Disable autostart of lxcbr0 on Ubuntu 16.04 xenial

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Published on April 22nd 2016 - Listed in Linux LXC


One of the major changes on Ubuntu 16.04 (Xenial) is the integration of LXD using LXC 2.0 in the background.
Although I love LXC, I'm kind of annoyed by the fact, that it comes as part of the "base" installation. If I want LXD/LXC, I install it manually. 

Because LXD is now installed by default, the LXC bridge (lxcbr0) is now started automatically:

root@xenial:~# ifconfig
ens160    Link encap:Ethernet  HWaddr 00:50:56:99:37:c4 
          inet addr:10.10.10.10  Bcast:10.10.10.255  Mask:255.255.255.0
          inet6 addr: fe80::250:56ff:fe99:37c4/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:918 errors:0 dropped:1 overruns:0 frame:0
          TX packets:441 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:78692 (78.6 KB)  TX bytes:92428 (92.4 KB)

lo        Link encap:Local Loopback 
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

lxcbr0    Link encap:Ethernet  HWaddr 86:dc:ff:84:80:20 
          inet addr:10.0.3.1  Bcast:0.0.0.0  Mask:255.255.255.0
          inet6 addr: fe80::84dc:ffff:fe84:8020/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:7 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:0 (0.0 B)  TX bytes:570 (570.0 B)

To disable the automatic start of the virtual bridge lxcbr0, adapt /etc/default/lxc-net and set USE_LXC_BRIDGE to false:

root@xenial:~# sed -i "/USE_LXC_BRIDGE/s/true/false/g" /etc/default/lxc-net

This disables the automatic start of the virtual bridge at boot time.

To turn off and delete the bridge during runtime:

root@xenial:~# ifconfig lxcbr0 down
root@xenial:~# brctl delbr lxcbr0


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Comments (newest first)

Fjor from wrote on May 20th, 2016:

I couldn't disable the bridge at start using the /etc/default config. In systemd those configs are deprecated. I resolved the issue stopping LXD services in /etc/rc.local with:

service lxd stop

service lxcfs stop

The bridge will be disabled too.