Switching to randomly generated hostnames

[Daniel Drake]

Hi,

Currently, XO hostnames are set on first boot in the following format:
xo-A-B-C
Where A, B and C are the last 3 bytes of the MAC address expressed in hex.

In Nicaragua we are seeing cases where XOs have no hostname set, both
on XO-1 and XO-1.5. On XO-1 this is presumably because libertas
usb8388 init was never 100% reliable, and on XO-1.5 its presumably
because the wireless card was DOA but was replaced after first boot.

When no hostname is set in this way, networking doesn't work properly,
since we don't create a network config (oops).

Also, the hostname must be unique within a group of peers for
avahi-based collaboration to work (as we've learnt from painful
experience).

We could harden up our initialisation to work better in the face of no
MAC address being available on first boot, but actually that is
becoming more complicated (due to increased parallelisation, the
network adapter will now come up late in boot). Moving to a simpler
scheme would solve the issues seen in the field and avoid the
challenges around network device initialisation.

I propose we move to generating hostnames in the same format as before
(xo-A-B-C), but with A, B and C assigned as random hex digits on first
boot.
(If people are worried about collisions, maybe we add a D digit.)

As far as I can see, the hostname is not really of relevance to
anything except avahi. It is not broadcast to the DHCP server when
connecting to a network, for example.

Any thoughts/objections?

Thanks,
Daniel