Macvtap Mechanism Driver¶

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 Linux bridge: Self-service networks or Open vSwitch: Self-service networks 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.

Note

To support integration with the deployment examples, this content configures the Macvtap mechanism driver to use the overlay network for untagged (flat) or tagged (VLAN) networks in addition to overlay networks such as VXLAN. Your physical network infrastructure must support VLAN (802.1q) tagging on the overlay network.

Architecture¶

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

Macvtap mechanism driver - compute node components

Macvtap mechanism driver - compute node connectivity

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¶

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.
Restart the following services:
- Server

Network nodes¶

No changes.

Compute nodes¶

Install the Networking service Macvtap layer-2 agent.
In the neutron.conf file, configure common options:
```
[DEFAULT]
core_plugin = ml2
auth_strategy = keystone

[database]
# ...

[keystone_authtoken]
# ...

[nova]
# ...

[agent]
# ...
```
See the Installation Tutorials and Guides and Configuration Reference for your OpenStack release to obtain the appropriate additional configuration for the [DEFAULT], [database], [keystone_authtoken], [nova], and [agent] sections.
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.
Start the following services:
- Macvtap agent

Verify service operation¶

Source the administrative project credentials.

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.

Macvtap Mechanism Driver