Symptom

• Error: Unable to attach interface. Details
  Unexpected API Error. Please report this at http://bugs.launchpad.net/nova/ and attach the Nova API log if possible. <class 'nova.exception_Remote.PortBindingFailed_Remote'> (HTTP 500) (Request-ID: req-cd901d79-6964-41f4-bd22-836f5397ac25)

Reference

• Do no set ovn-match-northd-version to true by default.
• This was introduced in commit ec21edf4d9d548c766dbe4ba9adfb045d0176bf4 when ovn-controllers were not updated before northdb.
•  Now, ovn-controller are updated first so the "Fail-safe upgrade" procedure[1] should not be used by default anymore.
• Closes-Bug: #2007870
• https://docs.ovn.org/en/latest/intro/install/ovn-upgrades.html#fail-safe-upgrade

Check pada master status network agent

$ openstack network agent list

Contoh hasil command diatas

Lihat ID Agent dengan status Alive XXX

Setelah itu masuk ke network agent dengan status XXX tersebut, pada tulisan ini misal
$ juju ssh 1 
#1 adalah ID Mesin network agent

setelah masuk, untuk ignore check version ketikan command berikut

$ sudo ovs-vsctl set open . external_ids:ovn-match-northd-version="false"

Kemudian restart service

$ sudo systemctl restart neutron-ovn-metadata-agent.service
$ sudo systemctl restart ovn-controller.service

Untuk melihat service yang running di linux

$ systemctl list-units --type=service | grep ovn