nm-openvswitch - Man Page

NetworkManager includes basic Open vSwitch support, good enough to be capable of setting up simple Open vSwitch configurations​. It is not extensive and does not expose all functionality of Open vSwitch provides​. For large or complicated deployments users are advised to use native tools shipped with Open vSwitch​. This document seeks to provide overview of functionality currently provided by NetworkManager, its capabilities and limitations​.

First and foremost: NetworkManager applies the configuration by modifying the OVSDB directly​. Its configuration model follows the OVSDB database model closely and it does not provide the level of abstraction ovs-vsctl provides​.

In practical terms it means the following:

• NetworkManager only ever talks to a single OVSDB instance via an UNIX domain socket​.
• The configuration is made up of Bridges, Ports and Interfaces​. Interfaces are always attached to Ports, and Ports are always attached to Bridges​.
• NetworkManager only creates Bridges, Ports and Interfaces you ask it to​. Unlike ovs-vsctl, it doesn't create the local interface nor its port automatically​.
• You can't attach Interface directly to a Bridge​. You always need a Port, even if it has just one interface​.
• There are no VLANs​. The VLAN tagging is enabled by setting a ovs-port​.tag property on a Port​.
• There are no bonds either​. The bonding is enabled by enslaving multiple Interfaces to a Port and configured by setting properties on a port​.

Example ​1. ​Creating a Bridge with a single internal Interface

$ nmcli conn add type ovs-bridge conn​.interface bridge0
Connection 'ovs-bridge-bridge0' (d10fc64d-1d48-4394-a1b8-e1aea72f27d5) successfully added​.
$ nmcli conn add type ovs-port conn​.interface port0 controller bridge0
Connection 'ovs-port-port0' (5ae22bae-bba4-4815-9ade-7e635633e1f0) successfully added​.
$ nmcli conn add type ovs-interface port-type ovs-port conn​.interface iface0 \
  controller port0 ipv4​.method manual ipv4​.address 192​.0​.2​.1/24
Connection 'ovs-interface-iface0' (3640d2a1-a2fd-4718-92f1-cffadb5b6cdc) successfully added​.

As said above, you need to create a Port even for a single interface​. Also, before you add the Interface, the Bridge and Port devices appear active, but are not configured in OVSDB yet​. You can inspect the results with ovs-vsctl show​.

Example ​2. ​Adding a Linux interface to a Bridge

$ nmcli conn add type ovs-port conn​.interface port1 controller bridge0
Connection 'ovs-port-port1' (67d041eb-8e7b-4458-afee-a1d07c9c4552) successfully added​.
$ nmcli conn add type ethernet conn​.interface eth0 controller port1
Connection 'ovs-slave-eth0' (d459c45c-cf78-4c1c-b4b7-505e71379624) successfully added​.

Again, you need a port​.

Example ​3. ​Creating a VLAN

$ nmcli conn add type ovs-port conn​.interface port2 controller bridge0 ovs-port​.tag 120
Connection 'ovs-port-port2' (3994c093-4ef7-4549-a4fd-627b831c3cb8) successfully added​.
$ nmcli conn add type ethernet conn​.interface eth1 controller port2
Connection 'ovs-slave-eth1' (099be06e-71ad-484d-8d5a-fcadc5f207f5) successfully added​.

It's just a port with a tag​.

Example ​4. ​Creating a Bond

$ nmcli conn add type ovs-port conn​.interface bond0 controller bridge0
Connection 'ovs-port-bond0' (d154ebf9-e999-4e1b-a084-a3de53d25d8a) successfully added​.
$ nmcli conn add type ethernet conn​.interface eth2 controller bond0
Connection 'ovs-slave-eth2' (475ac1bf-30b2-4534-a877-27f33f58b082) successfully added​.
$ nmcli conn add type ethernet conn​.interface eth3 controller bond0
Connection 'ovs-slave-eth3' (8dedeecb-ed12-482b-b77a-24a4fb835136) successfully added​.

It's just a Port with multiple interfaces​. See nm-settings-nmcli manual for Bonding options you can use with "nmcli c add" or "nmcli c modify"​. You could even set a VLAN tag on the same Port to do VLAN tagging and bonding at the same time​.

• Not all Open vSwitch capabilities are supported​.
• Open vSwitch devices don't expose many useful properties on D-Bus​.

Probably many more​.

RFC 7047: The Open vSwitch Database Management Protocol​^[1], ovs-vsctl(8), ovs-vswitchd.conf.db(5), nm-settings-nmcli(5), nmcli(1)

1.

RFC 7047: The Open vSwitch Database Management Protocol
https://www.rfc-editor.org/rfc/rfc7047.txt