Automated removal of empty bridges has been disabled to fix a race condition between the Compute (nova) and Networking (neutron) services. Previously, it was possible for a bridge to be deleted during the time when the only instance using it was rebooted.
Use this script to remove empty bridges on compute nodes by running the following command:
Do not use this tool when creating or migrating an instance as it throws an error when the bridge does not exist.
Using this script can still trigger the original race condition. Only run this script if you have evacuated all instances off a compute node and you want to clean up the bridges. In addition to evacuating all instances, you should fence off the compute node where you are going to run this script so new instances do not get scheduled on it.