Code review comment for lp:~mpontillo/maas/autocreate-fabrics-and-vlans

This still needs more unit tests written. But I'd like some additional eyes on this code before I move forward.

I've been testing this end-to-end and it seems to do what we want, at least for creating VLANs and fabrics automatically when the cluster registers.

Adding cluster interfaces by hand, (and editing existing interfaces to make changes that SHOULD probably put them in a different VLAN or Fabric) will most likely do the wrong thing still.