Comment 3 for bug 2059721

Hi,

So, I totally see issues in ordering of tasks for OVN upgrade and couple of missing handlers we obviously need to cover.
However, I was able to launch OVN cluster after upgrade.

Basically, these steps should be taken for successful upgrade:

1. Upgrade/restart all ovn-controllers
2. Upgrade ovn-northd. Once it's upgraded you need to restart ovn-northd service and ovn-central right after it. Once 2 out of 3 ovn-northd are upgraded, DB upgrade will be performed to the new schema.

So eventually, I've updated 1st ovn-northd container to 22.04 and I got same output as you did:
root@aio1-neutron-ovn-northd-container-519166b6:/# ovn-nbctl --version
ovn-nbctl 23.03.1
Open vSwitch Library 3.1.2
DB Schema 7.0.0
root@aio1-neutron-ovn-northd-container-519166b6:/# ovsdb-client get-schema-version unix:/var/run/ovn/ovnnb_db.sock
6.1.0
root@aio1-neutron-ovn-northd-container-519166b6:/#

Then, I've updated second container to 22.04 and restarted ovn-northd and ovn-central, and got new schema on the first one right away:
root@aio1-neutron-ovn-northd-container-519166b6:/# ovsdb-client get-schema-version unix:/var/run/ovn/ovnnb_db.sock
7.0.0
root@aio1-neutron-ovn-northd-container-519166b6:/#

I will work on role/playbooks to cover upgrade process ordering and found nits.