openvswitch/INSTALL.Linux

                 How to Install Open vSwitch on Linux
                 ====================================

This document describes how to build and install Open vSwitch on a
generic Linux host.  If you want to install Open vSwitch on a Citrix
XenServer version 5.5.0, see INSTALL.XenServer instead.

This version of Open vSwitch should be built manually with "configure"
and "make".  Debian packaging for Open vSwitch is also included, but
they have not been recently tested, and so Debian packages are not a
recommended way to use this version of Open vSwitch.

Build Requirements
------------------

To compile the userspace programs in the Open vSwitch distribution,
you will need the following software:

    - A make program, e.g. GNU make.  BSD make should also work.

    - The GNU C compiler.  We generally test with version 4.1, 4.2, or
      4.3.

    - libssl, from OpenSSL, is optional but recommended if you plan to
      connect the Open vSwitch to an OpenFlow controller.  libssl is
      required to establish confidentiality and authenticity in the
      connections from an Open vSwitch to an OpenFlow controller.  To
      enable, configure with --enable-ssl=yes.

To compile the kernel module, you must also install the following.  If
you cannot build or install the kernel module, you may use the
userspace-only implementation, at a cost in performance.  The
userspace implementation may also lack some features.  Refer to
INSTALL.userspace for more information.

    - A supported Linux kernel version.  Please refer to README for a
      list of supported versions.

      The Open vSwitch datapath requires bridging support
      (CONFIG_BRIDGE) to be built as a kernel module.  (This is common
      in kernels provided by Linux distributions.)  The bridge module
      must not be loaded or in use.  If the bridge module is running
      (check with "lsmod | grep bridge"), you must remove it ("rmmod
      bridge") before starting the datapath.

      For optional support of ingress policing, you must enable kernel
      configuration options NET_CLS_ACT, NET_CLS_U32, NET_SCH_INGRESS,
      and NET_ACT_POLICE, either built-in or as modules.
      (NET_CLS_POLICE is obsolete and not needed.)

    - To build a kernel module, you need the same version of GCC that
      was used to build that kernel.

    - A kernel build directory corresponding to the Linux kernel image
      the module is to run on.  Under Debian and Ubuntu, for example,
      each linux-image package containing a kernel binary has a
      corresponding linux-headers package with the required build
      infrastructure.

If you are working from a Git tree or snapshot (instead of from a
distribution tarball), or if you modify the Open vSwitch build system,
you will also need the following software:

    - Autoconf version 2.63 or later.

    - Automake version 1.10 or later.

    - pkg-config.  We test with version 0.22.

    - Python 2.x, for x >= 4.

Installation Requirements
-------------------------

The machine on which Open vSwitch is to be installed must have the
following software:

    - libc compatible with the libc used for build.

    - libssl compatible with the libssl used for build, if OpenSSL was
      used for the build.

    - The Linux kernel version configured as part of the build.

    - For optional support of ingress policing, the "tc" program from
      iproute2 (part of all major distributions and available at
      http://www.linux-foundation.org/en/Net:Iproute2).

    - For debugging purposes, Open vSwitch expects that "tcpdump" is
      installed as /usr/sbin/tcpdump.  If tcpdump is not installed, or
      if it is installed in a different location, then some Open
      vSwitch log messages will not be as detailed.

Building and Installing Open vSwitch for Linux
==============================================

Once you have installed all the prerequisites listed above in the Base
Prerequisites section, follow the procedure below to build.

1. If you pulled the sources directly from an Open vSwitch Git tree, 
   run boot.sh in the top source directory:

      % ./boot.sh

2. In the top source directory, configure the package by running the
   configure script.  You can usually invoke configure without any
   arguments:

      % ./configure

   By default all files are installed under /usr/local.  If you want
   to install into, e.g., /usr and /var instead of /usr/local and
   /usr/local/var, add options as shown here:

      % ./configure --prefix=/usr --localstatedir=/var

   To use a specific C compiler for compiling Open vSwitch user
   programs, also specify it on the configure command line, like so:

      % ./configure CC=gcc-4.2

   To build the Linux kernel module, so that you can run the
   kernel-based switch, pass the location of the kernel build
   directory on --with-l26.  For example, to build for a running
   instance of Linux 2.6:

      % ./configure --with-l26=/lib/modules/`uname -r`/build

   If you wish to build the kernel module for an architecture other
   than the architecture of the machine used for the build, you may
   specify the kernel architecture string using the KARCH variable
   when invoking the configure script.  For example, to build for MIPS
   with Linux 2.6:

      % ./configure --with-l26=/path/to/linux-2.6 KARCH=mips

   The configure script accepts a number of other options and honors
   additional environment variables.  For a full list, invoke
   configure with the --help option.

3. Run make in the top source directory: 

      % make

4. Become root by running "su" or another program.

5. Run "make install" to install the executables and manpages into the
   running system, by default under /usr/local.

6. If you built kernel modules, you may load them with "insmod", e.g.:

      % insmod datapath/linux-2.6/openvswitch_mod.ko

   You may need to specify a full path to insmod, e.g. /sbin/insmod.
   To verify that the modules have been loaded, run "/sbin/lsmod" and
   check that openvswitch_mod is listed.

Configuration
=============

Open vSwitch is configured primarily through a configuration file,
whose name is specified on the ovs-vswitchd command line.  Please
refer to ovs-vswitchd(8) and ovs-vswitchd.conf(5) for information on
how to start ovs-vswitchd and the syntax of its configuration file,
respectively.

At runtime, you may make ovs-vswitchd reload its configuration file
and update its configuration accordingly by sending it a SIGHUP
signal.  The ovs-appctl utility can also be used to do this:

    % ovs-appctl vswitchd/reload

In the latter case, ovs-appctl will wait for ovs-vswitchd to finish
reloading before it exits.

Bug Reporting
-------------

Please report problems to bugs@openvswitch.org.