[libvirt] Libvirt, nwfilter, openvswitch

[Daniel P. Berrange]

On Wed, Nov 06, 2013 at 02:44:57PM +0100, Jan De Landtsheer wrote:
> Hello,
> I _was_ trying to set up an nwfilter for our networking set-up with VXLAN
> and openvswitch, where we use VXLAN as carrier for separate networks
> (unlike OpenStack gre-tunnels).
> 
> But with OVS, ebtables do not work, and the basic setup of nwfilter rules
> are based on this premise... or so I understand...
> 
> Now..
> Is there a way to define nwfilter rules _without_ ebtables ?
> 
> What I would like to do is quite simple (block out dhcp{4,6} services from
> VM's, and ipv6 router advertisements )

There's no support for nwfilter at all when using openvswitch, due to
the kernel limitations you mention. The (disgusting) way openstack deals
with this is to create a traditional bridge  per vm so you have


   phys nic <-> openvswitch
                          \--->  vm bridge <-> vm tap dev
                          \--->  vm bridge <-> vm tap dev
                          \--->  vm bridge <-> vm tap dev

Daniel
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