Comment 0 for bug 1592534

Reproducible on - all version up to 8.0, have not tried on 9.0

Description:
  restarting neutron-plugin-openvswitch-agent introduces network downtime
  stop of the agent does not introduce downtime, but start does.

Steps to reproduce:
  1 - start ping of a floating ip / internal ip of a VM
  2 - stop neutron-plugin-openvswitch-agent on compute
  3 - start neutron-plugin-openvswitch-agent on compute
  4 - observe several lost packets

I believe it should be possible to start agent without manipulating ovs internals if they are already correctly set up - we need to make necessary checks (read operations) and act based on results, and avoid touching anything which is already configured correctly.

I believe the same issue is with neutron-l3-agent.