Open Stack

"Daniel P. Berrange" <berrange at redhat.com> wrote on 08/11/2014 11:39:25 
AM:

> From: "Daniel P. Berrange" <berrange at redhat.com>
> To: Matt Riedemann <mriedem at linux.vnet.ibm.com>
> Cc: 
> Date: 08/11/2014 11:49 AM
> Subject: Re: [Openstack] [nova] Libvirt driver domain metadata - add
> instance metadata dictionary?
> 
> On Fri, Aug 01, 2014 at 03:47:48PM -0500, Matt Riedemann wrote:
> > 
> > 
> > On 7/31/2014 6:58 AM, Markus Zoeller wrote:
> > >The blueprint "libvirt-driver-domain-metadata" introduces some of the
> > >istances properties to the `libvirt.xml` file. For example the name
> > >of the instance, the name of the flavor and the creation date.
> > >
> > >Would it make sense to add the instance.metadata dictionary also?
> > >
> > >API: /v2/​{tenant_id}​/servers/​{server_id}​/metadata
> > >Code: https://github.com/openstack/nova/blob/master/
> > >       nova/objects/instance.py#L148
> > >
> > 
> > You could ask danpb in #openstack-nova IRC about his thoughts, but 
looking
> > at the spec and code it looks like a specific metadata schema was in 
mind.
> > The metadata that a user can pass in when spawning an instance is 
arbitrary
> > so it wouldn't really fit into the schema created unless that was 
modified
> > to add some custom values, which would be the user metadata.
> > 
> > Is there a use case for putting user metadata in there?  Looks like 
the
> > blueprint is for adding specific metadata so an admin can correlate 
his
> > libvirt domains against nova API calls.
> 
> The intent was primarily to aid in debugging libvirt by providing 
information
> that is/was relevant to the libvirt guest configuration.
> 
> The instance metadata dict is not something that affects libvirt - IIRC 
it
> is only relevant to the guest OS, so i don't think it is relevant to 
include
> in the libvirt XML
 
Maybe the direction I'm heading is wrong. My intention is to enable a 
correlation
between multiple libvirt domains independent from their flavor.
E.g.
--------------     --------------    --------------
| Server: A  |     | Server: B  |    | Server: C  |
| Flavor: X  |     | Flavor: X  |    | Flavor: Y  |
| Group: foo |     | Group: bar |    | Group: foo |
--------------     --------------    --------------

I'd like to enable the hypervisor to understand that server A and C are 
correlated
because of the same "Group: foo". Is there already another mechanism which 
enables 
that?