[Lxc-users] [Spam-Wahrscheinlichkeit=45] lxcbr0 MAC addr issue

[Jäkel, Guido]

Dear Hans,

this is a FAQ here but -- as you already found -- not basically caused by LXC. The software bridge will always choose the lowest MAC of the attached devices or hold an explicit assigned (from the set of currently assigned devices) as long as possible. In your case you either may set the MAC of the outgoing NIC or set the MAC of the veth's from a range which is above common hardware. There are more or less reserved ranges used for this by us here and in similar projects. 

Guido

>-----Original Message-----
>From: Hans Feldt [mailto:hans.feldt at ericsson.com]
>Sent: Wednesday, June 05, 2013 8:23 AM
>To: lxc-users at lists.sourceforge.net
>Subject: [Spam-Wahrscheinlichkeit=45][Lxc-users] lxcbr0 MAC addr issue
>
>
>It is a fact that the bridge takes the lowest MAC address from the attached ports for the host port. See for example
>http://backreference.org/2010/07/28/linux-bridge-mac-addresses-and-dynamic-ports/
>
>Thus if a container is restarted, the host port can potentially change its MAC address and containers will have a stale ARP cache. This of
>course causes problem for communication container->host.
>
>Tested the workaround mentioned in the link but then I got problem with network manager on a later Ubuntu version. Then I tried using a
>dummy container and reusing its MAC addr for the host port. Works but...
>
>Now my question, could not lxc (at boot) setup a fixed MAC addr for the host port?
>
>Thanks,
>Hans