[ovn] External Gateway Loop in NB SB DB

[Ammad Ali]

Hi,

I have installed neutron 20.0 and OVN 22.03 on ubuntu 22.04. When I create a router and attach external network with it, it generate loop thousands of ovn NB and SB DB transection cause the DB size grows.

In SB

OVSDB JSON 300 0f200aa6397e53cd203c99e6674bda75bdd53151
{"_date":1654929577073,"Multicast_Group":{"9b50bf0f-f9fe-4b9a-9333-fe2d1744575c":{"ports":["uuid","efc3d1a7-56a6-4235-8a29-4d1defdb459c"]}},"_is_diff":true,"_comment":"ovn-northd","Port_Binding":{"efc3d1a7-56a6-4235-8a29-4d1defdb459c":{"external_ids":["map",[["neutron:revision_number","10678"]]]}}}
OVSDB JSON 402 86de47a7521717bd9ab7182422a6ad9b424c93d0
{"_date":1654929577345,"Multicast_Group":{"9b50bf0f-f9fe-4b9a-9333-fe2d1744575c":{"ports":["uuid","efc3d1a7-56a6-4235-8a29-4d1defdb459c"]}},"_is_diff":true,"_comment":"ovn-northd","Port_Binding":{"d34d2dd5-260b-4253-8429-5a7a89f3a500":{"external_ids":["map",[["neutron:revision_number","10679"]]]},"2ce0135e-b9b5-441b-aaae-7ce580bcf600":{"external_ids":["map",[["neutron:revision_number","10679"]]]}}}

and In NB

OVSDB JSON 334 e0ee7ff61d595e6151abd694ce2179c11d9e2570
{"_date":1654929536919,"_is_diff":true,"Logical_Router_Port":{"a0c2e43e-f4cb-4331-b070-a726b3da7a17":{"external_ids":["map",[["neutron:revision_number","10567"]]]}},"Logical_Switch_Port":{"cc97ca2c-979e-4754-a8d2-4fff0a666df8":{"options":["map",[["mcast_flood_reports","true"],["requested-chassis","kvm01-a1-r17-lhr01.rapid.pk"]]]}}}
OVSDB JSON 269 dd8f87d8b132415a423b0f020b23f07d2488acba
{"_date":1654929536992,"Logical_Switch_Port":{"cc97ca2c-979e-4754-a8d2-4fff0a666df8":{"options":["map",[["mcast_flood_reports","true"],["requested-chassis","kvm01-a1-r17-lhr01.rapid.pk"]]],"external_ids":["map",[["neutron:revision_number","10567"]]]}},"_is_diff":true}
OVSDB JSON 334 42d2a02531bd91d88b8783a45da47a33b5e3dc94
{"_date":1654929537262,"_is_diff":true,"Logical_Router_Port":{"a0c2e43e-f4cb-4331-b070-a726b3da7a17":{"external_ids":["map",[["neutron:revision_number","10568"]]]}},"Logical_Switch_Port":{"cc97ca2c-979e-4754-a8d2-4fff0a666df8":{"options":["map",[["mcast_flood_reports","true"],["requested-chassis","kvm01-a1-r17-lhr01.rapid.pk"]]]}}}
OVSDB JSON 269 b8454f003de8cb14961aa37d5a557d2490d34049
{"_date":1654929537355,"Logical_Switch_Port":{"cc97ca2c-979e-4754-a8d2-4fff0a666df8":{"options":["map",[["mcast_flood_reports","true"],["requested-chassis","kvm01-a1-r17-lhr01.rapid.pk"]]],"external_ids":["map",[["neutron:revision_number","10568"]]]}},"_is_diff":true}
OVSDB JSON 334 705b3007e83f0646642510903602965a6192fccf
{"_date":1654929537648,"_is_diff":true,"Logical_Router_Port":{"a0c2e43e-f4cb-4331-b070-a726b3da7a17":{"external_ids":["map",[["neutron:revision_number","10569"]]]}},"Logical_Switch_Port":{"cc97ca2c-979e-4754-a8d2-4fff0a666df8":{"options":["map",[["mcast_flood_reports","true"],["requested-chassis","kvm01-a1-r17-lhr01.rapid.pk"]]]}}}
OVSDB JSON 269 4506e6ee9336bf2b8bde3134badbea7d23e72d33

I also see below logs in ovn-northd.log

2022-06-11T06:46:55.927Z|00171|northd|WARN|Dropped 650 log messages in last 60 seconds (most recently, 0 seconds ago) due to excessive rate
2022-06-11T06:46:55.927Z|00172|northd|WARN|Unknown chassis '' set as options:requested-chassis on LSP '426cf7d5-4fd7-4aa9-806b-9dbe170c543e'.
2022-06-11T06:47:55.941Z|00173|northd|WARN|Dropped 644 log messages in last 60 seconds (most recently, 0 seconds ago) due to excessive rate
2022-06-11T06:47:55.941Z|00174|northd|WARN|Unknown chassis '' set as options:requested-chassis on LSP '426cf7d5-4fd7-4aa9-806b-9dbe170c543e'.

I have tested it on ubuntu 20.04 via UCA AND 22.04. Below are the test scenerio.

- Two gateway chassis
- 5 compute nodes

I have also tested this with one chassis as well, for which I am attaching neutron-server.log when I attached external interface to router and ovn nb and sb DBs as well.

I would be happy to provide any further info that is needed.

Ammad

[yatin (yatinkarel)]

This looks duplicate of https://bugs.launchpad.net/neutron/+bug/1973347 and is fixed with https://review.opendev.org/c/openstack/neutron/+/842147. This should be backported to stable branches as well.

@Ammad Can you try out the patch and confirm it fixes the issue for your?

For now i will mark out it as duplicate of other lp i.e 1973347, please reopen if you still consider it different issue once you check other bug and the fix.