Networking in Kolla

Networking in Kolla

Kolla deploys Neutron by default as OpenStack networking component. This section describes configuring and running Neutron extensions like LBaaS, Networking-SFC, QoS, and so on.

Enabling Provider Networks

Provider networks allow to connect compute instances directly to physical networks avoiding tunnels. This is necessary for example for some performance critical applications. Only administrators of OpenStack can create such networks. For provider networks compute hosts must have external bridge created and configured by Ansible tasks like it is already done for tenant DVR mode networking. Normal tenant non-DVR networking does not need external bridge on compute hosts and therefore operators don’t need additional dedicated network interface.

To enable provider networks, modify the /etc/kolla/globals.yml file as the following example shows:

enable_neutron_provider_networks: "yes"

Enabling Neutron Extensions


Preparation and deployment

Modify the /etc/kolla/globals.yml file as the following example shows:

enable_neutron_sfc: "yes"


For setting up a testbed environment and creating a port chain, please refer to networking-sfc documentation.

Neutron VPNaaS (VPN-as-a-Service)

Preparation and deployment

Modify the /etc/kolla/globals.yml file as the following example shows:

enable_neutron_vpnaas: "yes"


VPNaaS is a complex subject, hence this document provides directions for a simple smoke test to verify the service is up and running.

On the network node(s), the neutron_vpnaas_agent should be up (image naming and versioning may differ depending on deploy configuration):

# docker ps --filter name=neutron_vpnaas_agent

CONTAINER ID   IMAGE                                                               COMMAND         CREATED          STATUS        PORTS  NAMES
97d25657d55e   operator:5000/kolla/oraclelinux-source-neutron-vpnaas-agent:4.0.0   "kolla_start"   44 minutes ago   Up 44 minutes        neutron_vpnaas_agent

Kolla-Ansible includes a small script that can be used in tandem with tools/init-runonce to verify the VPN using two routers and two Nova VMs:


Verify both VPN services are active:

# neutron vpn-service-list

| id                                   | name     | router_id                            | status |
| ad941ec4-5f3d-4a30-aae2-1ab3f4347eb1 | vpn_west | 051f7ce3-4301-43cc-bfbd-7ffd59af539e | ACTIVE |
| edce15db-696f-46d8-9bad-03d087f1f682 | vpn_east | 058842e0-1d01-4230-af8d-0ba6d0da8b1f | ACTIVE |

Two VMs can now be booted, one on vpn_east, the other on vpn_west, and encrypted ping packets observed being sent from one to the other.

For more information on this and VPNaaS in Neutron refer to the Neutron VPNaaS Testing and the OpenStack wiki.


Preparation and deployment

Modify the /etc/kolla/globals.yml file as the following example shows:

enable_opendaylight: "yes"

Networking-ODL is an additional Neutron plugin that allows the OpenDaylight SDN Controller to utilize its networking virtualization features. For OpenDaylight to work, the Networking-ODL plugin has to be installed in the neutron-server container. In this case, one could use the neutron-server-opendaylight container and the opendaylight container by pulling from Kolla dockerhub or by building them locally.

OpenDaylight globals.yml configurable options with their defaults include:

opendaylight_mechanism_driver: "opendaylight_v2"
opendaylight_l3_service_plugin: "odl-router_v2"
opendaylight_acl_impl: "learn"
enable_opendaylight_qos: "no"
enable_opendaylight_l3: "yes"
enable_opendaylight_legacy_netvirt_conntrack: "no"
opendaylight_port_binding_type: "pseudo-agentdb-binding"
opendaylight_features: "odl-mdsal-apidocs,odl-netvirt-openstack"
opendaylight_allowed_network_types: '"flat", "vlan", "vxlan"'

Clustered OpenDaylight Deploy

High availability clustered OpenDaylight requires modifying the inventory file and placing three or more hosts in the OpenDaylight or Networking groups.


The OpenDaylight role will allow deploy of one or three plus hosts for OpenDaylight/Networking role.


Verify the build and deploy operation of Networking-ODL containers. Successful deployment will bring up an Opendaylight container in the list of running containers on network/opendaylight node.

For the source code, please refer to the following link:



Open vSwitch (ovs) is an open source software virtual switch developed and distributed via The Data Plane Development Kit (dpdk) is a collection of userspace libraries and tools that facilitate the development of high-performance userspace networking applications.

As of the ovs 2.2 release, the ovs netdev datapath has supported integration with dpdk for accelerated userspace networking. As of the pike release of kolla support for deploying ovs with dpdk (ovs-dpdk) has been added to kolla ansible. The ovs-dpdk role introduced in the pike release has been tested on centos 7 and ubuntu 16.04 hosts, however, ubuntu is recommended due to conflicts with the cgroup configuration created by the default systemd version shipped with centos 7.


DPDK is a high-performance userspace networking library, as such it has several requirements to function correctly that are not required when deploying ovs without dpdk.

