kolla-ansible/doc/source/reference/networking-guide.rst

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 configuration file /etc/kolla/globals.yml:

enable_neutron_provider_networks: "yes"

Enabling Neutron Extensions

Overview

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

Networking-SFC

Preparation and deployment

Modify the configuration file /etc/kolla/globals.yml and change the following:

enable_neutron_sfc: "yes"

Verification

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 configuration file /etc/kolla/globals.yml and change the following:

enable_neutron_vpnaas: "yes"

Verification

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:

tools/init-runonce
tools/init-vpn

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 VPNaaS area on the OpenStack wiki:

https://wiki.openstack.org/wiki/Neutron/VPNaaS/HowToInstall https://wiki.openstack.org/wiki/Neutron/VPNaaS

Networking-ODL

Preparation and deployment

Modify the configuration file /etc/kolla/globals.yml and enable the following:

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_release: "0.6.1-Carbon"
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. Note: The OpenDaylight role will allow deploy of one or three plus hosts for OpenDaylight/Networking role.

Verification

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:

https://github.com/openstack/networking-odl

OVS with DPDK

Introduction

Open vSwitch (ovs) is an open source software virtual switch developed and distributed via openvswitch.org. 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.

Prerequisites

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.

Install

To enable ovs-dpdk add the following to /etc/kolla/globals.yml

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.

Limitations

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.