Code review comment for lp:~lamont/maas/bug-1553665

Looks good to me.

My only concern about this branch is whether or not 3 minutes is enough. I don't know if I trust PXE/EFI environments to follow DHCP standards fully and renew their leases at the appropriate times.

But I suppose we'll find out. ;-) Just something to consider, in case you want to make it maybe 5-10 minutes.