From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stephen Hemminger <stephen@networkplumber.org>
Subject: Re: [RFC PATCH v3 0/3] Enable virtio_net to act as a backup for a
	passthru device
Date: Mon, 26 Feb 2018 17:02:18 -0800
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Cc: "Duyck, Alexander H" <alexander.h.duyck@intel.com>,
	virtio-dev@lists.oasis-open.org, "Michael S. Tsirkin" <mst@redhat.com>,
	Jakub Kicinski <kubakici@wp.pl>, "Samudrala,
	Sridhar" <sridhar.samudrala@intel.com>,
	Alexander Duyck <alexander.duyck@gmail.com>,
	virtualization@lists.linux-foundation.org,
	Siwei Liu <loseweigh@gmail.com>, Netdev <netdev@vger.kernel.org>,
	David Miller <davem@davemloft.net>
To: Jiri Pirko <jiri@resnulli.us>
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On Mon, 26 Feb 2018 08:19:24 +0100
Jiri Pirko <jiri@resnulli.us> wrote:

> Sat, Feb 24, 2018 at 12:59:04AM CET, stephen@networkplumber.org wrote:
> >On Thu, 22 Feb 2018 13:30:12 -0800
> >Alexander Duyck <alexander.duyck@gmail.com> wrote:
> >  
> >> > Again, I undertand your motivation. Yet I don't like your solution.
> >> > But if the decision is made to do this in-driver bonding. I would like
> >> > to see it baing done some generic way:
> >> > 1) share the same "in-driver bonding core" code with netvsc
> >> >    put to net/core.
> >> > 2) the "in-driver bonding core" will strictly limit the functionality,
> >> >    like active-backup mode only, one vf, one backup, vf netdev type
> >> >    check (so noone could enslave a tap or anything else)
> >> > If user would need something more, he should employ team/bond.    
> >
> >Sharing would be good, but netvsc world would really like to only have
> >one visible network device.  
> 
> Why do you mind? All would be the same, there would be just another
> netdevice unused by the vm user (same as the vf netdev).
> 

I mind because our requirement is no changes to userspace.
No special udev rules, no bonding script, no setup.

Things like cloudinit running on current distro's expect to see a single
eth0.  The VF device show up can also be an issue because distro's have
stupid rules like Network Manager trying to start DHCP on every interface.
We deal with that now by doing stuff like udev rules to get it to stop
but that is still causing user errors.