= Installing Open vSwitch on a node =
This page describes how to install Open vSwitch on a sandbox node. Open vSwitch is a software !OpenFlow switch implementation designed to run on a PC. More information about the software can be found [http://openvswitch.org/ here]. The docs provided online are a bit outdated at this point; The installation steps followed here is INSTALL.Linux, included with the Open vSwitch tarball (but attached to this page for your convenience).    

== 1.Prerequisites ==
The node used here is a NetFPGA cube, the standard node for !SandBox9. The node was imaged with ubuntu.ndz, based on Ubuntu 10.10 (Maverick). A few steps are needed before we begin fetching the install file or any of its dependencies. On the node:

1. In /etc/apt/sources.list, replace all instances of 'apt:9999' with 'us.archive.ubuntu.com'

2. Install packages for Open Vswitch:
{{{
apt-get update
apt-get install pkg-config autoconf automake linux-libc-dev libtool
}}}

3. Fetch and untar Open vSwitch (don't do anything to it yet):
{{{
cd ~/
wget http://openvswitch.org/releases/openvswitch-1.1.1.tar.gz
tar -xf openvswitch-1.1.1.tar.gz
}}} 

4. Upgrade the kernel to 2.6.35-30, as 2.6.35-25's kernel header packages are broken (otherwise '2.6.35-30-generic' in the following commands can be replaced with !`uname -r`). 
{{{
apt-get install linux-headers-2.6.35-30-generic linux-image-2.6.35-30-generic
reboot
apt-get install linux-source-2.6.35
}}}
When linux-image is installed, grub is updated so that the newest kernel is loaded automatically upon next reboot. Re-installing linux-source after reboot should install the proper version for the new kernel.

== 2. Installation == 
On Debian (and its variants), Open vSwitch must be built as a kernel module. If everything is sound, installing Open vSwitch should be little more than following the steps in INSTALL.Linux, found under the untarred Open vSwitch root directory.
{{{
cd ~/openvswitch-1.1.1
./boot.sh
./configure --with-l26=/lib/modules/`uname -r`/build
make
make install
}}}

== 2.1. Sanity checks ==
If things are not well, here are some things worth checking: 

1. Check /usr/src/linux-headers-!`uname -r`/.config for the following kernel configs:

 * CONFIG_BRIDGE as module (=m)
 * NET_CLS_ACT, NET_CLS_U32, NET_SCH_INGRESS as modules or built-in (=m or =y, respectively) if policing
 * CONFIG_TUN if you need tunneling

Fix them as necessary. 

2. The bridge module should not be loaded (e.g. should not show up when you do `lsmod | grep bridge`); remove it if it is loaded. If it seems to be loaded at boot time, there may be an entry for it somewhere in /etc/modules.

3. /lib/modules/$(uname -r)/build should be a link to the Linux kernel header directory:
{{{
root@node1-1:~# ls -ald /lib/modules/$(uname -r)/build
lrwxrwxrwx 1 root root 40 2011-07-26 13:41 /lib/modules/2.6.35-30-generic/build -> /usr/src/linux-headers-2.6.35-30-generic
}}}
This directory should contain (mostly) unbroken links. If not, repeat step 3 of the prerequisites with another kernel version. 

== References ==
The following links were referenced but aren't relevant overall; this is just for citation.

 * http://www.cyberciti.biz/tips/build-linux-kernel-module-against-installed-kernel-source-tree.html
 * http://forums.gentoo.org/viewtopic-t-118180-highlight-bridgeutils.html?sid=4d602c9e364130609caff99aa2a40c69
 * https://help.ubuntu.com/community/Kernel/Compile
 * http://ubuntuguide.net/ubuntu-11-04-upgrade-linux-kernel-to-2-6-39-0