Limitation to schedule guest for a given segment

[Sahid Orentino]

There is a limitation today in Nova when using routed provider network. Even if the scheduler is able to select the right host. It will not be able to select the right segment for a given fixed IP.

The current algorithm sticks on selecting the first segment that it discovers.

[Sylvain Bauza (sylvain-bauza)]

Which release are you talking ? I guess you're using Wallaby or later, as we added scheduling capabilities for routed networks in there :
https://specs.openstack.org/openstack/nova-specs/specs/wallaby/implemented/routed-networks-scheduling.html

IIUC, you're refering to a limitation we have in the current prefilter, which takes the first subnet of a list based on the fixed IP that was passed.
https://github.com/openstack/nova/blob/c53ec4e48884235566962bc934cbf292ad5b67b8/nova/scheduler/request_filter.py#L327-L330

Putting this bug report as Incomplete until we figure out the exact need.

[Sahid Orentino (sahid-ferdjaoui)]

Not exactly.

Talking about master. Specifically this limitation [0]. Currently it takes the first segment that it finds. In a multi-segments deployment you may want to ensure that you pick the right segment.

[0] https://github.com/openstack/nova/blob/c53ec4e48884235566962bc934cbf292ad5b67b8/nova/network/neutron.py#L2150

[Sylvain Bauza (sylvain-bauza)]

OK, now I better understand your ask.
I'm not really sure this is a bug honesly we could easily fix, a blueprint seems better for me in order to track the progress so I'll pout the status to Invalid/Wishlist and anyone wanting to work on it will just have to create a blueprint.