Re: Add support for VETH devices in Network Manager (required to run NetworkManager in LXC containers)

[Pavel Simerda <psimerda redhat com>]

> I'm using LXC containers to run our network test suites in Ubuntu and
> while adding Network Manager support to my tests, I noticed that
> Network
> Manager doesn't know what a veth device is and was simply ignoring my
> ethX devices.

I wonder if they should be labeled like that when they are basically
just (virtual) ethernet devices. The patch looks ok.

> The attached patch adds an extra interface type for veth devices and
> updates the logic in the udev event code so that if a veth device is
> detected and that its name doesn't start by "veth" it'll be
> considered as a regular network interface with "veth" as the driver.
> 
> The veth devices behave like a regular physical device, support the
> ethtool calls and any regular call you might do, but they aren't tied
> to physical device.

Does it support all sorts of VLAN and bridging stuff? I remember
OpenVZ's implementation didn't support these features well.

> These devices are used by containers as the point to point link
> between
> the host and the container. The container side of it is usually
> called
> "ethX" in the container network namespace, the host side of it is
> usually called "vethXXXXX" (randomly generated suffix) and is bridged
> on
> the host side.
> 
> The patch ignores the host side of the veth pairs as these are
> usually
> bridged or used by some other tool that won't like NM interfering
> with
> them. Doing that string check isn't particularly pretty but it's the
> easiest way I found to deal with the problem.

I guess it would be better not to include this exception at all and to
actually manage these with NetworkManager. But this is for further
discussion. 

> I tested the patch on an Ubuntu 12.10 system
> (0.9.4.0+git201206081144.2efeac8 + Ubuntu patches) running the same
> NM
> in both the host and the container. As expected, the container side
> properly started handling the interface and the host side ignored it
> completely.
> 
> 
> Please keep me Cced on any reply as I'm not subscribed to this
> mailing-list.

Consider moving this to bugzilla.

Cheers,

Pavel