VM 中的 Open vSwitch 网桥不通过端口发送流量

Question

I'm trying to run the Pike release OpenStack Kolla with Open vSwitch in a VM as a part of a test / dev environment. I feel like I am missing something obvious, but I just figure it out.

In the VM, Open vSwitch in a docker container.

The version in both the VM and host is:

openvswitch-switch/xenial-updates,now 2.8.1-0ubuntu0.17.10.2~cloud0 amd64 [installed] I create the bridge using:

ovs-vsctl add-br br-ex ovs-vsctl add-port br-ex ens3 ip addr flush ens3

I run the same commands on a bare-metal server and it works just fine. In the VM, the MAC address for br-ex doesn't match the MAC of the NIC. They MACs match on the bare-metal instance.

If I delete the bridge ovs-vsctl del-br then traffic flows normally through the ens3 interface.

While the bridge is active, ovs-system is listed as a capability on the nic.

ovs-vsctl show
<snip>
    Bridge br-ex
        Port "ens3"
            Interface "ens3"
        Port br-ex
            Interface br-ex
                type: internal

The main difference that I can see is that the ens3 in the VM is using the.net-virtio driver. I don't see why this would make a difference.

Ubuntu 16.04.4 is the operating system for both the host and vm. Using a typical KVM, QUEMU, and libvirt setup compute nodes.

Answer 1

I still don't know why this behaves differently in a VM than on bare-metal. Setting the MAC on the bridge to match the network interface resolved this issue.

ovs-vsctl add-br br-ex -- set bridge br-ex other-config:hwaddr=\"ff:ff:ff:ff:ff:ff\"'

Answer 2

Thanks a lot for your clarification, I was getting crazy myself. When you create the bridge it assigns a different MAC address than the one that the ens3 has and from that moment the dhclient wont work, but following your advice, and assigning the ens3 MAC to the bridge, dhclient worked and I was able to have the traffic going through the bridge to the outside world.

sudo ovs-vsctl add-br br77 -- set bridge br77 other_config:hwaddr=ff:ff:ff:ff:ff:ff