nm-openvswitch: NetworkManager Reference Manual

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nm-openvswitch

nm-openvswitch — overview of NetworkManager Open vSwitch support

Overview

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.

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 - attached. -

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 - attached. Ports must be attached to a Bridge.

Interfaces

Interfaces are represented by a connections attached 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 attachment to a Port.

Examples

Example 20. 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.
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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 21. 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.
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Again, you need a port.

Example 22. 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.
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It's just a port with a tag.

Example 23. 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.
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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.

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Bugs

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

Probably many more.