Host ID.

[Pawel Jakub Dawidek]

On Mon, Apr 09, 2007 at 01:35:39PM -0400, Jung-uk Kim wrote:
> On Sunday 08 April 2007 11:13 am, Pawel Jakub Dawidek wrote:
> > On Sun, Apr 08, 2007 at 10:04:16PM +0900, gnn at freebsd.org wrote:
> > > I noted that someone mentioned using a network based ID.  Since
> > > EUI-64 are unique I would suspect they would be the best source
> > > for this on systems that don't naturally have a hostid concept. 
> > > See Appendix A of RFC 2373 for how to create an EUI-64 Interface
> > > Identifier.
> > >
> > > The only problem with this approach that I see is that if you
> > > remove that interface (that is it was on a card not on your
> > > motherboard) then it goes away.  Perhaps generating this and
> > > storing it, no matter what the future network configuration of
> > > the system is, is the right way to go.
> >
> > So why not generate it and be done with it? And what if you move
> > your card to another box were you're planning to install new
> > system?
> 
> Actually uuidgen(2) uses uuid(3) and uuid(3) generates UUID version 1 
> string, i.e., it is based on timestamp and MAC address already. :-)

But in my proposal we generate UUID only once and store it as it is,
which means are keep the same UUID even if network card has changed.

> > I'd really like to make it simple and consistent on all archs, so
> > one knows exactly what to expect.
> 
> Agreed.  But I also agree with imp, i.e., we have to utilize hardware 
> UUID if it is available and valid for the platform.

I don't agree. As Robert pointed out there are situation you would like
to share the same UUID between many hosts.

I'm committing as it is, we may change it in the future.

-- 
Pawel Jakub Dawidek                       http://www.wheel.pl
pjd at FreeBSD.org                           http://www.FreeBSD.org
FreeBSD committer                         Am I Evil? Yes, I Am!
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