How to Install Open vSwitch on Linux, FreeBSD and NetBSD ======================================================== This document describes how to build and install Open vSwitch on a generic Linux, FreeBSD, or NetBSD host. For specifics around installation on a specific platform, please see one of these files: - INSTALL.Debian - INSTALL.Fedora - INSTALL.RHEL - INSTALL.XenServer Build Requirements ------------------ To compile the userspace programs in the Open vSwitch distribution, you will need the following software: - GNU make. - A C compiler, such as: * GCC 4.x. * Clang. Clang 3.4 and later provide useful static semantic analysis and thread-safety checks. For Ubuntu, there are nightly built packages available on clang's website. - 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. If libssl is installed, then Open vSwitch will automatically build with support for it. To compile the kernel module on Linux, 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_BASIC, NET_SCH_INGRESS, and NET_ACT_POLICE, either built-in or as modules. (NET_CLS_POLICE is obsolete and not needed.) To use GRE tunneling on Linux 2.6.37 or newer, kernel support for GRE must be compiled in or available as a module (CONFIG_NET_IPGRE_DEMUX). To configure HTB or HFSC quality of service with Open vSwitch, you must enable the respective configuration options. To use Open vSwitch support for TAP devices, you must enable CONFIG_TUN. - 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 or the database schema, you will also need the following software: - Autoconf version 2.64 or later. - Automake version 1.10 or later. - Python 2.x, for x >= 4. If you modify the ovsdbmonitor tool, then you will also need the following: - pyuic4 from PyQt4 (http://www.riverbankcomputing.co.uk). To run the unit tests, you also need: - Perl. Version 5.10.1 is known to work. Earlier versions should also work. The ovs-vswitchd.conf.db(5) manpage will include an E-R diagram, in formats other than plain text, only if you have the following: - "dot" from graphviz (http://www.graphviz.org/). - Perl. Version 5.10.1 is known to work. Earlier versions should also work. - Python 2.x, for x >= 4. If you are going to extensively modify Open vSwitch, please consider installing the following to obtain better warnings: - "sparse" version 0.4.4 or later (http://www.kernel.org/pub/software/devel/sparse/dist/). - GNU make. - clang, version 3.4 or later Also, you may find the ovs-dev script found in utilities/ovs-dev.py useful. 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. - On Linux, the same kernel version configured as part of the build. - For optional support of ingress policing on Linux, the "tc" program from iproute2 (part of all major distributions and available at http://www.linux-foundation.org/en/Net:Iproute2). On Linux you should ensure that /dev/urandom exists. To support TAP devices, you must also ensure that /dev/net/tun exists. To run the ovsdbmonitor tool, the machine must also have the following software: - Python 2.x, for x >= 4. - Python Twisted Conch. - Python JSON. - PySide or PyQt4. - Python Zope interface module. (On Debian "lenny" the above can be installed with "apt-get install python-json python-qt4 python-zopeinterface python-twisted-conch".) Building and Installing Open vSwitch for Linux, FreeBSD or NetBSD ================================================================= 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 use 'clang' compiler: % ./configure CC=clang 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-linux. For example, to build for a running instance of Linux: % ./configure --with-linux=/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: % ./configure --with-linux=/path/to/linux 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 GNU make in the top source directory, e.g.: % make or if GNU make is installed as "gmake": % gmake For improved warnings if you installed "sparse" (see "Prerequisites"), add C=1 to the command line. 4. Consider running the testsuite. Refer to "Running the Testsuite" below, for instructions. 5. Become root by running "su" or another program. 6. Run "make install" to install the executables and manpages into the running system, by default under /usr/local. 