To change the system ID to UUID format is not a solution but the only way OVS system-id can be configured. If this ID was incorrectly set initially, that was a configuration issue. OVS does not fail when this ID has not UUID format but it should. And now the OVS metadata agent will exit with an exception.
As reported in this BZ, you need to stop the affected ovn-controllers, delete the Chassis and Chassis_Private registers, delete the OVN agents in Neutron (if present) and restart the ovn-controller again.
Hello Bartosz:
To change the system ID to UUID format is not a solution but the only way OVS system-id can be configured. If this ID was incorrectly set initially, that was a configuration issue. OVS does not fail when this ID has not UUID format but it should. And now the OVS metadata agent will exit with an exception.
As reported in this BZ, you need to stop the affected ovn-controllers, delete the Chassis and Chassis_Private registers, delete the OVN agents in Neutron (if present) and restart the ovn-controller again.
I'll mark this bug as a duplicate of LP#1952550.
Regards.