } .