[Neutron] OVS agent is marking ports as dead before they are deleted

[Alexander Rubtsov]

--- Release ---
MOS 9.2

--- Description ---
(from the original upstream bug - https://bugs.launchpad.net/neutron/+bug/1493414)

When trying to clear the gateway port and tenant network interface delete in router, the OVS agent is marking the port as dead instead of treat them as removed: security group removed and port_unbound

This is causing to left stale OVS flows in br-int, and it may affect the port_unbound() logic in ovs_neutron_agent.py.

The ovs_neutron_agent is in one iteration of rpc_loop processing the deleted port via process_deleted_ports() method, marking the qg- port as dead (ovs flow rule to drop the traffic) and in another iteration, the ovs_neutron_agent is processing the removed port by treat_devices_removed() method.

In first iteration, the port deleting is triggered by port_delete() method:
2015-09-04 14:16:20.337 DEBUG neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent [req-e43234b1-633b-404d-92d0-0f844dadb586 admin 0f6c0469ea6e4d95a27782c46021243a] port_delete message processed for port 1c749258-74fb-498b-9a08-1fec6725a1cf from (pid=136030) port_delete /opt/openstack/neutron/neutron/plugins/ml2/drivers/openvswitch/agent/ovs_neutron_agent.py:410

and in second iteration, the device removed is triggered by ovsdb:
2015-09-04 14:16:20.848 DEBUG neutron.agent.linux.ovsdb_monitor [-] Output received from ovsdb monitor: {"data":[["bab86f35-d004-4df6-95c2-0f7432338edb","delete","qg-1c749258-74",49,["map",[["attached-mac","fa:16:3e:99:37:68"],["iface-id","1c749258-74fb-498b-9a08-1fec6725a1cf"],["iface-status","active"]]]]],"headings":["row","action","name","ofport","external_ids"]}
 from (pid=136030) _read_stdout /opt/openstack/neutron/neutron/agent/linux/ovsdb_monitor.py:50

Log from ovs neutron agent:
http://paste.openstack.org/show/445479/

Steps to reproduce:
1. Create router
2. Add tenant network interface to the router
3. Launch a VM
4. Add external network gateway to created router
5. Check the br-int for current port numbers
6. Remove external network gateway
7. Check the br-int for dead port flows (removed port qg-)
8. Remove the network interface from tenant network
9. Check the br-int for dead port flows.

Repeat the steps 4-9 few times to see if dead port flows will appear in br-int.

This is affecting the legacy, dvr and HA router.

[Alexander Rubtsov (arubtsov)]

sla2 for 9.0-updates

[Fuel Devops McRobotson (fuel-devops-robot)]

Fix proposed to branch: 9.0/mitaka
Change author: Denis V. Meltsaykin <email address hidden>
Review: https://review.fuel-infra.org/37132

[Fuel Devops McRobotson (fuel-devops-robot)]

Reviewed: https://review.fuel-infra.org/37132
Submitter: Pkgs Jenkins <email address hidden>
Branch: 9.0/mitaka

Commit: b4c645a69013a76ca18a37a3100955d7c207cdc4
Author: Denis V. Meltsaykin <email address hidden>
Date: Thu Nov 9 12:10:20 2017

Remove stale ofport drop-rule upon port-delete

When a port is deleted, that port is set to a dead-vlan, and
an ofport drop-flow is added in port_dead().

The ofport drop-flow gets removed only in some cases
in _bind_devices() - depending on the timing of the
concurrent port-deletion. In other cases, the drop-flow
never gets removed, and such garbage drop-flow rules
accumulate forever until the ovs-agent restarts.

The fix is to use the function update_stale_ofport_rules which
solves this problem of tracking stale ofport flows
in deleted ports, but currently only applies only to
prevent_arp_spoofing.

(cherry-picked from 5289d9494984b7c95407ad2f9b761b2e647953b2)

Change-Id: I0d1dbe3918cc7d7b3d0cdc49d7b6ff85f9b02a17
Closes-Bug: #1731208

[Vladimir Jigulin (vjigulin)]

Verified on 9.2-mu-4 using steps in description

[Fuel Devops McRobotson (fuel-devops-robot)]

Fix proposed to branch: mcp/1.0/mitaka
Change author: Denis V. Meltsaykin <email address hidden>
Review: https://review.fuel-infra.org/38064