7. If you built kernel modules, you may install and load them, e.g.: % make modules_install % /sbin/modprobe openvswitch To verify that the modules have been loaded, run "/sbin/lsmod" and check that openvswitch is listed. If the "modprobe" operation fails, look at the last few kernel log messages (e.g. with "dmesg | tail"): - The message "openvswitch: exports duplicate symbol br_should_route_hook (owned by bridge)" means that the bridge module is loaded. Run "/sbin/rmmod bridge" to remove it. If "/sbin/rmmod bridge" fails with "ERROR: Module bridge does not exist in /proc/modules", then the bridge is compiled into the kernel, rather than as a module. Open vSwitch does not support this configuration (see "Build Requirements", above). - The message "openvswitch: exports duplicate symbol dp_ioctl_hook (owned by ofdatapath)" means that the ofdatapath module from the OpenFlow reference implementation is loaded. Run "/sbin/rmmod ofdatapath" to remove it. (You might have to delete any existing datapaths beforehand, using the "dpctl" program included with the OpenFlow reference implementation. "ovs-dpctl" will not work.) - Otherwise, the most likely problem is that Open vSwitch was built for a kernel different from the one into which you are trying to load it. Run "modinfo" on openvswitch.ko and on a module built for the running kernel, e.g.: % /sbin/modinfo openvswitch.ko % /sbin/modinfo /lib/modules/`uname -r`/kernel/net/bridge/bridge.ko Compare the "vermagic" lines output by the two commands. If they differ, then Open vSwitch was built for the wrong kernel. - If you decide to report a bug or ask a question related to module loading, please include the output from the "dmesg" and "modinfo" commands mentioned above. There is an optional module parameter to openvswitch.ko called vlan_tso that enables TCP segmentation offload over VLANs on NICs that support it. Many drivers do not expose support for TSO on VLANs in a way that Open vSwitch can use but there is no way to detect whether this is the case. If you know that your particular driver can handle it (for example by testing sending large TCP packets over VLANs) then passing in a value of 1 may improve performance. Modules built for Linux kernels 2.6.37 and later, as well as specially patched versions of earlier kernels, do not need this and do not have this parameter. If you do not understand what this means or do not know if your driver will work, do not set this. 8. Initialize the configuration database using ovsdb-tool, e.g.: % mkdir -p /usr/local/etc/openvswitch % ovsdb-tool create /usr/local/etc/openvswitch/conf.db vswitchd/vswitch.ovsschema Startup ======= Before starting ovs-vswitchd itself, you need to start its configuration database, ovsdb-server. Each machine on which Open vSwitch is installed should run its own copy of ovsdb-server. Configure it to use the database you created during step 7 of installation, above, to listen on a Unix domain socket, to connect to any managers specified in the database itself, and to use the SSL configuration in the database: % ovsdb-server --remote=punix:/usr/local/var/run/openvswitch/db.sock \ --remote=db:Open_vSwitch,Open_vSwitch,manager_options \ --private-key=db:Open_vSwitch,SSL,private_key \ --certificate=db:Open_vSwitch,SSL,certificate \ --bootstrap-ca-cert=db:Open_vSwitch,SSL,ca_cert \ --pidfile --detach (If you built Open vSwitch without SSL support, then omit --private-key, --certificate, and --bootstrap-ca-cert.) Then initialize the database using ovs-vsctl. This is only necessary the first time after you create the database with ovsdb-tool (but running it at any time is harmless): % ovs-vsctl --no-wait init Then start the main Open vSwitch daemon, telling it to connect to the same Unix domain socket: % ovs-vswitchd --pidfile --detach Now you may use ovs-vsctl to set up bridges and other Open vSwitch features. For example, to create a bridge named br0 and add ports eth0 and vif1.0 to it: % ovs-vsctl add-br br0 % ovs-vsctl add-port br0 eth0 % ovs-vsctl add-port br0 vif1.0 Please refer to ovs-vsctl(8) for more details. Upgrading ========= When you upgrade Open vSwitch from one version to another, you should also upgrade the database schema: 1. Stop the Open vSwitch daemons, e.g.: % kill `cd /usr/local/var/run/openvswitch && cat ovsdb-server.pid ovs-vswitchd.pid` 2. Install the new Open vSwitch release. 3. Upgrade the database, in one of the following two ways: - If there is no important data in your database, then you may delete the database file and recreate it with ovsdb-tool, following the instructions under "Building and Installing Open vSwitch for Linux, FreeBSD or NetBSD". - If you want to preserve the contents of your database, back it up first, then use "ovsdb-tool convert" to upgrade it, e.g.: % ovsdb-tool convert /usr/local/etc/openvswitch/conf.db vswitchd/vswitch.ovsschema 4. Start the Open vSwitch daemons as described under "Building and Installing Open vSwitch for Linux, FreeBSD or NetBSD" above. Hot Upgrading ============= Upgrading Open vSwitch from one version to the next version with minimum disruption of traffic going through the system that is using that Open vSwitch needs some considerations: 1. If the upgrade only involves upgrading the userspace utilities and daemons of Open vSwitch, make sure that the new userspace version is compatible with the previously loaded kernel module. 