nm-openvswitch: NetworkManager Reference Manual

+ + +

nm-openvswitch

nm-openvswitch — overview of NetworkManager OpenVSwitch support

Overview

NetworkManager includes basic OpenVSwitch support, good enough + to be capable of setting up simple OpenVSwitch configurations. It is not + extensive and does not expose all functionality of OpenVSwitch provides. + For large or complicated deployments users are advised to use native tools + shipped with OpenVSwitch. 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 enslaved to Ports, and Ports are always + enslaved 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 enslave 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.

Bridges

Bridges are represented by connections of ovs-bridge + type. + Due to the limitations of OVSDB, "empty" Bridges (with no Ports) can't exist. + NetworkManager inserts the records for Bridges into OVSDB when a Port is + enslaved. +

Ports

Ports are represented by connections of ovs-port + type. + Due to the limitations of OVSDB, "empty" Ports (with no Interfaces) can't + exist. Ports can also be configured to do VLAN tagging or Bonding. + NetworkManager inserts the records for Ports into OVSDB when an Interface is + enslaved. Ports must be enslaved to a Bridge.

Interfaces

Interfaces are represented by a connections enslaved to a Port. The + system interfaces (that have a corresponding Linux link) have a respective + connection.type + of the link (e.g. "wired", "bond", "dummy", etc.). Other interfaces ("internal" + or "patch" interfaces) are of ovs-interface type. The OVSDB entries are + inserted upon enslavement to a Port.

Examples

Example 14. Creating a Bridge with a single internal Interface

$ nmcli conn add conn.type ovs-bridge conn.interface bridge0
+Connection 'ovs-bridge-bridge0' (d10fc64d-1d48-4394-a1b8-e1aea72f27d5) successfully added.
+$ nmcli conn add conn.type ovs-port conn.interface port0 conn.master bridge0
+Connection 'ovs-port-port0' (5ae22bae-bba4-4815-9ade-7e635633e1f0) successfully added.
+$ nmcli conn add conn.type ovs-interface conn.interface iface0 conn.master 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 15. Adding a Linux interface to a Bridge

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

Again, you need a port.

Example 16. Creating a VLAN

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

It's just a port with a tag.

Example 17. Creating a Bond

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

It's just a Port with multiple interfaces. See nm-settings 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.

+
+

Bugs

Not all OpenVSwitch capabilities are supported.
OpenVSwitch devices don't expose many useful properties on D-Bus.

Probably many more.