Comment 0 for bug 1105488

The linuxbridge agent currently creates a bridge for each physical network used as a flat network, moving any existing IP address from the interface to the newly created bridge. This is very helpful in some cases, but there are other cases where the ability to use a pre-existing bridge is needed. For instance, the same physical network might need to be bridged for other purposes, or the agent moving the system's IP might not be desired.

I suggest we add a physical_bridge_mappings configuration variable, similar to that used by the openvswitch agent, alongside the current physical_interface_mappings variable. When a bridge for a flat network is needed, the bridge mappings would be checked first. If a bridge mapping for the physical network exists, it would be used. If not, the interface mapping would be used and a bridge for the interface would be created automatically. Sub-interfaces and bridges for VLAN networks would continue to work as they do now, created by the agent using the interface mappings.