To function efficiently one of the mechanisms dpdk uses to accelerate memory access is the utilisation of kernel hugepages. The use of hugepage memory minimises the chance of a translation lookaside buffer(TLB) miss when translating virtual to physical memory as it increases the total amount of addressable memory that can be cached via the TLB. Hugepage memory pages are unswappable contiguous blocks of memory of typically 2MiB or 1GiB in size, that can be used to facilitate efficient sharing of memory between guests and a vSwitch or DMA mapping between physical nics and the userspace ovs datapath.

To deploy ovs-dpdk on a platform a proportion of system memory should be allocated hugepages. While it is possible to allocate hugepages at runtime it is advised to allocate them via the kernel command line instead to prevent memory fragmentation. This can be achieved by adding the following to the grub config and regenerating your grub file.

default_hugepagesz=2M hugepagesz=2M hugepages=25000

As dpdk is a userspace networking library it requires userspace compatible drivers to be able to control the physical interfaces on the platform. dpdk technically support 3 kernel drivers igb_uio,``uio_pci_generic``, and vfio_pci. While it is technically possible to use all 3 only uio_pci_generic and vfio_pci are recommended for use with kolla. igb_uio is BSD licenced and distributed as part of the dpdk library. While it has some advantages over uio_pci_generic loading the igb_uio module will taint the kernel and possibly invalidate distro support. To successfully deploy ovs-dpdk, vfio_pci or uio_pci_generic kernel module must be present on the platform. Most distros include vfio_pci or uio_pci_generic as part of the default kernel though on some distros you may need to install kernel-modules-extra or the distro equivalent prior to running kolla-ansible deploy.


To enable ovs-dpdk, add the following configuration to /etc/kolla/globals.yml file:

ovs_datapath: "netdev"
enable_ovs_dpdk: yes
enable_openvswitch: yes
tunnel_interface: "dpdk_bridge"
neutron_bridge_name: "dpdk_bridge"

Unlike standard Open vSwitch deployments, the interface specified by neutron_external_interface should have an ip address assigned. The ip address assigned to neutron_external_interface will be moved to the “dpdk_bridge” as part of deploy action. When using ovs-dpdk the tunnel_interface must be an ovs bridge with a physical interfaces attached for tunnelled traffic to be accelerated by dpdk. Note that due to a limitation in ansible variable names which excluded the use of - in a variable name it is not possible to use the default br-ex name for the neutron_bridge_name or tunnel_interface.

At present, the tunnel interface ip is configured using network manager on on ubuntu and systemd on centos family operating systems. systemd is used to work around a limitation of the centos network manager implementation which does not consider the creation of an ovs bridge to be a hotplug event. In the future, a new config option will be introduced to allow systemd to be used on all host distros for those who do not wish to enable the network manager service on ubuntu.


Reconfiguration from kernel ovs to ovs dpdk is currently not supported. Changing ovs datapaths on a deployed node requires neutron config changes and libvirt xml changes for all running instances including a hard reboot of the vm.

When upgrading ovs-dpdk it should be noted that this will always involve a dataplane outage. Unlike kernel OVS the dataplane for ovs-dpdk executes in the ovs-vswitchd process. This means the lifetime of the dpdk dataplane is tied to the lifetime of the ovsdpdk_vswitchd container. As such it is recommended to always evacuate all vm workloads from a node running ovs-dpdk prior to upgrading.

On ubuntu network manager is required for tunnel networking. This requirement will be removed in the future.

Neutron SRIOV

Preparation and deployment

SRIOV requires specific NIC and BIOS configuration and is not supported on all platforms. Consult NIC and platform specific documentation for instructions on enablement.

Modify the /etc/kolla/globals.yml file as the following example shows:

enable_neutron_sriov: "yes"

Modify the /etc/kolla/config/neutron/ml2_conf.ini file and add sriovnicswitch to the mechanism_drivers. Also, the provider networks used by SRIOV should be configured. Both flat and VLAN are configured with the same physical network name in this example:

mechanism_drivers = openvswitch,l2population,sriovnicswitch

network_vlan_ranges = sriovtenant1:1000:1009

flat_networks = sriovtenant1

Add PciPassthroughFilter to scheduler_default_filters

The PciPassthroughFilter, which is required by Nova Scheduler service on the Controller, should be added to scheduler_default_filters

Modify the /etc/kolla/config/nova.conf file and add PciPassthroughFilter to scheduler_default_filters. this filter is required by The Nova Scheduler service on the controller node.

scheduler_default_filters = <existing filters>, PciPassthroughFilter
scheduler_available_filters = nova.scheduler.filters.all_filters

Edit the /etc/kolla/config/nova.conf file and add PCI device whitelisting. this is needed by OpenStack Compute service(s) on the Compute.

passthrough_whitelist = [{"devname": "ens785f0", "physical_network": "sriovtenant1"}]

Modify the /etc/kolla/config/neutron/sriov_agent.ini file. Add physical network to interface mapping. Specific VFs can also be excluded here. Leaving blank means to enable all VFs for the interface:

physical_device_mappings = sriovtenant1:ens785f0
exclude_devices =

Run deployment.


