Comment 2 for bug 1499000

I remember something like this in older ovs versions where the ifup was called by the init script; however that appears to have been dropped at some point in time both in Ubuntu and upstream in OVS as well.

I think that a manual ifup is required after installation of ovs - this will hook into the ovs supplied ifupdown scripts that manage the interfaces (and also start OVS if its not started - that might be the reason why it was dropped from the init/systemd/upstart scripts).