Comment 1 for bug 1998952

I can confirm that adding/removing a route that is the same as the subnet of the attached router interface can cause issues. I saw something different than described in that I didn't see a duplicate route, but in the end I was left without my interface route.

For example...

# Added second subnet and interface on router, 10.0.0.64/26 here:

default via 172.24.4.1 dev qg-ae7b835f-4a proto static
10.0.0.0/26 dev qr-648ebb56-c3 proto kernel scope link src 10.0.0.1
10.0.0.64/26 dev qr-c052ba70-be proto kernel scope link src 10.0.0.65
172.24.4.0/24 dev qg-ae7b835f-4a proto kernel scope link src 172.24.4.209

# Added route, which removed existing interface route
$ openstack router set router1 --route destination=10.0.0.64/26,gateway=10.0.0.10

default via 172.24.4.1 dev qg-ae7b835f-4a proto static
10.0.0.0/26 dev qr-648ebb56-c3 proto kernel scope link src 10.0.0.1
10.0.0.64/26 via 10.0.0.10 dev qr-648ebb56-c3 proto static
172.24.4.0/24 dev qg-ae7b835f-4a proto kernel scope link src 172.24.4.209

# Removed route, so router still has interface, but no route to the local subnet
$ openstack router remove route router1 --route destination=10.0.0.64/26,gateway=10.0.0.10

default via 172.24.4.1 dev qg-ae7b835f-4a proto static
10.0.0.0/26 dev qr-648ebb56-c3 proto kernel scope link src 10.0.0.1
172.24.4.0/24 dev qg-ae7b835f-4a proto kernel scope link src 172.24.4.209