[openstack-dev] [nova] Create an instance with a custom uuid

Pasquale Porreca pasquale.porreca at dektech.com.au
Tue Sep 30 10:53:10 UTC 2014


Going back to my original question, I would like to know:

1) Is it acceptable to have the UUID passed from client side?

2) What is the correct way to do it? I started to implement this 
feature, simply passing it as metadata with key uuid, but I feel that 
this feature should have a reserved option rather then use metadata.


On 09/25/14 17:26, Daniel P. Berrange wrote:
> On Thu, Sep 25, 2014 at 05:23:22PM +0200, Pasquale Porreca wrote:
>> This is correct Daniel, except that that it is done by the virtual
>> firmware/BIOS of the virtual machine and not by the OS (not yet installed at
>> that time).
>>
>> This is the reason we thought about UUID: it is yet used by the iPXE client
>> to be included in Bootstrap Protocol messages, it is taken from the <uuid>
>> field in libvirt template and the <uuid> in libvirt is set by OpenStack; the
>> only missing passage is the chance to set the UUID in OpenStack instead to
>> have it randomly generated.
>>
>> Having another user defined tag in libvirt won't help for our issue, since
>> it won't be included in Bootstrap Protocol messages, not without changes in
>> the virtual BIOS/firmware (as you stated too) and honestly my team doesn't
>> have interest in this (neither the competence).
>>
>> I don't think the configdrive or metadata service would help either: the OS
>> on the instance is not yet installed at that time (the target if the network
>> boot is exactly to install the OS on the instance!), so it won't be able to
>> mount it.
> Ok, yes, if we're considering the DHCP client inside the iPXE BIOS
> blob, then I don't see any currently viable options besides UUID.
> There's no mechanism for passing any other data into iPXE that I
> am aware of, though if there is a desire todo that it could be
> raised on the QEMU mailing list for discussion.
>
>
> Regards,
> Daniel

-- 
Pasquale Porreca

DEK Technologies
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