[ovs-discuss] Temporary loss of network connection during addition of a port to bridge

[Ben Pfaff]

[getting back to email after a month of craziness]

On Fri, Apr 24, 2015 at 02:38:37AM +0100, Mark Clarkson wrote:
> On 24/04/15 01:38, Ben Pfaff wrote:
> >On Fri, Apr 24, 2015 at 01:01:07AM +0100, Mark Clarkson wrote:
> >>On 23/04/15 19:18, Ben Pfaff wrote:
> >>>I don't think that the behavior you describe is intentional.  It sounds
> >>>like a bug or an unexpected interaction between features.  I think
> >>>you'll have to investigate and figure out why it's happening, and then
> >>>once we understand that it can be fixed.
> >>This is also how linux bridge works though, so maybe it is intentional(?).
> >>Although the linux bridge allows a forwarding delay of zero for cases where
> >>there's only one bridge.
> >We could make OVS support a forwarding delay of zero.  Presumably, that
> >risks loops, but we could argue that it's the sysadmin's choice.
> 
> Not sure I'd be comfortable with that. I used to get the same delays with
> linux bridges but now ping doesn't miss a single beat when an interface is
> added, and I don't understand why. The application quits every time on ovs
> and never with linux bridge. Maybe misconfiguration on my part?

Does it help to, when you add a VM, set stp-enable=false on the
interface?  You would, I think, need to add it in the same database
transaction (e.g. same ovs-vsctl invocation) that adds the port.

This is based on Jarno's suggestion here:
        http://openvswitch.org/pipermail/dev/2015-May/055266.html