how does kolla configure br-ex?

asked 2017-12-06 17:41:18 -0600

jcorkey gravatar image

I deployed using kolla/kolla-ansible 5.0.0 on one compute node and one control node.

How does kolla configure the br-ex bridge??? After deploying, I can see that there are three bridges br-int, br-tun, and br-ex by running ovs-vsctl show

But where is the ifcfg-br-ex files?? Do I need to add the ifcfg-br-ex? I am getting confused with things since openstack services are running within containers,. I am having uses with pinging the floating IP's and router in openstack and I think it is an issue with the br-ex.

I have added all the correct security groups so I know thats NOT the problem.

So I am trying to understand how much I am responsible for configuring the br-ex or does kolla do all that for me?

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check /etc/kolla/neutron-openvswitch-agent/ .in this file there is ovs tag which defines bridge mapping. each neutron service has ml2 file in is configured by kolla itself in network node

akarki gravatar imageakarki ( 2017-12-06 23:01:16 -0600 )edit

Ok thanks. I’m still a little confused though. I see br-int, br-tun, br-ex when I run the ovs-vsctl show in the openvswitchd container and it all looks correct but when I run nmcli d or ip a br-int, br-tun, br-ex say they are unmanaged. Like in the output in the comment below. Why is that?

jcorkey gravatar imagejcorkey ( 2017-12-06 23:16:58 -0600 )edit

br-ex openvswitch unmanaged br-int openvswitch unmanaged br-tun openvswitch unmanaged ovs-system openvswitch unmanaged

jcorkey gravatar imagejcorkey ( 2017-12-06 23:27:03 -0600 )edit

br-ex br-int and br-tun are supposed to have no ip address and are in down state after deployement.

akarki gravatar imageakarki ( 2017-12-06 23:32:33 -0600 )edit

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answered 2017-12-07 08:51:06 -0600


  • Kolla reads neutron_external_interface variable.
  • The create a bridge br-ex in OVS (not the host/hypervisor)
  • Lastly attach the interface into the bridge.,#L21

The host does not need configuration file for the bridge nor the interface manually attached as OVSport in the bridge. Only need a interface UP with no IP address associated to it. When a network is created, the traffic will flow through:

bridge (br-ex) -> physical interface (eth2) -> external router/switch outside openstack (neutron gateway)


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Eduardo, this is my globals.yml file ( My controller (Centos) has two nics: eth0, eth1. eth1 has an IP address. When I create an external network, I'm not able to reach it. What is the problem then? According to your answer, I shouldn't do anything else.

sacha-m gravatar imagesacha-m ( 2018-01-28 16:39:30 -0600 )edit

And here are my interfaces:

sacha-m gravatar imagesacha-m ( 2018-01-28 16:41:58 -0600 )edit

Also, in is the output of "docker exec openvswitch_vswitchd ovs-vsctl list-br", "docker exec openvswitch_vswitchd ovs-vsctl list-ports br-ex", "", "" and "cat /etc/sysconfig/network-scripts/ifcfg-eth1".

sacha-m gravatar imagesacha-m ( 2018-01-28 19:58:33 -0600 )edit

Issue is attaching tunnel_interface to eth1 which is also external interface, tunnel interface is where vxlan tunnels for private networks flow. Also external interface not need IP address. If not have a dedicated interface for tunnels use api_interface

Eduardo Gonzalez gravatar imageEduardo Gonzalez ( 2018-01-29 01:15:48 -0600 )edit

I changed cluster_interface from eth1 to eth0, unset the IP in eth1, redeploy and worked. Thanks!

sacha-m gravatar imagesacha-m ( 2018-01-29 09:17:16 -0600 )edit

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Asked: 2017-12-06 17:41:18 -0600

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Last updated: Dec 07 '17