DVR SNAT Rocky Restarting openvswitch-switch service removes qr device from router namespace

[Liam Young]

In a bionic rocky DVR SNAT deploy restarting the openvswitch-switch
service causes the qr device to be permanently removed from the
router network namespace and hence connectivity to (and through)
the router is lost.

$ lsb_release -c
Codename: bionic

$ dpkg -l | grep neutron-common
ii neutron-common 2:13.0.7-0ubuntu1~cloud6 all Neutron is a virtual network service for Openstack - common

$ sudo ovs-vsctl show | grep -C4 37f7
    Bridge br-int
        Controller "tcp:127.0.0.1:6633"
            is_connected: true
        fail_mode: secure
        Port "qr-37f7f455-65"
            tag: 2
            Interface "qr-37f7f455-65"
                type: internal
        Port int-br-ex
            Interface int-br-ex
                type: patch

$ sudo ip netns exec qrouter-6a47605e-7262-4bf0-86a3-0e58eee4c9e0 ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: rfp-6a47605e-7@if2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether fe:2d:70:95:7e:c2 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 169.254.110.46/31 scope global rfp-6a47605e-7
       valid_lft forever preferred_lft forever
    inet6 fe80::fc2d:70ff:fe95:7ec2/64 scope link
       valid_lft forever preferred_lft forever
14: qr-37f7f455-65: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1450 qdisc noqueue state UNKNOWN group default qlen 1000
    link/ether fa:16:3e:cb:76:17 brd ff:ff:ff:ff:ff:ff
    inet 192.168.0.1/24 brd 192.168.0.255 scope global qr-37f7f455-65
       valid_lft forever preferred_lft forever
    inet6 fe80::f816:3eff:fecb:7617/64 scope link
       valid_lft forever preferred_lft forever

$ sudo systemctl restart openvswitch-switch

$ sudo ip netns exec qrouter-6a47605e-7262-4bf0-86a3-0e58eee4c9e0 ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: rfp-6a47605e-7@if2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether fe:2d:70:95:7e:c2 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 169.254.110.46/31 scope global rfp-6a47605e-7
       valid_lft forever preferred_lft forever
    inet6 fe80::fc2d:70ff:fe95:7ec2/64 scope link
       valid_lft forever preferred_lft forever

$ sudo ovs-vsctl show | grep -C4 37f7
    Bridge br-int
        Controller "tcp:127.0.0.1:6633"
            is_connected: true
        fail_mode: secure
        Port "qr-37f7f455-65"
            tag: 2
            Interface "qr-37f7f455-65"
                type: internal
        Port int-br-ex
            Interface int-br-ex
                type: patch

$ sudo systemctl restart neutron-openvswitch-agent
$ sudo systemctl restart neutron-l3-agent.service

$ sudo ip netns exec qrouter-6a47605e-7262-4bf0-86a3-0e58eee4c9e0 ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: rfp-6a47605e-7@if2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether fe:2d:70:95:7e:c2 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 169.254.110.46/31 scope global rfp-6a47605e-7
       valid_lft forever preferred_lft forever
    inet6 fe80::fc2d:70ff:fe95:7ec2/64 scope link
       valid_lft forever preferred_lft forever
$ sudo ovs-vsctl show | grep -C4 37f7
    Bridge br-int
        Controller "tcp:127.0.0.1:6633"
            is_connected: true
        fail_mode: secure
        Port "qr-37f7f455-65"
            tag: 2
            Interface "qr-37f7f455-65"
                type: internal
        Port int-br-ex
            Interface int-br-ex
                type: patch

[Liam Young (gnuoy)]

An upgrade to stein fixed this for me.