It is possible to test Open vSwitch using both tooling provided with Open vSwitch and using a variety of third party tooling.

Built-in Tooling

Open vSwitch provides a number of different test suites and other tooling for validating basic functionality of OVS. Before running any of the tests described here, you must bootstrap, configure and build Open vSwitch as described in Open vSwitch on Linux, FreeBSD and NetBSD. You do not need to install Open vSwitch or to build or load the kernel module to run these test suites. You do not need supervisor privilege to run these test suites.

Unit Tests

Open vSwitch includes a suite of self-tests. 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.

To run all the unit tests in Open vSwitch, one at a time, run:

$ make check

This takes under 5 minutes on a modern desktop system.

To run all the unit tests in Open vSwitch in parallel, run:

$ make check TESTSUITEFLAGS=-j8

You can run up to eight threads. 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, run:

$ 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, run:

$ make check TESTSUITEFLAGS='-k ovsdb'

To see a complete list of test options, run:

$ make check TESTSUITEFLAGS=--help

The results of a testing run are reported in tests/testsuite.log. Report test failures as bugs and include the testsuite.log in your report.


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. You can make the testsuite automatically rerun tests that fail, by adding RECHECK=yes to the make command line, e.g.:

$ make check TESTSUITEFLAGS=-j8 RECHECK=yes

Debugging unit tests

To initiate debugging from artifacts generated from make check run, set the OVS_PAUSE_TEST environment variable to 1. For example, to run test case 139 and pause on error:

$ OVS_PAUSE_TEST=1 make check TESTSUITEFLAGS='-v 139'

When error occurs, above command would display something like this:

Set environment variable to use various ovs utilities
export OVS_RUNDIR=<dir>/ovs/_build-gcc/tests/testsuite.dir/0139
Press ENTER to continue:

And from another window, one can execute ovs-xxx commands like:

export OVS_RUNDIR=/opt/vdasari/Developer/ovs/_build-gcc/tests/testsuite.dir/0139
$ ovs-ofctl dump-ports br0

Once done with investigation, press ENTER to perform cleanup operation.


If the build was configured with --enable-coverage and the lcov utility is installed, you can run the testsuite and generate a code coverage report by using the check-lcov target:

$ make check-lcov

All the same options are available via TESTSUITEFLAGS. For example:

$ make check-lcov TESTSUITEFLAGS='-j8 -k ovsdb'


If you have valgrind installed, you can run the testsuite under valgrind by using the check-valgrind target:

$ make check-valgrind

When you do this, the “valgrind” results for test <N> are reported in files named tests/testsuite.dir/<N>/valgrind.*.

To test the testsuite of kernel datapath under valgrind, you can use the check-kernel-valgrind target and find the “valgrind” results under directory tests/system-kmod-testsuite.dir/.

All the same options are available via TESTSUITEFLAGS.


You may find that the valgrind results are easier to interpret if you put -q in ~/.valgrindrc, since that reduces the amount of output.


OFTest is an OpenFlow protocol testing suite. Open vSwitch includes a Makefile target to run OFTest with Open vSwitch in “dummy mode”. In this mode of testing, no packets travel across physical or virtual networks. Instead, Unix domain sockets stand in as simulated networks. This simulation is imperfect, but it is much easier to set up, does not require extra physical or virtual hardware, and does not require supervisor privileges.

To run OFTest with Open vSwitch, you must obtain a copy of OFTest and install its prerequisites. You need a copy of OFTest that includes commit 406614846c5 (make ovs-dummy platform work again). This commit was merged into the OFTest repository on Feb 1, 2013, so any copy of OFTest more recent than that should work. Testing OVS in dummy mode does not require root privilege, so you may ignore that requirement.

Optionally, add the top-level OFTest directory (containing the oft program) to your $PATH. This slightly simplifies running OFTest later.

To run OFTest in dummy mode, run the following command from your Open vSwitch build directory:

$ make check-oftest OFT=<oft-binary>

where <oft-binary> is the absolute path to the oft program in OFTest. If you added “oft” to your $PATH, you may omit the OFT variable assignment

By default, check-oftest passes oft just enough options to enable dummy mode. You can use OFTFLAGS to pass additional options. For example, to run just the basic.Echo test instead of all tests (the default) and enable verbose logging, run:

$ make check-oftest OFT=<oft-binary> OFTFLAGS='--verbose -T basic.Echo'

If you use OFTest that does not include commit 4d1f3eb2c792 (oft: change default port to 6653), merged into the OFTest repository in October 2013, then you need to add an option to use the IETF-assigned controller port:

$ make check-oftest OFT=<oft-binary> OFTFLAGS='--port=6653'

Interpret OFTest results cautiously. Open vSwitch can fail a given test in OFTest for many reasons, including bugs in Open vSwitch, bugs in OFTest, bugs in the “dummy mode” integration, and differing interpretations of the OpenFlow standard and other standards.


