RE: [Xen-devel] [PATCH]: xl: use libuuid to generate random UUID's

[Gianni Tedesco <gianni.tedesco@xxxxxxxxxx>]

On Mon, 2010-08-09 at 11:51 +0100, Ian Jackson wrote:
> Ian Pratt writes ("RE: [Xen-devel] [PATCH]: xl: use libuuid to generate 
> random UUID's"):
> > The best approach is to generate locally administered MAC addresses
> > hence giving us 46 bits of freedom rather than XenSource registered
> > OUI addresses which have just 24 bits -- collisions will be *much*
> > less likely. Further, it's best not to generate random addresses
> > every time, but to derive the MAC address from a good hash of the VM
> > UUID and the NIC number so that they are deterministic.
> 
> VM uuids are not stable in xend nor xl.  Perhaps xl should hash the VM
> name, which is stable and supposedly unique.

But they can be made to be stable and I suppose this is the point here.
I think it makes more sense than unique names. In either case we would
need to bring in something like a SHA1 implementation I suppose. I'm not
sure I see much point in this myself but if the consensus is there I can
implement it.

As for portability issues, I think Egger is right about blktap2 approach
being the way to go.


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