2. An upgrade of userspace daemons means that they have to be restarted. Restarting the daemons means that the Openflow flows in the ovs-vswitchd daemon will be lost. One way to restore the flows is to let the controller re-populate it. Another way is to save the previous flows using a utility like ovs-ofctl and then re-add them after the restart. Restoring the old flows is accurate only if the new Open vSwitch interfaces retain the old 'ofport' values. 3. When the new userspace daemons get restarted, they automatically flush the old flows setup in the kernel. This can be expensive if there are hundreds of new flows that are entering the kernel but userspace daemons are busy setting up new userspace flows from either the controller or an utility like ovs-ofctl. Open vSwitch database provides an option to solve this problem through the other_config:flow-restore-wait column of the Open_vSwitch table. Refer to the ovs-vswitchd.conf.db(5) manpage for details. 4. If the upgrade also involves upgrading the kernel module, the old kernel module needs to be unloaded and the new kernel module should be loaded. This means that the kernel network devices belonging to Open vSwitch is recreated and the kernel flows are lost. The downtime of the traffic can be reduced if the userspace daemons are restarted immediately and the userspace flows are restored as soon as possible. The ovs-ctl utility's "restart" function only restarts the userspace daemons, makes sure that the 'ofport' values remain consistent across restarts, restores userspace flows using the ovs-ofctl utility and also uses the other_config:flow-restore-wait column to keep the traffic downtime to the minimum. The ovs-ctl utility's "force-reload-kmod" function does all of the above, but also replaces the old kernel module with the new one. Open vSwitch startup scripts for Debian, XenServer and RHEL use ovs-ctl's functions and it is recommended that these functions be used for other software platforms too. Running the Testsuite ===================== Open vSwitch includes a testsuite. Before you submit patches upstream, we advise that you run the tests and ensure that they pass. If you add new features to Open vSwitch, then adding tests for those features will ensure your features don't break as developers modify other areas of Open vSwitch. You must configure and build Open vSwitch (steps 1 through 3 in "Building and Installing Open vSwitch for Linux, FreeBSD or NetBSD" above) before you run the testsuite. You do not need to install Open vSwitch or to build or load the kernel module to run the testsuite. You do not need supervisor privilege to run the testsuite. To run all the unit tests in Open vSwitch, one at a time: make check This takes under 5 minutes on a modern desktop system. To run all the unit tests in Open vSwitch, up to 8 in parallel: make check TESTSUITEFLAGS=-j8 This takes under a minute on a modern 4-core desktop system. To see a list of all the available tests, run: make check TESTSUITEFLAGS=--list To run only a subset of tests, e.g. test 123 and tests 477 through 484: make check TESTSUITEFLAGS='123 477-484' (Tests do not have inter-dependencies, so you may run any subset.) To run tests matching a keyword, e.g. "ovsdb": make check TESTSUITEFLAGS='-k ovsdb' To see a complete list of test options: make check TESTSUITEFLAGS=--help The results of a testing run are reported in tests/testsuite.log. Please report test failures as bugs and include the testsuite.log in your report. If you have "valgrind" installed, then you can also run the testsuite under valgrind by using "make check-valgrind" in place of "make check". All the same options are available via TESTSUITEFLAGS. When you do this, the "valgrind" results for test are reported in files named tests/testsuite.dir//valgrind.*. You may find that the valgrind results are easier to interpret if you put "-q" in ~/.valgrindrc, since that reduces the amount of output. Sometimes a few tests may fail on some runs but not others. This is usually a bug in the testsuite, not a bug in Open vSwitch itself. If you find that a test fails intermittently, please report it, since the developers may not have noticed. Bug Reporting ------------- Please report problems to bugs@openvswitch.org.