Bridges to be used on compute nodes are showing up created on the controller after deployment in Red Hat OpenStack Platform 10

Issue

Bridges to be used on compute nodes are showing up created on the controller after deployment in Red Hat OpenStack Platform 10

Bridges on controllers get automatically created although they are not configured in the nic-config .yaml files. In the following article, br-test1 / br-test2 are examples of those bridges.

On the controller:

ovs-vsctl -t 5 show
(...)
    Bridge br-test1
        Controller "tcp:127.0.0.1:6633"
            is_connected: true
        fail_mode: secure
        Port phy-br-test1
            Interface phy-br-test1
                type: patch
                options: {peer=int-br-test1}
        Port br-test1
            Interface br-test1
                type: internal
    Bridge br-int
 (...)
    Bridge br-test2
        Controller "tcp:127.0.0.1:6633"
            is_connected: true
        fail_mode: secure
        Port br-test2
            Interface br-test2
                type: internal
        Port phy-br-test2
            Interface phy-br-test2
                type: patch
                options: {peer=int-br-test2}
 (...)
    ovs_version: "2.6.1"

Indeed, these bridges are not configured anywhere in the templates

cd /home/stack/templates/nic-configs
grep ovs_bridge * -A1
--
controller.yaml:              type: ovs_bridge
controller.yaml-              name: {get_input: bridge_name}

These are only defined in the bridge mappings:

grep br-test etc/neutron/* -R
etc/neutron/plugins/ml2/openvswitch_agent.ini:bridge_mappings =dpdk1:br-test2,dpdk2:br-test1