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


  • To: "Andrew D. Ball" <aball@xxxxxxxxxx>
  • From: Kip Macy <kip.macy@xxxxxxxxx>
  • Date: Tue, 1 Nov 2005 10:40:11 -0800
  • Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
  • Delivery-date: Tue, 01 Nov 2005 18:37:16 +0000
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  • List-id: Xen developer discussion <xen-devel.lists.xensource.com>

It would seem to me that if you either seeded the UUID from the initial physical machine's MAC address (assuming that one can do that) or  if  you  concatenated a MAC address from the physical machine with a 64-bit time value that your odds of collision would be vanishingly small.


        -Kip

On 10/31/05, 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'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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