Open vSwitch has not been validated against OFTest. Report test failures that you believe to represent bugs in Open vSwitch. Include the precise versions of Open vSwitch and OFTest in your bug report, plus any other information needed to reproduce the problem.


Ryu is an OpenFlow controller written in Python that includes an extensive OpenFlow testsuite. Open vSwitch includes a Makefile target to run Ryu in “dummy mode”. See OFTest above for an explanation of dummy mode.

To run Ryu tests with Open vSwitch, first read and follow the instructions under Testing above. Second, obtain a copy of Ryu, install its prerequisites, and build it. You do not need to install Ryu (some of the tests do not get installed, so it does not help).

To run Ryu tests, run the following command from your Open vSwitch build directory:

$ make check-ryu RYUDIR=<ryu-source-dir>

where <ryu-source-dir> is the absolute path to the root of the Ryu source distribution. The default <ryu-source-dir> is $srcdir/../ryu where $srcdir is your Open vSwitch source directory. If this is correct, omit RYUDIR


Open vSwitch has not been validated against Ryu. Report test failures that you believe to represent bugs in Open vSwitch. Include the precise versions of Open vSwitch and Ryu in your bug report, plus any other information needed to reproduce the problem.

Datapath testing

Open vSwitch includes a suite of tests specifically for datapath functionality, which can be run against the userspace or kernel datapaths. If you are developing datapath features, it is recommended that you use these tests and build upon them to verify your implementation.

The datapath tests make some assumptions about the environment. They must be run under root privileges on a Linux system with support for network namespaces. For ease of use, the OVS source tree includes a vagrant box to invoke these tests. Running the tests inside Vagrant provides kernel isolation, protecting your development host from kernel panics or configuration conflicts in the testsuite. If you wish to run the tests without using the vagrant box, there are further instructions below.



Requires Vagrant (version 1.7.0 or later) and a compatible hypervisor


You must bootstrap and configure the sources (see doc:/intro/install/general) before you run the steps described here.

A Vagrantfile is provided allowing to compile and provision the source tree as found locally in a virtual machine using the following command:

$ vagrant up

This will bring up a Fedora 23 VM by default. If you wish to use a different box or a vagrant backend not supported by the default box, the Vagrantfile can be modified to use a different box as base.

The VM can be reprovisioned at any time:

$ vagrant provision

OVS out-of-tree compilation environment can be set up with:

$ ./boot.sh
$ vagrant provision --provision-with configure_ovs,build_ovs

This will set up an out-of-tree build environment inside the VM in /root/build. The source code can be found in /vagrant.

To recompile and reinstall OVS in the VM using RPM:

$ ./boot.sh
$ vagrant provision --provision-with configure_ovs,install_rpm

Two provisioners are included to run system tests with the OVS kernel module or with a userspace datapath. This tests are different from the self-tests mentioned above. To run them:

$ ./boot.sh
$ vagrant provision --provision-with \

The results of the testsuite reside in the VM root user’s home directory:

$ vagrant ssh
$ sudo -s
$ cd /root/build
$ ls tests/system*


The datapath testsuite as invoked by Vagrant above may also be run manually on a Linux system with root privileges. Make sure, no other Open vSwitch instance is running on the test suite. These tests may take several minutes to complete, and cannot be run in parallel.

Userspace datapath

To invoke the datapath testsuite with the userspace datapath, run:

$ make check-system-userspace

The results of the testsuite are in tests/system-userspace-testsuite.dir.

All the features documented under Unit Tests are available for the userspace datapath testsuite.

Userspace datapath with DPDK

To test Open vSwitch with DPDK (i.e., the build was configured with --with-dpdk, the DPDK is installed), run the testsuite and generate a report by using the check-dpdk target:

# make check-dpdk

or if you are not a root, but a sudo user:

$ sudo -E make check-dpdk

To see a list of all the available tests, run:

# make check-dpdk TESTSUITEFLAGS=--list

These tests support a DPDK supported NIC. The tests operate on a wider set of environments, for instance, when a virtual port is used. Moreover you need to have root privileges to load the required modules and to bind a PCI device to the DPDK-compatible driver.

The phy test will skip if no suitable PCI device is found. It is possible to select which PCI device is used for this test by setting the DPDK_PCI_ADDR environment variable, which is especially useful when testing with a mlx5 device:

# DPDK_PCI_ADDR=0000:82:00.0 make check-dpdk

All tests are skipped if no hugepages are configured. User must look into the DPDK manual to figure out how to Configure hugepages.

All the features documented under Unit Tests are available for the DPDK testsuite.

Userspace datapath: Testing and Validation of CPU-specific Optimizations

As multiple versions of the datapath classifier, packet parsing functions and actions can co-exist, each with different CPU ISA optimizations, it is important to validate that they all give the exact same results. To easily test all the implementations, an autovalidator implementation of them exists. This implementation runs all other available implementations, and verifies that the results are identical.

