When installing an OpenShift cluster with OVN-Kubernetes in a specific OpenStack cloud used for some CI jobs we've notice the ovnkube-node Pod
crashloops because "F1027 10:10:08.351527   31511 ovnkube.go:133] error looking up gw interface: "br-ex", error: Link not found". Installation is unable to progress. Two services have failed on the master nodes afterburn-hostname.service and ovs-configuration.service. 

Additional information that might be helpful, the network of the nodes have a MTU of 1242 configured.

DEVICE          TYPE           STATE      CONNECTION         
ens3            ethernet       connected  Wired connection 1 
genev_sys_6081  geneve         unmanaged  --                 
lo              loopback       unmanaged  --                 
br-int          ovs-bridge     unmanaged  --                 
br-int          ovs-interface  unmanaged  --                 
ovn-k8s-mp0     ovs-interface  unmanaged  --                 
br-int          ovs-port       unmanaged  --                 
ovn-e8fef9-0    ovs-port       unmanaged  --                 
ovn-k8s-mp0     ovs-port       unmanaged  -- 

[core@sqknth4w-71fac-gnwxk-master-1 ~]$ sudo systemctl status ovs-configuration.service
● ovs-configuration.service - Configures OVS with proper host networking configuration
   Loaded: loaded (/etc/systemd/system/ovs-configuration.service; enabled; vendor preset: enabled)
   Active: failed (Result: exit-code) since Thu 2022-10-27 09:52:51 UTC; 1h 22min ago
  Process: 1578 ExecStart=/usr/local/bin/configure-ovs.sh OVNKubernetes (code=exited, status=3)
 Main PID: 1578 (code=exited, status=3)
      CPU: 1.528s

Oct 27 09:52:51 sqknth4w-71fac-gnwxk-master-1 configure-ovs.sh[5434]: default via 10.0.0.1 dev ens3 proto dhcp src 10.0.0.27 metric 100
Oct 27 09:52:51 sqknth4w-71fac-gnwxk-master-1 configure-ovs.sh[5434]: 10.0.0.0/16 dev ens3 proto kernel scope link src 10.0.0.27 metric 100
Oct 27 09:52:51 sqknth4w-71fac-gnwxk-master-1 configure-ovs.sh[5434]: 169.254.169.254 via 10.0.0.10 dev ens3 proto dhcp src 10.0.0.27 metric 100
Oct 27 09:52:51 sqknth4w-71fac-gnwxk-master-1 configure-ovs.sh[1578]: + ip -6 route show
Oct 27 09:52:51 sqknth4w-71fac-gnwxk-master-1 configure-ovs.sh[5435]: ::1 dev lo proto kernel metric 256 pref medium
Oct 27 09:52:51 sqknth4w-71fac-gnwxk-master-1 configure-ovs.sh[1578]: + exit 3
Oct 27 09:52:51 sqknth4w-71fac-gnwxk-master-1 systemd[1]: ovs-configuration.service: Main process exited, code=exited, status=3/NOTIMPLEMENTED
Oct 27 09:52:51 sqknth4w-71fac-gnwxk-master-1 systemd[1]: ovs-configuration.service: Failed with result 'exit-code'.
Oct 27 09:52:51 sqknth4w-71fac-gnwxk-master-1 systemd[1]: Failed to start Configures OVS with proper host networking configuration.
Oct 27 09:52:51 sqknth4w-71fac-gnwxk-master-1 systemd[1]: ovs-configuration.service: Consumed 1.528s CPU time

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