[Engine-devel] Report vNic Implementation Details

[Dan Kenigsberg]

On Thu, Nov 22, 2012 at 09:55:43AM +0200, Livnat Peer wrote:
> On 22/11/12 00:02, Itamar Heim wrote:
> > On 11/21/2012 10:53 PM, Andrew Cathrow wrote:
> >>
> >>
> >> ----- Original Message -----
> >>> From: "Moti Asayag" <masayag at redhat.com>
> >>> To: engine-devel at ovirt.org
> >>> Sent: Wednesday, November 21, 2012 12:36:58 PM
> >>> Subject: [Engine-devel] Report  vNic Implementation Details
> >>>
> >>> Hi all,
> >>>
> >>> This is a proposal for reporting the vNic implementation details as
> >>> reported by the guest agent per each vNic.
> >>>
> >>> Please review the wiki and add your comments.
> >>
> >>
> >> While we're making the change is there anything else we'd want to
> >> report - MTU, MAC (since a user might try to override), etc ?
> >>>
> >>> http://wiki.ovirt.org/wiki/Feature/ReportingVnicImplementation
> > 
> > iirc, the fact ip addresses appear under guest info in the api and not
> > under the vnic was a modeling decision.
> > for example, what if guest is using a bridge, or a bond (yes, sounds
> > unlikely, but the point is it may be incorrect to assume ip-vnic relation.
> > michael - do you remember the details of that discussion?
> 
> I'd love to know what drove this modeling decision.
> The use case above is not a typical use case.
> We know we won't be able to present the guest internal network
> configuration accurately in some scenarios but if we cover 90% of the
> use cases correctly I think we should not let perfect be the enemy of
> (very) good ;)

We do not support this yet, but once we have nested virtualization, it
won't be that odd to have a bridge or bond in the guest. I know that we
already have users with in-guest vlan devices.

I think that the api should accomodate these configurations - even if we
do not report them right away. The guest agent already reports (some) of
the information:

> The Guest Agent reports the vNic details:
> 
>     IP addresses (both IPv4 and IPv6).
>     vNic internal name 

Actually, the guest agent reports all in-guest network device. vNics (and bonds
and vlans) included.
> 
> The retrieved information by the Guest Agent should be reported to the ovirt-engine and to be viewed by its client
> Today only the IPv4 addresses are reported to the User, kept on VM level. This feature will maintain the information on vNic level.

I think we should report the information on the vNic level only when we
can. If we have a vlan device, which we do not know how tie to a
specific vNic, we'd better report its IP address on the VM level.

It might be worthwhile to note that we should (try to) correlate Engine
idea of a vNic with the guest agent report, according to the mac address.
The guest can try to fool us by changing the mac address, but that's
true for every bit of info coming from the agent.

Dan.