libvirt users - Feb 2020 - Re: Possible to use OVN networking and virtio simultaneously in the same VM?

On Fri, Feb 14, 2020 at 8:05 PM Andre Goree <agoree@staff.atlantic.net>
wrote:
> I wanted to know if it's possible to use OVN networking and virtio
> simultaneously in the same VM?  Or am I wasting my time trying to get it to
> work?
>
>
In  oVirt 4.x I was able to do it and also to intermix normal vnic and OVN
based vnic.
I needed to reproduced a problem I had in a physical Red Hat Cluster. So i
"cloned" the physical nodes to oVirt VMs and the vnic of the
intracluster
network of this virtual RedHat cluster was put on OVN, while the production
vnic was on a normal lan.
Both with virtio as the network type and the second with openvswitch
virtualport.
I just simulate it on a RHV 4.3.7 env and it starts ok
the snippet of the dynamic xml definition that RHV creates is this one
(note some RHV related parameters not pertinent to your env I think).
Note also that on OVN based nics I often put 1442 as the mtu size.

    <interface type='bridge'>
      <mac address='00:1a:4a:16:01:1d'/>
      <source bridge='vlan65'/>
      <target dev='vnet0'/>
      <model type='virtio'/>
      <driver name='vhost' queues='2'/>
      <filterref filter='vdsm-no-mac-spoofing'/>
      <link state='down'/>
      <mtu size='1500'/>
      <alias name='ua-8ccec0e9-c32d-4021-8a06-3d24280536b8'/>
      <address type='pci' domain='0x0000' bus='0x00'
slot='0x03'
function='0x0'/>
    </interface>
    <interface type='bridge'>
      <mac address='00:1a:4a:16:01:20'/>
      <source bridge='br-int'/>
      <virtualport type='openvswitch'>
        <parameters
interfaceid='9c0927a8-2256-44f3-b089-0e8923055747'/>
      </virtualport>
      <target dev='vnet1'/>
      <model type='virtio'/>
      <driver name='vhost' queues='2'/>
      <link state='up'/>
      <mtu size='1442'/>
      <alias name='ua-ea95c1fe-b226-4a64-ad30-ee5cb2da08ca'/>
      <address type='pci' domain='0x0000' bus='0x00'
slot='0x06'
function='0x0'/>
    </interface>

On this particular environment RHV provides these packages:

ovn2.11-2.11.1-8.el7fdp.x86_64
openvswitch2.11-2.11.0-26.el7fdp.x86_64
libvirt-4.5.0-23.el7_7.3.x86_64
qemu-kvm-rhev-2.12.0-33.el7_7.4.x86_64

Which kind of errors do you get in term of functionality? no connection
between two VMs on the same OVN networking subnet?
How did you configure OVN? I ask because in oVirt/RHV now you do it from a
general setup command and then through web gui admin, not manually
Your OS?
HIH,
Gianluca