Current Series Release Notes¶

29.0.0.0rc1-94¶

Added support for the OpenTelemetry tracing middleware provided by oslo.middleware. The middleware is wired into the Neutron API paste pipeline and is disabled by default, acting as a zero-overhead passthrough when off. To enable distributed tracing, set enabled = True under the [oslo_middleware_tracing] group in neutron.conf and install the optional OpenTelemetry packages.

Setting the trusted key directly in a port’s binding:profile, which was deprecated in 2024.2, is no longer allowed. The dedicated port attribute trusted, added by the API extension port_trusted_vif should be used instead.

Neutron now refuses to start when [ml2_type_vlan] network_vlan_ranges no longer covers a VLAN ID that a network segment still holds, either because a range was narrowed or because a physical network was dropped from it. The error names the physical networks and VLAN IDs involved. Restore the ranges in the configuration file, or delete the networks holding those VLAN IDs, to start again. Network segment ranges created through the API are not affected: their allocated registers are kept and Neutron starts normally, since an administrator could not otherwise reach the API to undo such a change.

Tunnel type segments (VxLAN, GRE, Geneve) now store physical_network = '' (empty string) instead of NULL in the networksegments table. An expand migration converts existing NULL values automatically and adds a UNIQUE constraint on (network_type, physical_network, segmentation_id), which prevents duplicate segment allocations at the database level for VLAN and tunnel types.

If the database contains corrupt duplicate tunnel segments (the same network_id, network_type, and segment_index with physical_network = NULL), the migration will fail and the operator must resolve the duplicates manually. The networksegments_unique_constraint_check entry in neutron-status upgrade check detects this condition before the migration runs.

The standalone OVN Metadata agent (neutron-ovn-metadata-agent) has been removed. It was deprecated in 2025.2 in favor of the OVN agent with the “metadata” plugable extension enabled. To migrate, stop the OVN Metadata agent and start the OVN agent (neutron-ovn-agent) with the metadata extension enabled in the configuration file (extensions = metadata in the [DEFAULT] section). The rest of the configuration is the same; the new agent can reuse the old configuration files.

The configuration options [ovn]ovs_create_tap and [OVS_DRIVER]ovs_create_tap are removed. Neutron always sets ovs_create_tap: True in the port vif_details for kernel OVS ports, enabling os-vif TAP pre-creation during live migration. Remove these options from neutron.conf if present.

The default delete_port policy now denies deletion of ports with device_owner network:distributed, such as the OVN metadata port, unless the caller is an admin, a service user, or a project member or network owner whose request also carries a service token. A new helper rule distributed_device was added. Deployments with customized policy files should review and update delete_port if they rely on the previous behaviour.

The OVS trunk service driver now removes stale tpi- and spi- patch ports from the integration bridge at agent startup when their peer on the trunk bridge no longer exists (i.e. the trunk bridge was already deleted). This can happen after a compute host crash and VM evacuation, where the source host never ran its trunk teardown.

Fixed the ML2/OVS agent on the source host sending a spurious network-vif-plugged event during live migration. When the source agent received a port_update for the new INACTIVE binding on the destination host, it can happen that the agent re-processes the migrating port and calls update_device_up(), making Nova beleive the port is ready for traffic on the destination. The source agent now detects that a port is being migrated to another host (either from the binding profile or, as a fallback, from an INACTIVE binding on a different host) and skips processing it. See bug: 2162710.

ML2 mechanism drivers can now raise the existing neutron_lib.exceptions.PortBindingError from bind_port() when binding cannot safely continue. ML2 stops trying other mechanism drivers, including at higher levels of hierarchical binding, clears partial binding state, and records binding_failed. Other exceptions continue to be logged and ignored so later drivers may bind the port. [bug 2149843]

Fixed an issue in the OVN trunk driver where trunks were incorrectly managed for parent ports with type=external (e.g., baremetal/SR-IOV ports). The driver now checks the Logical Switch Port type and skips trunk management for external ports, leaving it to the appropriate out-of-band mechanism driver. For more information see bug 2167105.

The L3 agent now starts keepalived with -B (no BFD subsystem) if keepalived was built with BFD support. Since keepalived 2.3.2 every instance locks the BFD PID file, /run/bfd.pid by default, so HA routers failed to start if /run was read-only or if several routers were started at the same time.

Synchronizing the VLAN allocations no longer deletes allocated registers when it removes the registers of a physical network that is no longer configured. Deleting them discarded the only record that a segmentation ID was in use while the network segment referencing it still existed. Allocated registers are now kept and removed when their segment is released, which matches both the per-VLAN removal in the same routine and the behaviour of the tunnel type drivers. See bug: 2167266.

Tunnel segments with physical_network = NULL did not participate correctly in UNIQUE constraints on networksegments because SQL treats NULL values as distinct. See LP#2168770.

The OVN mechanism driver no longer uses the first port binding of a port to decide whether the port is an external port (lsp.type=external). When a port has multiple bindings, for example during live migration, the first binding could be the inactive one, resulting in the wrong VNIC type and capabilities being evaluated. The ACTIVE binding is now used.

Fixed a race condition in the ML2/OVN mechanism driver where a nova instance rebuild could time out waiting for the network-vif-plugged event. During a rebuild nova unplugs and quickly replugs the VIF on the same chassis, so the Logical_Switch_Port may never transition from DOWN to UP and LogicalSwitchPortUpdateUpEvent is not fired. The PortBindingChassisUpdateEvent now also matches a port being (re)bound to a chassis while the LSP stays up, emitting the required port status update (and therefore the vif-plugged event).

Fixed a KeyError when retrieving a port with a QoS policy that had no associated port binding register. The API now returns the port without a resource request and logs an error instead. For more information, see bug 2166602.

Project members can no longer delete the OVN metadata port of their network with DELETE /v2.0/ports/{id}. Deleting it broke metadata access for the instances of the network. Admin users can still delete it. For more information, see bug 1764408.

Adding a router interface on a subnet that is already attached to the router now fails with Router already has a port on subnet on routers supporting multiple external gateways (for example the OVN L3 plugin), instead of reporting that the subnet overlaps with itself. For more information, see bug 2170284.

Added extension network-segment-range to the ML2/OVN mechanism driver supported API extension list.