optimize reload/restart of openvswitch-switch

[James Page]

A reload of openvswitch-switch is particularly disruptive to existing network flows resulting an a 10 second or so pause while the datapath rebuilds.

Its possible todo a more optimized flow save/restore and orchestrated restart of the ovs daemons to minimise and disruption to a second or two at most.

[James Page (james-page)]

I can optimise the 'reload' capabilities of the systemd units, however its not possible to use those as part of the debhelper generated systemd management code; using reload rather than restart appears to be an inflight feature in Debian:

https://salsa.debian.org/debian/debhelper/merge_requests/14

https://salsa.debian.org/debian/init-system-helpers/merge_requests/5

[Launchpad Janitor (janitor)]

This bug was fixed in the package openvswitch - 2.12.0~git20190903.1cdf291dc-0ubuntu1

---------------
openvswitch (2.12.0~git20190903.1cdf291dc-0ubuntu1) eoan; urgency=medium

  * New upstream snapshot from 2.12 branch.
  * d/p/0001-acinclude-Also-use-LIBS-from-dpkg-pkg-config.patch: Drop,
    included upstream.
  * d/control: Bumped Standards-Version to 4.4.0.
  * d/control,rules: Drop Python 2 support.
  * d/rules: Disable testing of DPDK build on arm64 as builders don't
    have the required crc32 CPU feature.
  * d/control: Version BD for libdpdk-dev to ensure buid without overlinking.

 -- James Page <email address hidden> Fri, 06 Sep 2019 09:46:28 +0100