OVS DPDK restart results in that tap interfaces in network namespaces can't be opened

[Yi Yang]

If OVS DPDK is restarted, tap interfaces in network namespaces can't be opened because OVS DPDK doesn't know these name spaces, so OVS DPDK restart will result in that tap interfaces in qr-XXX, fg-XXX, qg-XXX and qdhcp-xxx network namespaces can't be opened by OVS DPDK, OVS DPDK will create new tap interfaces in root namespace, the result is l3 routing, floating IP, DHCP, metadata proxy and snat can't work.

[Hongbin Lu (hongbin.lu)]

Hi, please provide the following information:

* Can this problem reproducible? If yes, what are the reproducing steps?
* Which version of neutron you are using?
* How did you configure neutron? (better to attach the config file)
* How did you install neutron (kolla-ansible? devstack? or others?)
* The logs of all neutron processes.

[Hongbin Lu (hongbin.lu)]

I will set this bug to "incomplete" for now. Please feel free to re-open it once you have the information above ready.

[Yi Yang (yangyi01)]

* Can this problem reproducible? If yes, what are the reproducing steps?

It can be reproduced very easily as long as you use OVS DPDK and DVR mode. you can reproduce it after qrouter, dhcp, snat or fip namespaces are added and OVS DPDK is restarted.

* Which version of neutron you are using?

Victoria, this is an OVS-DPDK-specific issue.

* How did you configure neutron? (better to attach the config file)

in DVR use case.

* How did you install neutron (kolla-ansible? devstack? or others?)

devstack, openstack-helm

* The logs of all neutron processes.

bug statement has explained it very clearly. When OVS DPDK is restared, OVS DPDK doesn't know network namespaces of qr-XXXX, fg-XXXX, tap-XXXX, qg-XXXX, sg-XXXX, so OVS DPDK will recreate them in root namespace, OVS DPDK will use these newly-created ports, but neutron is using the old ones in namespaces, this is the issue/bug I'm saying.

[Yi Yang (yangyi01)]

https://review.opendev.org/c/openstack/neutron/+/818338 is just to fix it. By the way, OVS DPDK must be modified to take this netns option in order that it can open tap interfaces in corresponding network namespaces.

[Slawek Kaplonski (slaweq)]

This bug has had a related patch abandoned and has been automatically un-assigned due to inactivity. Please re-assign yourself if you are continuing work or adjust the state as appropriate if it is no longer valid.

[OpenStack Infra (hudson-openstack)]

Change abandoned by "Slawek Kaplonski <email address hidden>" on branch: master
Review: https://review.opendev.org/c/openstack/neutron/+/818338
Reason: This review is > 4 weeks without comment, and failed Zuul jobs the last time it was checked. We are abandoning this for now. Feel free to reactivate the review by pressing the restore button and leaving a 'recheck' comment to get fresh test results.