The Macvtap mechanism driver for the ML2 plug-in generally increases
network performance of instances.

Consider the following attributes of this mechanism driver to
determine practicality in your environment:

• Supports only instance ports. Ports for DHCP and layer-3 (routing)
  services must use another mechanism driver such as Linux bridge or Open
  vSwitch (OVS).
• Supports only untagged (flat) and tagged (VLAN) networks.
• Lacks support for security groups including basic (sanity) and
  anti-spoofing rules.
• Lacks support for layer-3 high-availability mechanisms such as
  Virtual Router Redundancy Protocol (VRRP) and Distributed Virtual
  Routing (DVR).
• Only compute resources can be attached via macvtap. Attaching other
  resources like DHCP, Routers and others is not supported. Therefore run
  either OVS or linux bridge in VLAN or flat mode on the controller
  node.
• Instance migration requires the same values for the
  physical_interface_mapping configuration option on each
  compute node. For more information, see https://bugs.launchpad.net/neutron/+bug/1550400.

Prerequisites

You can add this mechanism driver to an existing environment using
either the Linux bridge or OVS mechanism drivers with only provider
networks or provider and self-service networks. You can change the
configuration of existing compute nodes or add compute nodes with the
Macvtap mechanism driver. The example configuration assumes addition of
compute nodes with the Macvtap mechanism driver to the deploy-lb-selfservice or
deploy-ovs-selfservice
deployment examples.

Add one or more compute nodes with the following components:

• Three network interfaces: management, provider, and overlay.
• OpenStack Networking Macvtap layer-2 agent and any
  dependencies.

Architecture

The Macvtap mechanism driver only applies to compute nodes.
Otherwise, the environment resembles the prerequisite deployment
example.

Example configuration

Use the following example configuration as a template to add support
for the Macvtap mechanism driver to an existing operational
environment.

Controller node

1. In the ml2_conf.ini file:

   • Add macvtap to mechanism drivers.

     [ml2]
     mechanism_drivers = macvtap

   • Configure network mappings.

     [ml2_type_flat]
     flat_networks = provider,macvtap
     
     [ml2_type_vlan]
     network_vlan_ranges = provider,macvtap:VLAN_ID_START:VLAN_ID_END

     Note

     Use of macvtap is arbitrary. Only the self-service
     deployment examples require VLAN ID ranges. Replace
     VLAN_ID_START and VLAN_ID_END with appropriate
     numerical values.

2. Restart the following services:
   • Server

Network nodes

No changes.

Compute nodes

1. Install the Networking service Macvtap layer-2 agent.

2. In the neutron.conf file, configure common
   options:

3. In the macvtap_agent.ini file, configure the layer-2
   agent.

   [macvtap]
   physical_interface_mappings = macvtap:MACVTAP_INTERFACE
   
   [securitygroup]
   firewall_driver = noop

   Replace MACVTAP_INTERFACE with the name of the
   underlying interface that handles Macvtap mechanism driver interfaces.
   If using a prerequisite deployment example, replace
   MACVTAP_INTERFACE with the name of the underlying interface
   that handles overlay networks. For example, eth1.

4. Start the following services:

   • Macvtap agent

Verify service operation

1. Source the administrative project credentials.

2. Verify presence and operation of the agents:

   $ openstack network agent list
   +--------------------------------------+--------------------+----------+-------------------+-------+-------+---------------------------+
   | ID                                   | Agent Type         | Host     | Availability Zone | Alive | State | Binary                    |
   +--------------------------------------+--------------------+----------+-------------------+-------+-------+---------------------------+
   | 31e1bc1b-c872-4429-8fc3-2c8eba52634e | Metadata agent     | compute1 | None              | True  | UP    | neutron-metadata-agent    |
   | 378f5550-feee-42aa-a1cb-e548b7c2601f | Open vSwitch agent | compute1 | None              | True  | UP    | neutron-openvswitch-agent |
   | 7d2577d0-e640-42a3-b303-cb1eb077f2b6 | L3 agent           | compute1 | nova              | True  | UP    | neutron-l3-agent          |
   | d5d7522c-ad14-4c63-ab45-f6420d6a81dd | Metering agent     | compute1 | None              | True  | UP    | neutron-metering-agent    |
   | e838ef5c-75b1-4b12-84da-7bdbd62f1040 | DHCP agent         | compute1 | nova              | True  | UP    | neutron-dhcp-agent        |
   +--------------------------------------+--------------------+----------+-------------------+-------+-------+---------------------------+

Create initial networks

This mechanism driver simply changes the virtual network interface
driver for instances. Thus, you can reference the
Create initial networks content for the prerequisite
deployment example.

Verify network operation

This mechanism driver simply changes the virtual network interface
driver for instances. Thus, you can reference the
Verify network operation content for the prerequisite
deployment example.

Network traffic flow

This mechanism driver simply removes the Linux bridge handling
security groups on the compute nodes. Thus, you can reference the
network traffic flow scenarios for the prerequisite deployment
example.