sudo systemctl stop libvirtd.service #Systemd OS


Then,take down the bridge.


sudo ifconfig virbr0 down #centos6 centos7
sudo ip link set dev virbr0 down #centos7


Finally,remove this bridge.


sudo brctl delbr virbr0


Additionally. If libvirtd.service is restarted. the bridge will created automatically. So you better disable this service.


sudo systemctl disable libvirtd.service