openstack/neutron — Week of 2026-09-26

BGP and OVN backend. The headline change reworks BGP dynamic routing to run reconciliation when the OVSDB lock is acquired, a ~330-line rewrite in 1005805. Alongside it, OVN gained advertisement of the RBAC address group and subnet pool extensions, picked up ip_substring_filtering API extension support (with a stable backport), and had EVPN db-sync repair taught to preserve non-EVPN HA chassis groups. The BGP CI also pinned OVN_BRANCH to v26.03.3 and skipped a mismatched-BGP-password test on FIPS.

Trunk driver. External-type parent ports are now excluded from OVN trunk management; the fix landed on master and was backported to three stable branches, making it the most-propagated change of the week.

Stability and bug fixes. The ovs-agent no longer deletes stale flows at startup, closing a race that could disrupt datapath traffic. Metadata and OVN LB health-monitor ports no longer get MTU set to None when created by non-ML2 callers (backported once). A QoS resource-request path now tolerates missing port bindings, and an OVO fix clears the qos_network_policy_id dirty flag after DB load — that one was backported across four stable branches. A one-line DHCP fix restricting dnsmasq --dhcp-range to local subnets was similarly backported three times.

Elsewhere. Housekeeping replaced lingering references to [ml2] tenant_network_types and the legacy Nova security group API, and 2026.1 CI switched to the branched iptables_hybrid job.