device br0 already exists

Here’s how you solve either of the following errors on Ubuntu (and possibly Debian):

device br0 already exists; can't create bridge with the same name
device eth0 is already a member of a bridge; can't enslave it to bridge br1.

Removing the device specs from /etc/network/interfaces and restarting the network doesn’t actually remove the device if already active. You need to do it manually.

List the active devices:

ifconfig | more

And then do this to any that you don’t want there, such as br0, eth0, eth1, etc:

ifconfig br0 down
# and so on

This deactivates the device. At this point you’ll need to restart the network layer twice:

sudo /etc/init.d/networking restart
sudo /etc/init.d/networking restart

And you should be sitting pretty. On some systems, networking is known as network, as in:

sudo /etc/init.d/network restart
sudo /etc/init.d/network restart

Published by

Leons Petrazickis

I'm a full-stack developer at IBM Digital Business Group. I do Ruby, Node, Python, Hadoop, Spark, as well as web scale devops with Docker and Terraform. My opinions are my own.