general.rst

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, refer to one of the other installation guides listed in :doc:`index`.

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.
  • MSVC 2013. Refer to :doc:`windows` for additional Windows build instructions.

  While OVS may be compatible with other compilers, optimal support for atomic operations may be missing, making OVS very slow (see lib/ovs-atomic.h).

• 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.

• libcap-ng, written by Steve Grubb, is optional but recommended. It is required to run OVS daemons as a non-root user with dropped root privileges. If libcap-ng is installed, then Open vSwitch will automatically build with support for it.

• Python 2.7. You must also have the Python six library.

On Linux, you may choose to compile the kernel module that comes with the Open vSwitch distribution or to use the kernel module built into the Linux kernel (version 3.3 or later). See the :doc:`/faq/index` question "What features are not available in the Open vSwitch kernel datapath that ships as part of the upstream Linux kernel?" for more information on this trade-off. You may also use the userspace-only implementation, at some cost in features and performance. Refer to :doc:`userspace` for details.

To compile the kernel module on Linux, you must also install the following:

• A supported Linux kernel version.

  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 NET_CLS_POLICE is obsolete and not needed.)

  On kernels before 3.11, the ip_gre module, for GRE tunnels over IP (NET_IPGRE), must not be loaded or compiled in.

  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 2.63 or later.
• Automake version 1.10 or later.
• libtool version 2.4 or later. (Older versions might work too.)

To run the unit tests, you also need:

• Perl. Version 5.10.1 is known to work. Earlier versions should also work.

The datapath tests for userspace and Linux datapaths also rely upon:

• pyftpdlib. Version 1.2.0 is known to work. Earlier versions should also work.
• GNU wget. Version 1.16 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.

If you are going to extensively modify Open vSwitch, 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

• flake8, version 2.X, along with the hacking flake8 plugin (for Python code). The automatic flake8 check that runs against Python code has some warnings enabled that come from the "hacking" flake8 plugin. If it's not installed, the warnings just won't occur until it's run on a system with "hacking" installed. Note that there are problems with flake8 3.0 and the "hacking" plugin. To ensure you get flake8 2.X, you can use:

  $ pip install 'flake8<3.0'
  

You may find the ovs-dev script found in utilities/ovs-dev.py useful.

Installation Requirements

The machine you build Open vSwitch on may not be the one you run it on. To simply install and run Open vSwitch you require 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).
• Python 2.7. You must also have the Python six library.

On Linux you should ensure that /dev/urandom exists. To support TAP devices, you must also ensure that /dev/net/tun exists.

Bootstrapping

This step is not needed if you have downloaded a released tarball. If you pulled the sources directly from an Open vSwitch Git tree or got a Git tree snapshot, then run boot.sh in the top source directory to build the "configure" script:

$ ./boot.sh

Configuring

Configure the package by running the configure script. You can usually invoke configure without any arguments. For example:

$ ./configure

By default all files are installed under /usr/local. Open vSwitch also expects to find its database in /usr/local/etc/openvswitch by default. If you want to install all files into, e.g., /usr and /var instead of /usr/local and /usr/local/var and expect to use /etc/openvswitch as the default database directory, add options as shown here:

$ ./configure --prefix=/usr --localstatedir=/var --sysconfdir=/etc

Note

Open vSwitch installed with packages like .rpm (e.g. via yum install or rpm -ivh) and .deb (e.g. via apt-get install or dpkg -i) use the above configure options.

By default, static libraries are built and linked against. If you want to use shared libraries instead:

$ ./configure --enable-shared

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 supply special flags to the C compiler, specify them as CFLAGS on the configure command line. If you want the default CFLAGS, which include -g to build debug symbols and -O2 to enable optimizations, you must include them yourself. For example, to build with the default CFLAGS plus -mssse3, you might run configure as follows:

$ ./configure CFLAGS="-g -O2 -mssse3"

For efficient hash computation special flags can be passed to leverage built-in intrinsics. For example on X86_64 with SSE4.2 instruction set support, CRC32 intrinsics can be used by passing -msse4.2:

$ ./configure CFLAGS="-g -O2 -msse4.2"`

If you are on a different processor and don't know what flags to choose, it is recommended to use -march=native settings:

$ ./configure CFLAGS="-g -O2 -march=native"

With this, GCC will detect the processor and automatically set appropriate flags for it. This should not be used if you are compiling OVS outside the target machine.

Note

CFLAGS are not applied when building the Linux kernel module. Custom CFLAGS for the kernel module are supplied using the EXTRA_CFLAGS variable when running make. For example:

$ make EXTRA_CFLAGS="-Wno-error=date-time"

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

Note

If --with-linux requests building for an unsupported version of Linux, then configure will fail with an error message. Refer to the :doc:`/faq/index` for advice in that case.

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

If you plan to do much Open vSwitch development, you might want to add --enable-Werror, which adds the -Werror option to the compiler command line, turning warnings into errors. That makes it impossible to miss warnings generated by the build. For example:

$ ./configure --enable-Werror

To build with gcov code coverage support, add --enable-coverage:

$ ./configure --enable-coverage

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

$ ./configure --help

You can also run configure from a separate build directory. This is helpful if you want to build Open vSwitch in more than one way from a single source directory, e.g. to try out both GCC and Clang builds, or to build kernel modules for more than one Linux version. For example:

$ mkdir _gcc && (cd _gcc && ./configure CC=gcc)
$ mkdir _clang && (cd _clang && ./configure CC=clang)

Under certains loads the ovsdb-server and other components perform better when using the jemalloc memory allocator, instead of the glibc memory allocator. If you wish to link with jemalloc add it to LIBS:

$ ./configure LIBS=-ljemalloc

Building

1. Run GNU make in the build directory, e.g.:

   $ make
   

   or if GNU make is installed as "gmake":

   $ gmake
   

   If you used a separate build directory, run make or gmake from that directory, e.g.:

   $ make -C _gcc
   $ make -C _clang
   

   For improved warnings if you installed sparse (see "Prerequisites"), add C=1 to the command line.

