Comment 0 for bug 1823295

When the openvswitch-switch package is upgraded, the various daemons get restarted multiple times (see maintainer script below):

# Automatically added by dh_systemd_start/12ubuntu1
if [ "$1" = "configure" ] || [ "$1" = "abort-upgrade" ] || [ "$1" = "abort-deconfigure" ] || [ "$1" = "abort-remove" ] ; then
    if [ -d /run/systemd/system ]; then
        systemctl --system daemon-reload >/dev/null || true
        if [ -n "$2" ]; then
            _dh_action=restart
        else
            _dh_action=start
        fi
        deb-systemd-invoke $_dh_action 'ovs-vswitchd.service' 'ovsdb-server.service' >/dev/null || true
    fi
fi
# End automatically added section
# Automatically added by dh_systemd_start/12ubuntu1
if [ "$1" = "configure" ] || [ "$1" = "abort-upgrade" ] || [ "$1" = "abort-deconfigure" ] || [ "$1" = "abort-remove" ] ; then
    if [ -d /run/systemd/system ]; then
        systemctl --system daemon-reload >/dev/null || true
        if [ -n "$2" ]; then
            deb-systemd-invoke try-restart 'ovs-vswitchd.service' 'ovsdb-server.service' >/dev/null || true
        fi
    fi
fi
# End automatically added section
# Automatically added by dh_systemd_start/12ubuntu1
if [ "$1" = "configure" ] || [ "$1" = "abort-upgrade" ] || [ "$1" = "abort-deconfigure" ] || [ "$1" = "abort-remove" ] ; then
    if [ -d /run/systemd/system ]; then
        systemctl --system daemon-reload >/dev/null || true
        if [ -n "$2" ]; then
            deb-systemd-invoke try-restart 'ovs-vswitchd.service' 'ovsdb-server.service' >/dev/null || true
        fi
    fi
fi
# End automatically added section
# Automatically added by dh_installinit/12ubuntu1
if [ "$1" = "configure" ] || [ "$1" = "abort-upgrade" ] || [ "$1" = "abort-deconfigure" ] || [ "$1" = "abort-remove" ] ; then
    if [ -x "/etc/init.d/openvswitch-switch" ]; then
        update-rc.d openvswitch-switch defaults >/dev/null
        if [ -n "$2" ]; then
            _dh_action=restart
        else
            _dh_action=start
        fi
        invoke-rc.d openvswitch-switch $_dh_action || exit 1
    fi
fi
# End automatically added section

This results in a extended period of network loss for OVS ports - really the only one that is required is the restart of openvswitch-switch (which covers the other two as depends anyway).

ProblemType: Bug
DistroRelease: Ubuntu 19.04
Package: openvswitch-switch 2.11.0-0ubuntu1
ProcVersionSignature: Ubuntu 5.0.0-8.9-generic 5.0.1
Uname: Linux 5.0.0-8-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.10-0ubuntu25
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Fri Apr 5 08:24:32 2019
InstallationDate: Installed on 2018-10-18 (168 days ago)
InstallationMedia: Ubuntu 18.10 "Cosmic Cuttlefish" - Release amd64 (20181017.3)
SourcePackage: openvswitch
UpgradeStatus: Upgraded to disco on 2019-03-17 (18 days ago)