When an interface is moved to a new namespace, specially with OVS
internal ports, the interface first dissapears from any network
namespace and then is added again. ovs-vswitchd service detects
this interface change as reported in [1]. This delay is the cause
of the related bug, where some interfaces are not present when
the L3 agent needs to manipulate them.
[1]https://bugs.launchpad.net/neutron/+bug/1948832/comments/3
Conflicts:
neutron/tests/functional/agent/linux/test_ip_lib.py
Closes-Bug: #1948832
Change-Id: I3af4d0afa784899689ccb595ce6ba64495431eb9
(cherry picked from commit ebc4766990)
(cherry picked from commit 9c41365041)