lxcbr0 missing after starting lxc-net.service

[Ryan Harper]

1. % lsb_release -rd
Description: Ubuntu Wily Werewolf (development branch)
Release: 15.10

2. % apt-cache policy lxc
lxc:
  Installed: 1.1.2-0ubuntu3
  Candidate: 1.1.2-0ubuntu3
  Version table:
 *** 1.1.2-0ubuntu3 0
        500 http://us.archive.ubuntu.com/ubuntu/ wily/main amd64 Packages
        100 /var/lib/dpkg/status

3. sudo systemctl restart lxc-net.service should bring up lxcbr0 bridge device

4. lxcbr0 device is not present after starting/restarting lxc-net.service

(kriek) ~ % sudo systemctl restart lxc-net.service
(kriek) ~ % sudo systemctl status -l lxc-net.service
● lxc-net.service - LXC network bridge setup
   Loaded: loaded (/lib/systemd/system/lxc-net.service; enabled; vendor preset: enabled)
   Active: active (exited) since Tue 2015-07-07 13:33:15 CDT; 3s ago
  Process: 1764 ExecStop=/usr/lib/x86_64-linux-gnu/lxc/lxc-net stop (code=exited, status=0/SUCCESS)
  Process: 1769 ExecStart=/usr/lib/x86_64-linux-gnu/lxc/lxc-net start (code=exited, status=0/SUCCESS)
 Main PID: 1769 (code=exited, status=0/SUCCESS)

Jul 07 13:33:15 kriek systemd[1]: Starting LXC network bridge setup...
Jul 07 13:33:15 kriek lxc-net[1769]: dnsmasq: cannot read /etc/dnsmasq.conf: No such file or directory
Jul 07 13:33:15 kriek systemd[1]: Started LXC network bridge setup.
(kriek) ~ % brctl show
bridge name bridge id STP enabled interfaces
virbr0 8000.5254005821b0 yes virbr0-nic
(kriek) ~ % ifconfig lxcbr0
lxcbr0: error fetching interface information: Device not found

My wily system does not have a dnsmasq.conf and without one which includes the conf-dir = /etc/dnsmasq.d
directive, then lxc-net does not come up.

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: lxc 1.1.2-0ubuntu3
ProcVersionSignature: Ubuntu 4.0.0-4.6-generic 4.0.7
Uname: Linux 4.0.0-4-generic x86_64
ApportVersion: 2.17.3-0ubuntu4
Architecture: amd64
Date: Tue Jul 7 13:35:41 2015
InstallationDate: Installed on 2015-05-10 (57 days ago)
InstallationMedia: Ubuntu-Server 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.3)
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: lxc
UpgradeStatus: No upgrade log present (probably fresh install)
defaults.conf:
 lxc.network.type = veth
 lxc.network.link = lxcbr0
 lxc.network.flags = up
 lxc.network.hwaddr = 00:16:3e:xx:xx:xx

[Pau Iranzo (paugnu)]

Hi,

I've run into the same problem and haven't found any useful answers so far. However, doing exactly the opposite explained here:
https://community.flockport.com/topic/25/lxc-net-fails-to-create-bridge-on-ubuntu-server-14-04-1

It works for me.

So, temporary solution:

$ vim /etc/dnsmasq.d/lxc

Comment all lines:

# Tell any system-wide dnsmasq instance to make sure to bind to interfaces
# instead of listening on 0.0.0.0
# WARNING: changes to this file will get lost if lxc is removed.
#bind-interfaces
#except-interface=lxcbr0

So the file ends up doing nothing. After restarting the system, I get my lxcbr0 back and I can access to my lxc machines again.

[Serge Hallyn (serge-hallyn)]

@paugnu

which ubuntu release are you on and what is your dnsmasq version? (dpkg -l dnsmasq) Do you have bind installed?

Does creating /etc/dnsmasq.conf fix without having to clear out /etc/dnsmasq.d/lxc ?

[Launchpad Janitor (janitor)]

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