documentation: Add INSTALL.Libvirt file

Add documentation on how to use OVS integration
with the upcoming Libvirt 0.9.11 release.

Signed-off-by: Ansis Atteka <aatteka@nicira.com>

Author: Ansis Atteka

INSTALL.Libvirt

@@ -0,0 +1,72 @@
+                 How to Use Open vSwitch with Libvirt
+                 ====================================
+
+This document describes how to use Open vSwitch with Libvirt 0.9.11 or
+later. The Open vSwitch support in Libvirt 0.9.11 eliminates the need to
+use OVS Linux Bridge compatibility layer (brcompatd) and interface up/down
+scripts. This document assumes that you followed INSTALL.Linux or installed
+Open vSwitch from distribution packaging such as a .deb or .rpm. The Open
+vSwitch support is included by default in Libvirt 0.9.11. Consult
+www.libvirt.org for instructions on how to build the latest Libvirt, if your
+Linux distribution by default comes with an older Libvirt release.
+
+Limitations
+-----------
+Currently there is no Open vSwitch support for networks that are managed
+by libvirt (e.g. NAT). As of now, only bridged networks are supported (those
+where the user has to manually create the bridge).
+
+Setup
+-----
+
+First, create the Open vSwitch bridge by using the ovs-vsctl utility (this
+must be done with administrative privileges):
+
+ % ovs-vsctl add-br ovsbr
+
+Once that is done, create a VM, if necessary, and edit its Domain XML file:
+
+ % virsh edit <vm>
+
+Lookup in the Domain XML file the <interface> section. There should be one
+such XML section for each interface the VM has.
+
+ ...
+ <interface type='network'>
+  <mac address='52:54:00:71:b1:b6'/>
+  <source network='default'/>
+  <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
+ </interface>
+ ...
+
+And change it to something like this:
+
+ ...
+ <interface type='bridge'>
+  <mac address='52:54:00:71:b1:b6'/>
+  <source bridge='ovsbr'/>
+  <virtualport type='openvswitch'/>
+  <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
+ </interface>
+ ...
+
+The interface type must be set to "bridge". The <source> XML element
+specifies to which bridge this interface will be attached to. The
+<virtualport> element indicates that the bridge in <source> element is an
+Open vSwitch bridge.
+
+Then (re)start the VM and verify if the guest's vnet interface is attached to
+the ovsbr bridge.
+
+ % ovs-vsctl show
+
+Troubleshooting
+---------------
+If the VM does not want to start, then try to run the libvirtd process either
+from the terminal, so that all errors are printed in console, or inspect
+Libvirt/Open vSwitch log files for possible root cause.
+
+Bug Reporting
+-------------
+
+Please report problems to bugs@openvswitch.org.

Makefile.am

@@ -34,6 +34,7 @@ EXTRA_DIST = \
 	CodingStyle \
 	DESIGN \
 	INSTALL.KVM \
+	INSTALL.Libvirt \
 	INSTALL.Linux \
 	INSTALL.RHEL \
 	INSTALL.SSL \

README

@@ -102,6 +102,8 @@ Linux host, read INSTALL.RHEL.
 To use Open vSwitch with KVM on Linux, read INSTALL.Linux, then
 INSTALL.KVM.
 
+To use Open vSwitch with Libvirt, read INSTALL.Libvirt.
+
 To install Open vSwitch without using a kernel module, read
 INSTALL.userspace.