Re: Connection fail-over

[Dan Williams <dcbw redhat com>]

On Wed, 2017-04-12 at 10:44 -0500, Alex Ferm wrote:
> I don't think there is a built-in fail-over mechanism, but you should
> be 
> able to write a dispatcher script to handle it. 
> https://developer.gnome.org/NetworkManager/1.6/NetworkManager.html

Yeah, that was the general idea.  There are unfortunately a lot of ways
to say "this connection has failed" (IP packet loss? physical link
error rate? link speed degredation? latency spikes?) and encoding them
all into NetworkManager isn't a flexible solution.  So that gets punted
to dispatcher scripts if you need more detailed metrics to make the
decision of "this connection has failed".

Also important to distinguish between fail-over on the same device, or
fail-over between devices.  NM has some support for both, including
priorities for the default route across all devices, and for
connections for a given device.  I'd think many scenarios could be
handled through dispatcher scripts.

That all said, if there's something missing to help support dispatcher
script-based failover, or there is something that so many people use
that it might as well be included in NM, please let us know!

Dan