   Note

   Some versions of Clang and ccache are not completely compatible. If you see unusual warnings when you use both together, consider disabling ccache.

2. Consider running the testsuite. Refer to Testing for instructions.

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

   $ make install
   

5. If you built kernel modules, you may install them, e.g.:

   $ make modules_install
   

   It is possible that you already had a Open vSwitch kernel module installed on your machine that came from upstream Linux (in a different directory). To make sure that you load the Open vSwitch kernel module you built from this repository, you should create a depmod.d file that prefers your newly installed kernel modules over the kernel modules from upstream Linux. The following snippet of code achieves the same:

   $ config_file="/etc/depmod.d/openvswitch.conf"
   $ for module in datapath/linux/*.ko; do
     modname="$(basename ${module})"
     echo "override ${modname%.ko} * extra" >> "$config_file"
     echo "override ${modname%.ko} * weak-updates" >> "$config_file"
     done
   $ depmod -a
   

   Finally, load the kernel modules that you need. e.g.:

   $ /sbin/modprobe openvswitch
   

   To verify that the modules have been loaded, run /sbin/lsmod and check that openvswitch is listed:

   $ /sbin/lsmod | grep openvswitch
   

   Note

   If the modprobe operation fails, look at the last few kernel log messages (e.g. with dmesg | tail). Generally, issues like this occur when Open vSwitch is 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, include the output from the dmesg and modinfo commands mentioned above.

Starting

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. Before ovsdb-server itself can be started, configure a database that it can use:

$ mkdir -p /usr/local/etc/openvswitch
$ ovsdb-tool create /usr/local/etc/openvswitch/conf.db \
    vswitchd/vswitch.ovsschema

Configure ovsdb-server to use database created 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:

$ mkdir -p /usr/local/var/run/openvswitch
$ 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 --log-file

Note

If you built Open vSwitch without SSL support, then omit --private-key, --certificate, and --bootstrap-ca-cert.)

Initialize the database using ovs-vsctl. This is only necessary the first time after you create the database with ovsdb-tool, though running it at any time is harmless:

$ ovs-vsctl --no-wait init

Start the main Open vSwitch daemon, telling it to connect to the same Unix domain socket:

$ ovs-vswitchd --pidfile --detach --log-file

Validating

At this point you can 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

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 by using the same configure options as was used for installing the previous version. If you do not use the same configure options, you can end up with two different versions of Open vSwitch executables installed in different locations.

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 Starting 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.

Testing

This section describe Open vSwitch's built-in support for various test suites. You must bootstrap, configure and build Open vSwitch (steps are in "Building and Installing Open vSwitch for Linux, FreeBSD or NetBSD" above) before you run the tests described here. 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 report test failures as bugs and include the testsuite.log in your report.

Note

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

Coverage

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-lcoc target:

$ make check-lcov

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

$ make check-lcov TESTSUITEFLAGS=-j8 -k ovn

Valgrind

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.*.

All the same options are available via TESTSUITEFLAGS.

Hint

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

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, first read and follow the instructions under Testing above. Second, 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.

Note

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

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

Note

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.

Vagrant

Important

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

Note

You must Bootstrap and Configure the sources 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 \
    configure_ovs,test_ovs_kmod,test_ovs_system_userspace

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

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

Native

The datapath testsuite as invoked by Vagrant above may also be run manually on a Linux system with root privileges. 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-traffic.dir.

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

To install the kernel module from the current build directory and run the testsuite against that kernel module:

$ make check-kmod

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

Continuous Integration with Travis-CI

A .travis.yml file is provided to automatically build Open vSwitch with various build configurations and run the testsuite using travis-ci. Builds will be performed with gcc, sparse and clang with the -Werror compiler flag included, therefore the build will fail if a new warning has been introduced.

The CI build is triggered via git push (regardless of the specific branch) or pull request against any Open vSwitch GitHub repository that is linked to travis-ci.

Instructions to setup travis-ci for your GitHub repository:

1. Go to http://travis-ci.org/ and sign in using your GitHub ID.

2. Go to the "Repositories" tab and enable the ovs repository. You may disable builds for pushes or pull requests.

3. In order to avoid forks sending build failures to the upstream mailing list, the notification email recipient is encrypted. If you want to receive email notification for build failures, replace the the encrypted string:

   1. Install the travis-ci CLI (Requires ruby >=2.0): gem install travis

   2. In your Open vSwitch repository: travis encrypt [email protected]

   3. Add/replace the notifications section in .travis.yml and fill in the secure string as returned by travis encrypt:

      notifications:
        email:
          recipients:
            - secure: "....."
      

Note

You may remove/omit the notifications section to fall back to default notification behaviour which is to send an email directly to the author and committer of the failing commit. Note that the email is only sent if the author/committer have commit rights for the particular GitHub repository.

4. Pushing a commit to the repository which breaks the build or the testsuite will now trigger a email sent to [email protected]

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.

Reporting Bugs

Report problems to [email protected].