Zed Series Release Notes


Upgrade Notes

  • The default value for the metadata_workers configuration option has changed to 0 for the ML2/OVN driver. Since [OVN] Allow to execute “MetadataProxyHandler” in a local thread, the OVN metadata proxy handler can be spawned in the same process of the OVN metadata agent, in a local thread. That reduces the number of OVN SB database connections to one.

Other Notes

  • Since OVN 20.06, the “Chassis” register configuration is stored in the “other_config” field and replicated into “external_ids”. This replication is stopped in OVN 22.09. The ML2/OVN plugin tries to retrieve the “Chassis” configuration from the “other_config” field first; if this field does not exist (in OVN versions before 20.06), the plugin will use “external_ids” field instead. Neutron will be compatible with the different OVN versions (with and without “other_config” field).



Introduce the experimental features framework.

New Features

  • Some Neutron features are not supported due to lack of resources or technical expertise to maintain them. As they arise, those features will be marked as experimental by the Neutron core team. Deployers will be able to continue using experimental features by explicitly enabling them in the ‘experimental’ section of neutron.conf. The ML2 linuxbridge driver is the first feature to be marked as experimental. To continue using it, deployers have to set to True the ‘linuxbridge’ option in the ‘experimental’ section of neutron.conf.

  • Add support for port ranges in the port forwarding rules. The supported ranges are N:M with N <= M. Also, the ranges of internal and external ports relation must be: internal range = external range or internal range = 1.

  • After the port is considered as provisioned, the Nova port binding update could have not been received, leaving the port as not bound. Now the port provisioning method has an active wait that will retry several times, waiting for the port binding update. If received, the port status will be set as active if the admin state flag is set.

  • Support for IPv6 NDP proxy has been added. Read the related specification for more details.

  • Support for baremetal provisioning using OVN’s built-in DHCP server has been added for IPv4.

  • Added support for QoS minimum bandwidth rules (egress only) in ML2/OVN. OVN supports setting these rule types in the logical switch ports since release 22.06.0.

  • OVN mechanism driver refuses to bind a port to a dead agent.

  • Core OVN now can set the destination host on the logical switch port during a live migration. That allows to prepare the destination host earlier, achieving a quicker live migration and a lower downtime during the switch between hosts. Neutron includes this information in the port options.

  • Added support for router gateway IP QoS in OVN backend. The L3 OVN router plugin now can apply router QoS policy rules on the router gateway port.

  • Ovn configuration items “ovn_nb_connection” and “ovn_sb_connection” can set multiple addresses separated by commas. Setting NB/SB “connection” inactivity probe can also work well, if multiple connection be specified.

  • Added a new configuration variable, in [OVS] section, to control the OVS OpenFlow rule processing operations when using the OVS native firewall driver (securitygroup.firewall_driver=openvswitch):

    • openflow_processed_per_port: by default “False”. If enabled, all OpenFlow rules associated to a port will be processed at once, in a single transaction. If disabled, the flows will be processed in batches of “AGENT_RES_PROCESSING_STEP=100” number of OpenFlow rules.

  • If uplink-status-propagation extension is enabled, all existing ports before enabling it will have the flag “propagate_uplink_status” enabled by default. This is aligned with the aim of an administrator that enables this extension. Now only new ports can be created with this flag disabled.

  • Gateway IP QoS network inheritance is now available for OVN L3 plugin QoS extension. If the router external network (gateway network) has a QoS policy associated, the gateway IP port will inherit the network QoS policy.

  • QoS rule type list accepts two filter flags:

    • all_supported: if True, the listing call will print all QoS rule types supported by at least one loaded mechanism driver.

    • all_rules: if True, the listing call will print all QoS rule types supported by the Neutron server.

    Both filter flags are exclusive and not required.

  • Enabled DbQuotaDriverNull as production ready database quota driver. This driver does not have access to the database and will return empty values to the request queries. This driver can be used to override the Neutron quota engine.

  • A new script to remove the duplicated port bindings was added. This script will list all ml2_port_bindings records in the database, finding those ones with the same port ID. Then the script removes those ones with status=INACTIVE. This script is useful to remove those leftovers that remain in the database after a failed live migration. It is important to remark that this script should not be executed during any live migration process.

  • Add use_random_fully setting to allow an operator to disable the iptables random-fully property on an iptable rules.

Known Issues

  • If the use_random_fully setting is disabled, it will prevent random fully from being used and if there’re 2 guests in different networks using the same source_ip and source_port and they try to reach the same dest_ip and dest_port, packets might be dropped in the kernel do to the racy tuple generation . Disabling this setting should only be done if source_port is really important such as in network firewall ACLs and that the source_ip are never repeating within the platform.

Upgrade Notes

  • Previously deprecated configuration option allow_overlapping_ips is now removed.

  • Python 3.6 & 3.7 support has been dropped. The minimum version of Python now supported is Python 3.8.

  • A new configuration option called [ovn]/disable_ovn_dhcp_for_baremetal_ports has been added to ML2/OVN for IPv4. Since PXE booting nodes can be very sensitive depending on the hardware and some operators may prefer to use a fully-fledged DHCP server instead of OVN’s DHCP server this option allows for disabling OVN’s built-in DHCP server for baremetal ports (vnic type “baremetal”) when set to True. It defaults to False.

Deprecation Notes

  • The ML2 linuxbridge agent has been marked as experimental due to lack of resources to maintain it. To continue using it, deployers have to set to True the ‘linuxbridge’ option in the ‘experimental’ section of neutron.conf

Bug Fixes

  • 1942329 Port binding logic for direct-physical ports has been extended to allow providing the MAC address of the physical device via the binding profile. If it is provided then Neutron overwrites the value of the device_mac_address field of the port object in the database with the value from the active binding profile. If there are ports bound before the nova side of this fix is depolyed then the VM using the port needs to be moved or the port needs to be detached and re-attached to force nova to provide the MAC address of the direct-physical port in the port binding.

  • Forbid the creation of a duplicate NDP proxy entry on the same router, since the IP address of a router is unique and an IPv6 address only needs one NDP proxy.

  • Fixes an issue in the ML2/OVN driver where the network segment tag was not being updated in the OVN Northbound database. For more information, see bug 1944708.

Other Notes

  • The OVN migration performs validation by default. This validation means an instance is spawned and is tested by simple ping after the migration is finished. Also it tries to create new workload post migration. This is useful for very simple scenarios when migration is tested but is not really useful in production since likely the production envrionments already have running workloads. It makes more sense to require the validation explicitly rather than implicitly run it as the migration is mostly intended for production. The VALIDATE_MIGRATION now defaults to False and needs to be changed to True if validation upon request.

  • From now on, gateway interface will be kept up on all nodes where HA router is hosted, regardless of their state (active or standby). For more information see bug 1952907.

  • OVN driver reverted to using stateful NAT for floating IP implementation. The previous switch to stateless didn’t materialize the expected performance benefits and instead introduced problems with potential hardware offloading.