Check that VFs were created on the compute node(s). VFs will appear in the output of both lspci and ip link show. For example:

# lspci | grep net
05:10.0 Ethernet controller: Intel Corporation 82599 Ethernet Controller Virtual Function (rev 01)

# ip -d link show ens785f0
4: ens785f0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master ovs-system state UP mode DEFAULT qlen 1000
link/ether 90:e2:ba:ba:fb:20 brd ff:ff:ff:ff:ff:ff promiscuity 1
openvswitch_slave addrgenmode eui64
vf 0 MAC 52:54:00:36:57:e0, spoof checking on, link-state auto, trust off
vf 1 MAC 52:54:00:00:62:db, spoof checking on, link-state auto, trust off
vf 2 MAC fa:16:3e:92:cf:12, spoof checking on, link-state auto, trust off
vf 3 MAC fa:16:3e:00:a3:01, vlan 1000, spoof checking on, link-state auto, trust off

Verify the SRIOV Agent container is running on the compute node(s):

# docker ps --filter name=neutron_sriov_agent
CONTAINER ID   IMAGE                                                                COMMAND        CREATED         STATUS         PORTS  NAMES
b03a8f4c0b80  "kolla_start"  18 minutes ago  Up 18 minutes         neutron_sriov_agent

Verify the SRIOV Agent service is present and UP:

# openstack network agent list

| ID                                   | Agent Type         | Host        | Availability Zone | Alive | State | Binary                    |
| 7c06bda9-7b87-487e-a645-cc6c289d9082 | NIC Switch agent   | av09-18-wcp | None              | :-)   | UP    | neutron-sriov-nic-agent   |

Create a new provider network. Set provider-physical-network to the physical network name that was configured in /etc/kolla/config/nova.conf. Set provider-network-type to the desired type. If using VLAN, ensure provider-segment is set to the correct VLAN ID. This example uses VLAN network type:

# openstack network create --project=admin \
  --provider-network-type=vlan \
  --provider-physical-network=sriovtenant1 \
  --provider-segment=1000 \

Create a subnet with a DHCP range for the provider network:

# openstack subnet create --network=sriovnet1 \
  --subnet-range= \
  --allocation-pool start=,end= \

Create a port on the provider network with vnic_type set to direct:

# openstack port create --network sriovnet1 --vnic-type=direct sriovnet1-port1

Start a new instance with the SRIOV port assigned:

# openstack server create --flavor flavor1 \
  --image fc-26 \
  --nic port-id=`openstack port list | grep sriovnet1-port1 | awk '{print $2}'` \

Verify the instance boots with the SRIOV port. Verify VF assignment by running dmesg on the compute node where the instance was placed.

# dmesg
[ 2896.849970] ixgbe 0000:05:00.0: setting MAC fa:16:3e:00:a3:01 on VF 3
[ 2896.850028] ixgbe 0000:05:00.0: Setting VLAN 1000, QOS 0x0 on VF 3
[ 2897.403367] vfio-pci 0000:05:10.4: enabling device (0000 -> 0002)

For more information see OpenStack SRIOV documentation.


Preparation and deployment

Nova provides a separate mechanism to attach PCI devices to instances that is independent from Neutron. Using the PCI alias configuration option in nova.conf, any PCI device (PF or VF) that supports passthrough can be attached to an instance. One major drawback to be aware of when using this method is that the PCI alias option uses a device’s product id and vendor id only, so in environments that have NICs with multiple ports configured for SRIOV, it is impossible to specify a specific NIC port to pull VFs from.

Modify the file /etc/kolla/config/nova.conf. The Nova Scheduler service on the control node requires the PciPassthroughFilter to be added to the list of filters and the Nova Compute service(s) on the compute node(s) need PCI device whitelisting. The Nova API service on the control node and the Nova Compute service on the compute node also require the alias option under the [pci] section. The alias can be configured as ‘type-VF’ to pass VFs or ‘type-PF’ to pass the PF. Type-VF is shown in this example:

scheduler_default_filters = <existing filters>, PciPassthroughFilter
scheduler_available_filters = nova.scheduler.filters.all_filters

passthrough_whitelist = [{"vendor_id": "8086", "product_id": "10fb"}]
alias = [{"vendor_id":"8086", "product_id":"10ed", "device_type":"type-VF", "name":"vf1"}]

Run deployment.


Create (or use an existing) flavor, and then configure it to request one PCI device from the PCI alias:

# openstack flavor set sriov-flavor --property "pci_passthrough:alias"="vf1:1"

Start a new instance using the flavor:

# openstack server create --flavor sriov-flavor --image fc-26 vm2

Verify VF devices were created and the instance starts successfully as in the Neutron SRIOV case.

For more information see OpenStack PCI passthrough documentation.

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