Re: veth won't be configured in libvirt managed LXC container

[Gene Czarcinski <gczarcinski gmail com>]

On 10/19/2014 09:53 AM, Lubomir Rintel wrote:
> On Sat, 2014-10-18 at 16:00 -0400, Gene Czarcinski wrote:
> > On 10/16/2014 07:08 AM, Lubomir Rintel wrote:
> > > Hi,
> > >
> > > currently it is impossible to get useful network configuration for LXC
> > > containers on boot. (At least if they're managed via libvirt; I have no
> > > idea if anything is different with native LXC tooling). They're supposed
> > > to obtain their configuration via DHCP, but instead connection is assumed.
> > > Firstly because there's an IPv6 local link address that (I think) gets
> > > assigned when libvirt ups the interface and secondly because it's a
> > > software link.
> > >
> > > Why do we assume connection on all software links? Virtual ethernet devices
> > > are supposed to behave much like ordinary ethernet devices; they have
> > > carrier detection, etc.
> > >
> > > I'm following up with the patches that resolve the problem for me, but
> > > I'm not quite sure about the special case for veth.
> > >
> > > Thoughts?
> > This may be related to a problem in libvirt-sandbox (Secure Containers):
> > https://www.redhat.com/archives/libvir-list/2014-September/msg00540.html
> Does that mean lxc (or libvirt or whatever) is supposed to configure the
> interface before spawning the container? In that case it would indeed
> make sense for NM to assume the connection.
My only experience is with Secure Containers created by 
virt-sandbox-service of the libvirt-sandbox package.  Without my 
patches, you can successfully create a virtual NIC with either static or 
dhcp addresses.  With dhcp, dhclient needs to be started. Without the 
patches, dhcp does not work.  I do not know if this problem applies 
generally to containers or not.

Although not a secure container, the following does work:
      virt-sandbox  -c  lxc:///  -N dhcp,source=default  /bin/sh

I has some problem with chrony but, when you get in, ip addr will show 
eth0 with an address

Now, through all of this, NetworkManager is going nuts trying to get 
dhclient to work with vnetN but it never succeeds.

Could someone who understands what NetworkManager "should" be doing and 
why explain.  It is certainly not clear to me that NetworkManager should 
be doing anything!

Gene
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