[one-users] Mandatory attributes with default value ?

[Olivier Berger]

On Mon, 21 May 2012 13:04:30 +0200, "Ruben S. Montero" <rsmontero at opennebula.org> wrote:
> Hi
> 
> As you outline in your email, there are some parameters which are
> mandatory for an specific hypervisor (and may not be mandatory for
> another one). So, in general OpenNebula will not know if the host use
> for the VM is going to be Xen, KVM or even EC2.
> 

OK, for the general case, but at the time instanciation will be
performed, the real hypervisor will be, so there could be a check at
that time, for instance of a lacking OS:ARCH when deploying for kvm.

> We came out with a defaults file, where you could put defaults for
> those hypervisor-mandatory attributes. This way we could keep the
> templates abstract enough, and there is no need to specify, let say
> BOOT for every single template.
> 

Hmmm... so, the intent is to have a same template which could be
deployed on hosts using different hypervisors on the same cloud ? I'm
not sure I understand the rationale. Could you elaborate a bit more ?

> Then, why not use that file also to provide defaults for specific
> hypervisor attributes (e.g. caching algorithm for I/O operation on
> DISK). Unfortunately the documentation lagged behind the new uses for
> the file....
> 
> Thanks for the heads up!
> 

You're welcome.

> We've already updated the documentaion, to (hopefully) better reflect this ;)
> 

I'm not sure I could spot the docs changes (3.4's ?)... but great if you could
improve it ;)


Anyway, back to the problem I exhibited : 
> >
> > Indeed, if the ARCH is not defined, I experience problems booting an
> > amd64 image on my amd64 host, since kvm is provided with some 32 bit
> > emulation param (-cpu qemu32, see http://bugs.debian.org/673173)
> >
> > Shouldn't the mandatory args be checked and an error reported ?
> >

Should I then file a bug report asking to removal of the default i686
for OS:ARCH in the case of kvm, and requesting addition of a check for
one explicit setting ?

Or maybe I didn't understand the meaning of these defaults... :-/

Thanks in advance.

Best regards,
-- 
Olivier BERGER 
http://www-public.it-sudparis.eu/~berger_o/ - OpenPGP-Id: 2048R/5819D7E8
Ingenieur Recherche - Dept INF
Institut Mines-Telecom, Telecom SudParis, Evry (France)