[Segments] Network isn't scheduled to the dhcp agent in new segment when segment is added after subnet creation

[Slawek Kaplonski]

How to reproduce the issue:

1. Create network and e.g. 2 segments in it (but don't turn on neutron-ovs-agents in one of the specific segments, so hosts which belongs to that segment aren't really known to the neutron server)
2. Network will not be scheduled in that "unknown" segment,
3. Turn on ovs agent, it will report that it's there and what bridge mappings it has,
4. Neutron should schedule network to additional dhcp agent(s) which are on the hosts connected to the new segment, but it will not happen.

If things are don't in opposite order (first segment is recorded in neutron, next subnet is created) then network is scheduled to dhcp agents properly.

[Rodolfo Alonso (rodolfo-alonso-hernandez)]

Patch: https://review.opendev.org/c/openstack/neutron/+/778784

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 18.0.0.0rc1 release candidate.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/neutron/+/780835
Committed: https://opendev.org/openstack/neutron/commit/2fe402f4839baeddfc542300e84a41c2a069ab4e
Submitter: "Zuul (22348)"
Branch: stable/train

commit 2fe402f4839baeddfc542300e84a41c2a069ab4e
Author: Slawek Kaplonski <email address hidden>
Date: Thu Mar 4 23:18:16 2021 +0100

    Schedule networks to new segments if needed

    In case when subnet in segment X was created before hosts from
    that segment was mapped in the Neutron DB, network wasn't scheduled
    to the DHCP agents in that new segment.
    Now DHCP scheduler is triggered in such case.

    Closes-bug: #1917811
    Change-Id: Ic9e64aa4ecdc3d56f00c26204ad931b810db7599
    (cherry picked from commit 5c931f29132c3c5c01127f089f7d5909d2a19e4d)

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 15.3.4 release.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 16.3.2 release.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 17.1.2 release.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron queens-eol release.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron rocky-eol release.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron stein-eol release.