[lxc-users] Help with Ubuntu Networking

[Fajar A. Nugraha]

On Sat, May 10, 2014 at 11:15 AM, CDR <venefax at gmail.com> wrote:
> This is not related directly to LXC, but I know that some people here
> work for Canonical, and before I get back to Fedora, I need to ask a
> question.
> I already Googled it and believe me, nobody has an answer, all are
> more questions than responses.
>
> I need to bring up 12 empty bridges, that is, bridges that have no
> interface and no IP.

You're not looking hard enough
https://www.google.com/search?q=ubuntu+bridge+without+ip+address
http://wiki.1tux.org/wiki/Ubuntu/Bridge

> In "interfaces", I have something like this
> auto br0
> iface br0 inet manual
> pre-up echo "Starting $IFACE"
> pre-up ip addr flush dev $IFACE
> pre-up ip link set $IFACE down
> post-down ip link set $IFACE down
>
> How do I create the bridge?
> in /etc/rc.local I execute brctl addbr br0
>
> There is nothing wrong with this , right?

Yes, there is.

On trusty the error message is clearer: Cannot find device "br0"

Basically ubuntu does not know "br2" is a bridge. You need (at the
very least) "bridge_ports none". My example if the wiki uses dummy
interface for the bridge.


Here's another example (again, on trusty):

(snippet from /etc/network/interface)
auto fancy-if-name
iface fancy-if-name inet static
        bridge_ports none
        address 0.0.0.0
        netmask 0.0.0.0

# brctl show fancy-if-name
bridge name bridge id STP enabled interfaces
fancy-if-name 8000.000000000000 no

# ifconfig fancy-if-name
fancy-if-name Link encap:Ethernet  HWaddr 02:aa:fd:37:bb:a5
          inet6 addr: fe80::aa:fdff:fe37:bba5/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:23 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:0 (0.0 B)  TX bytes:3809 (3.8 KB)


> note: I will allow access to the box anybody whose email says @canonical.

While you are entitled to give access to whoever you want, that note
in my oppinion is a very selfish one. You're basically saying:
- you want support from someone in canonical
- you don't want to pay for the support
- you don't trust anyone else in the list

The open source community (including lxc) does not only consist of
paid developers that work in a company. More often, a quick and useful
answer will come from a fellow user.

-- 
Fajar