bridge device is missing

[Timur Nitt]

Ubuntu 18.04: Since last dist-upgrade of the bridge-utils (2018-03-21) the bridge netwok device 'br0' is missing. A 'ls /sys/class/net' prints the devices 'enp3s0 lo lxcbr0 virbr0 virbr0-nic' only.

[Timur Nitt (tnitt)]

And the syslog bloats:
...
Mar 21 11:06:26 pyrimea org.mate.panel.applet.NetspeedAppletFactory[2240]: glibtop(c=2702): [WARNING] Failed to open "/sys/class/net/br0/statistics/rx_bytes": Datei oder Verzeichnis nicht gefunden
Mar 21 11:06:26 pyrimea org.mate.panel.applet.NetspeedAppletFactory[2240]: glibtop(c=2702): [WARNING] Failed to open "/sys/class/net/br0/statistics/tx_bytes": Datei oder Verzeichnis nicht gefunden
Mar 21 11:06:26 pyrimea org.mate.panel.applet.NetspeedAppletFactory[2240]: glibtop(c=2702): [WARNING] Failed to open "/sys/class/net/br0/statistics/rx_errors": Datei oder Verzeichnis nicht gefunden
Mar 21 11:06:26 pyrimea org.mate.panel.applet.NetspeedAppletFactory[2240]: glibtop(c=2702): [WARNING] Failed to open "/sys/class/net/br0/statistics/tx_errors": Datei oder Verzeichnis nicht gefunden
Mar 21 11:06:26 pyrimea org.mate.panel.applet.NetspeedAppletFactory[2240]: glibtop(c=2702): [WARNING] Failed to open "/sys/class/net/br0/statistics/collisions": Datei oder Verzeichnis nicht gefunden
Mar 21 11:06:27 pyrimea org.mate.panel.applet.NetspeedAppletFactory[2240]: glibtop(c=2702): [WARNING] Failed to open "/sys/class/net/br0/statistics/rx_packets": Datei oder Verzeichnis nicht gefunden
Mar 21 11:06:27 pyrimea org.mate.panel.applet.NetspeedAppletFactory[2240]: glibtop(c=2702): [WARNING] Failed to open "/sys/class/net/br0/statistics/tx_packets": Datei oder Verzeichnis nicht gefunden
Mar 21 11:06:27 pyrimea org.mate.panel.applet.NetspeedAppletFactory[2240]: glibtop(c=2702): [WARNING] Failed to open "/sys/class/net/br0/statistics/rx_bytes": Datei oder Verzeichnis nicht gefunden
Mar 21 11:06:27 pyrimea org.mate.panel.applet.NetspeedAppletFactory[2240]: glibtop(c=2702): [WARNING] Failed to open "/sys/class/net/br0/statistics/tx_bytes": Datei oder Verzeichnis nicht gefunden
Mar 21 11:06:27 pyrimea org.mate.panel.applet.NetspeedAppletFactory[2240]: glibtop(c=2702): [WARNING] Failed to open "/sys/class/net/br0/statistics/rx_errors": Datei oder Verzeichnis nicht gefunden
Mar 21 11:06:27 pyrimea org.mate.panel.applet.NetspeedAppletFactory[2240]: glibtop(c=2702): [WARNING] Failed to open "/sys/class/net/br0/statistics/tx_errors": Datei oder Verzeichnis nicht gefunden
Mar 21 11:06:27 pyrimea org.mate.panel.applet.NetspeedAppletFactory[2240]: glibtop(c=2702): [WARNING] Failed to open "/sys/class/net/br0/statistics/collisions": Datei oder Verzeichnis nicht gefunden
...

[Timur Nitt (tnitt)]

And there's no way to downgrade from 1.5-15ubuntu1 to 1.5-9ubuntu2.

[Timur Nitt (tnitt)]

A manual 'brctl addbr br0' brings up the bridge interface. Doing this at boot time would be better.

[Marco (cardmaker)]

I have the same problem after a dist-upgrade on Ubuntu 18.04 server. All my bridges are not found anymore. There was an update from .5-9ubuntu2 to 1.5-15ubuntu1, however downgrading does NOT fix the problem. Manually setting the bridges works, but this is not a permanent solution.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Timur Nitt (tnitt)]

I've installed a new Ubuntu 18.04 system with the bridge-utils on 2018-03-27, based on mini.iso, located here: http://archive.ubuntu.com/ubuntu/dists/bionic/main/installer-amd64/current/images/netboot/mini.iso (ISO file release date 2018-03-15). The difference of my workstation installation before (Mate system), I used the KDE Plasma desktop now. The script located in the attachment shows the installation flow of my favourite system.
Now the bridge is working. I don't know the actual background of this behavior why this didn't work before. Maybe there's another (or a new) package which handles the bridge interface control additionally.

[Marco (cardmaker)]

Re-installing Ubuntu 18.04 server solved the issue.

[Andreas Hasenack (ahasenack)]

Thanks, it must have been something during the development of the release.

18.04, when fresh installed, will use netplan for networking. You can find configuration examples, including for bridging, in https://netplan.io/examples