Linux Virtualization - Mar 2019 - [RFC PATCH net-next] failover: allow name change on IFF_UP slave interfaces

On Tue, 5 Mar 2019 11:19:32 -0800
si-wei liu <si-wei.liu at oracle.com> wrote:
> > I have a vague idea: would it work to *not* set
> > IFF_UP on slave devices at all?  
> Hmm, I ever thought about this option, and it appears this solution is 
> more invasive than required to convert existing scripts, despite the 
> controversy of introducing internal netdev state to differentiate user 
> visible state. Either we disallow slave to be brought up by user, or to 
> not set IFF_UP flag but instead use the internal one, could end up with 
> substantial behavioral change that breaks scripts. Consider any admin 
> script that does `ip link set dev ... up' successfully just assumes the
> link is up and subsequent operation can be done as usual. While it *may* 
> work for dracut (yet to be verified), I'm a bit concerned that there
are
> more scripts to be converted than those that don't follow volatile 
> failover slave names. It's technically doable, but may not worth the 
> effort (in terms of porting existing scripts/apps).
> 
> Thanks
> -Siwei
Won't work for most devices.  Many devices turn off PHY and link layer
if not IFF_UP