openstack/neutron — Week of 2026-11-14

OVN backend. The bulk of the week's ~1,600 lines of churn landed in the OVN mechanism driver. Gateway routing on tunnelled GW networks now uses centralize_routing on the LRP, and the highest-priority chassis is demoted after a failover to avoid ping-pong. Stale MAC_Binding entries for port forwarding and router gateways are now cleaned up, tag_request is backfilled on existing localnet ports, and a duplicated Logical_Switch creation path was closed. Supporting changes add a hostname index to the SB Chassis table, teach ovsdb-client to use Southbound relays, read manager options lazily, and retry a port-binding update that hit DBDeadlock during migration (1015503).

L3 and ML2. The L3 service now publishes ROUTER_GATEWAY events for extra gateway ports, landing on master and one backport branch. ML2 port binding now stops immediately when a mechanism driver reports failure rather than continuing through the chain, also backported once. A new L3 option exposes the conntrack TCP established timeout, and segment notifications to Nova are now deferred until the DB transaction commits.

Agents and DHCP. The OVS agent now deletes the DVR ARP dst-mac flow from the correct table and retries ports skipped for an invalid ofport. The DHCP agent is told about DHCP-disabled subnets (landed across three branches), builds its resync throttler once, and no longer restarts a finished looping call.

Test stability. A race in test_cleanup_leftover_patch_ports_on_startup was fixed on master and backported to three stable branches, alongside several fixes for state leaks and batching races in the unit tests. Elsewhere: a Launchpad template refresh, a typo fix, and a Zuul skip rule for .agents changes.