Running the OVS unit tests with the autovalidator enabled ensures all implementations provide the same results. Note that the performance of the autovalidator is lower than all other implementations, as it tests the scalar implementation against itself, and against all other enabled implementations.

To adjust the autovalidator priority for a datapath classifier, use this command:

$ ovs-appctl dpif-netdev/subtable-lookup-prio-set autovalidator 7

To set the autovalidator for the packet parser, use this command:

$ ovs-appctl dpif-netdev/miniflow-parser-set autovalidator

To set the autovalidator for actions, use this command:

$ ovs-appctl odp-execute/action-impl-set autovalidator

To run the OVS unit test suite with the autovalidator as the default implementation, it is required to recompile OVS. During the recompilation, the default priority of the autovalidator implementation is set to the maximum priority, ensuring every test will be run with every implementation. Priority is only related to mfex autovalidator and not the actions autovalidator.:

$ ./configure --enable-autovalidator --enable-mfex-default-autovalidator \

The following line should be seen in the configuration log when the above options are used:

checking whether DPCLS Autovalidator is default implementation... yes
checking whether MFEX Autovalidator is default implementation... yes
checking whether actions Autovalidator is default implementation... yes

Compile OVS in debug mode to have ovs_assert statements error out if there is a mismatch in the datapath classifier lookup or packet parser implementations.

Since the AVX512 implementation of the datapath interface is disabled by default, a compile time option is available in order to test it with the OVS unit test suite:

$ ./configure --enable-dpif-default-avx512

The following line should be seen in the configuration log when the above option is used:

checking whether DPIF AVX512 is default implementation... yes


Run all the available testsuites including make check, make check-system-userspace and make check-dpdk to ensure the optimal test coverage.

Kernel datapath

Make targets are also provided for testing the Linux kernel module. Note that these tests operate by inserting modules into the running Linux kernel, so if the tests are able to trigger a bug in the OVS kernel module or in the upstream kernel then the kernel may panic.

To run the testsuite against the kernel module which is currently installed on your system, run:

$ make check-kernel

All the features documented under Unit Tests are available for the kernel datapath testsuite.


Many of the kernel tests are dependent on the utilities present in the iproute2 package, especially the ‘ip’ command. If there are many otherwise unexplained errors it may be necessary to update the iproute2 package utilities on the system. It is beyond the scope of this documentation to explain all that is necessary to build and install an updated iproute2 utilities package. The package is available from the Linux kernel organization open source git repositories.


Static Code Analysis

Static Analysis is a method of debugging Software by examining code rather than actually executing it. This can be done through ‘scan-build’ commandline utility which internally uses clang (or) gcc to compile the code and also invokes a static analyzer to do the code analysis. At the end of the build, the reports are aggregated in to a common folder and can later be analyzed using ‘scan-view’.

Open vSwitch includes a Makefile target to trigger static code analysis:

$ ./boot.sh
$ ./configure CC=clang  # clang
# or
$ ./configure CC=gcc CFLAGS="-std=gnu99"  # gcc
$ make clang-analyze

You should invoke scan-view to view analysis results. The last line of output from clang-analyze will list the command (containing results directory) that you should invoke to view the results on a browser.


The ViNePerf project, formerly known as VswitchPerf or vsperf, aims to develop a vSwitch test framework that can be used to validate the suitability of different vSwitch implementations in a telco deployment environment. More information can be found on the Anuket project wiki.

Proof of Concepts

Proof of Concepts are documentation materialized into Ansible recipes executed in VirtualBox or Libvirt environments orchestrated by Vagrant. Proof of Concepts allow developers to create small virtualized setups that demonstrate how certain Open vSwitch features are intended to work avoiding user introduced errors by overlooking instructions. Proof of Concepts are also helpful when integrating with thirdparty software, because standard unit tests with make check are limited.

Vagrant by default uses VirtualBox provider. However, if Libvirt is your choice of virtualization technology, then you can use it by installing Libvirt plugin:

$ vagrant plugin install vagrant-libvirt

And then appending --provider=libvirt flag to vagrant commands.

The host where Vagrant runs does not need to have any special software installed besides vagrant, virtualbox (or libvirt and libvirt-dev) and ansible.

The following Proof of Concepts are supported:


This particular Proof of Concept demonstrates integration with Debian and RPM packaging tools:

$ cd ./poc/builders
$ vagrant up

Once that command finished you can get packages from /var/www/html directory. Since those hosts are also configured as repositories then you can add them to /etc/apt/sources.list.d or /etc/yum.repos.d configuration files on another host to retrieve packages with yum or apt-get.

When you have made changes to OVS source code and want to rebuild packages run:

$ git commit -a
$ vagrant rsync && vagrant provision

Whenever packages are rebuilt the Open vSwitch release number increases by one and you can simply upgrade Open vSwitch by running yum or apt-get update commands.

Once you are done with experimenting you can tear down setup with:

$ vagrant destroy

Sometimes deployment of Proof of Concept may fail, if, for example, VMs don’t have network reachability to the Internet.