os-vif/doc/source/user/plugins/ovs.rst

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============
Open vSwitch
============
The Open vSwitch plugin, `vif_plug_ovs`, is an `os-vif` VIF plugin for the Open
vSwitch network backend. It is one of three plugins provided as part of `os-vif`
itself, the others being :doc:`linux-bridge` and :doc:`noop`.
Supported VIF Types
-------------------
The Open vSwitch plugin provides support for the following VIF types:
`VIFOpenVSwitch`
Configuration where a guest is directly connected an Open vSwitch bridge.
Refer to :ref:`vif-openvswitch` for more information.
`VIFBridge`
Configuration where a guest is connected to a Linux bridge via a TAP device,
and that bridge is connected to the Open vSwitch bridge. This allows for the
use of ``iptables`` rules for filtering traffic.
Refer to :ref:`vif-bridge` for more information.
`VIFVHostUser`
Configuration where a guest exposes a UNIX socket for its control plane. This
configuration is used with the `DPDK datapath of Open vSwitch`__.
Refer to :ref:`vif-vhostuser` for more information.
`VIFHostDevice`
Configuration where an :term:`SR-IOV` PCI device :term:`VF` is passed through
to a guest. The ``hw-tc-offload`` feature should be enabled on the SR-IOV
:term:`PF` using ``ethtool``:
.. code-block:: shell
ethtool -K <PF> hw-tc-offload
This will create a *VF representor* per VF. The VF representor plays the same
role as TAP devices in Para-Virtual (PV) setup. In this case the ``plug()``
method connects the VF representor to the OpenVSwitch bridge.
.. important::
Support for this feature requires Linux Kernel >= 4.8 and Open vSwitch
2.8. These add support for :term:`tc`-based hardware offloads for SR-IOV
VFs and offloading of OVS datapath rules using tc, respectively.
Refer to :ref:`vif-hostdevice` for more information.
.. versionadded:: 1.5.0
For information on the VIF type objects, refer to :doc:`/user/vif-types`. Note
that only the above VIF types are supported by this plugin.
__ http://docs.openvswitch.org/en/latest/howto/dpdk/