In the condition that there are more than one external network:
Testing procedure:
1 Creating several external networks
2 Creating a router
3 running command "neutron router-gateway-set router-ID external-network-ID"
neutron server reported error after executed command above:
Bad router request: No eligible l3 agent associated with external network 784fbbdd-4c91-4944-9dce-8a1f767b4097 found.
Problem analysis:
When running command router-gateway-set, it will update_router and then check if router need schedule. The method _check_router_needs_rescheduling in l3_db.py file as below[1] will neglect schedule with non-agent-based implementation of l3 services, such as Dragonflow.
Sustainable Solution:
There is no need to import object of router_scheduler_driver[2], because DF don't need it now.
[1] https://github.com/openstack/neutron/blob/master/neutron/db/l3_db.py#L277
[2] https://github.com/openstack/dragonflow/blob/master/dragonflow/neutron/services/l3_router_plugin.py#L73
@jingting, what are the effects of the exception? Does the system continue to operate as expected, is admin intervention required, or is the command simply ignored?
This is important to understand the severity of this bug.