Re: No more IPv4 address after boot up since NM 0.9.10

[Dan Williams <dcbw redhat com>]

On Mon, 2015-03-02 at 22:03 +0100, Frederik Himpe wrote:
> On ma, 2015-03-02 at 14:22 -0600, Dan Williams wrote:
>
> > > I also have netconsole activated via this line in a file
> > > in /etc/modprobe.d:
> > >
> > > options netconsole netconsole=6666 192 168 5 205/eth0,6666 192 168 5 128/24:77:03:f0:16:64
> > >
> > > Could this be related in some way?
> >
> > Yes, that might well bring the interface into IFF_UP state before NM
> > starts, at which point the interface might already be assigned both IPv4
> > and IPv6 LL addresses before NM starts, leading to the behavior you see.
>
> OK, I removed all this netconsole stuff, rebuild my initrd and deleted
> the eth0 network connection in NM, and at the next reboot, everything
> was working.
>
> I am not sure whether this is a really satisfying solution though: what
> if I would want to debug potential kernel errors during boot, then NM
> will cause your these kind of troubles?

Well, I don't think NM is causing any kind of troubles at all, it's just
noticing that the interface is configured already when it starts, and
tries very hard not to mess with the interface.  The kernel is setting
the interface IFF_UP, and that causes the kernel to assign an IPv6LL
address to the interface, and then start IPv6 SLAAC on it.  That results
in the interface receiving an global IPv6 address, and that's what NM is
noticing and not touching, because the interface has already been
configured...

NetworkManager has no idea whether the administrator of the system
expects the interface to remain configured that way or not, and NM
reconfiguring the interface could (for example) badly break bootup when
your filesystem is on the network.

One option would be to put something like "ip addr flush dev eth0" in
your rc.local if you know you don't care about the kernel configuration
after bootup...

Dan