Re: [Xen-devel] Re: [Xen-users] creating a domU with a particular UUID with xen-unstable

[Tim Freeman <tfreeman@xxxxxxxxxxx>]

On Mon, 31 Oct 2005 18:12:52 -0500
"Andrew D. Ball" <aball@xxxxxxxxxx> wrote:

> It looks like I can do this by starting a domain from an SXP directly 
> instead of a Python-based configuration.
> 
> If I use a suitable algorithm for generating UUIDs, I should be able to 
> guarantee at least an extremely low probability of UUID collisions 
> across an entire farm of systems running Xen.  I will read up some more 
> on the ISO UUID algorithm commonly used by hardware manufacturers.  I 
> don't trust it quite yet, but it does seem that this is in line with its 
> purpose.

I don't think Xen3 has changed, with UUIDs you'll run into this bug (for which I
have not yet submitted a patch for, I should do that). 

http://lists.xensource.com/archives/html/xen-devel/2005-07/msg00090.html

I was hastily adding support for UUIDs to the Globus workspace control program
and ran up against this problem because UUIDs can start with digits. Because I
couldn't wait to rely on a Xen patch, what I ended up doing for that was
stripping digits from the beginning of the UUID before sending it to Xen which
is clearly only a temporary hack. 

Tim 


> I'm not really fond of the behavior of domain name collisions.  I don't 
> want to have to query some sort of farm-wide database to see if a domain 
> name isn't being used to guarantee uniqueness, but I want to be able to 
> guarantee that I'll never have a domain name collision when doing a live 
> migration of a domU to another system.  They are nice to have around for 
> being easily readable by humans though.
> 
> Thanks for your help.
> 
> Andrew
> 
> Anthony Liguori wrote:
> > Andrew D. Ball wrote:
> > 
> >> Is it possible with xen-unstable (hopefully soon to be Xen 3.0) to 
> >> create a domU with a particular UUID?  I don't want the UUID for a 
> >> domain to change when I destroy it and create it again from the same 
> >> configuration.
> > 
> > 
> > You could always make the domain's name it's UUID.
> > 
> > Regards,
> > 
> > Anthony Liguori
> > 
> >> This doesn't necessarily have to have anything to do with xenstore's 
> >> being persistent, it could just involve a configuration option similar 
> >> to the one for virtual NICs where MAC addresses can be assigned 
> >> explicitly if desired but will be pseudo-randomly generated otherwise.
> >>
> >> Thanks for your help.
> >>
> >> Andrew
> >>
> >>
> >>
> >> _______________________________________________
> >> Xen-users mailing list
> >> Xen-users@xxxxxxxxxxxxxxxxxxx
> >> http://lists.xensource.com/xen-users
> >>
> > 
> > 
> 
> 
> 
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> 

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