Re: [Qemu-devel] [PATCH 1/1] If user doesn't specify a uuid, generate a random one

[Serge E. Hallyn]

Quoting Anthony Liguori (address@hidden):
> On 03/26/2012 10:13 AM, Serge E. Hallyn wrote:
> >Currently, if the user doesn't pass a uuid, the system uuid is set to
> >all zeros.  This patch generates a random one instead.
> >
> >Is there a reason to prefer all zeros?  If not, can a patch like this
> >one be applied?
> >
> >Signed-off-by: Serge Hallyn<address@hidden>
> 
> The other hypervisors don't have a concept of a transient guest like QEMU 
> does.

True, and I generally don't like arguments of the form "but (some other)
does it like this," but...

> There is no state preserved between invocations of QEMU.

Right, and I really don't know how many users (besides me) run kvm
by hand, as opposed to using libvirt or testdrive.  Perhaps testdrive
should be extended.

> Setting a random UUID doesn't seem like the right answer to me as it
> would potentially break Windows VMs.
> 
> Perhaps if the DMI UUID isn't set, you could look at the root filesystem's 
> UUID?

Interesting idea.  I don't know enough to know at which point in the code
qemu would know that, but I can take a look.

> Not all platforms have a notion of platform UUID so as Ubuntu
> supports more architectures, this problem would have to be dealt
> with eventually.

So it sounds like in this form certainly it's nacked :)

thanks,
-serge