2   Installation

2.1   Ubuntu Linux

This section describes how to build Clixon from source on Ubuntu Linux. You can use this as a base for other platforms as well since many steps (such as prereqs) are similar.

Further, the vagrant scripts show how to build for some other Linux variants, such as Centos.

2.1.1   Prerequisites

General prerequisites

Install packages:

sudo apt-get install flex bison

Install and build CLIgen:

git clone https://github.com/clicon/cligen.git
cd cligen;
configure
make;
sudo make install

Add a clixon user and group, using useradd and usermod:

sudo useradd -M -U clixon
sudo usermod -a -G clixon <youruser>  # Remember to re-log in for this to take effect
sudo usermod -a -G clixon www-data # Only if RESTCONF

If you do not require RESTCONF, then continue with Build clixon from source.

RESTCONF HTTP Support

The RESTCONF implementation supports two HTTP configurations:

1. Clixon native HTTP server
2. FastCGI for reverse proxy

Clixon native HTTP server

Native http server requires openssl 1.1 or later.

Install TLS:

sudo apt-get install libssl-dev

Thereafter configure using default options:

configure

FastCGI for reverse proxy

FastCGI requires support for Nginx or similar reverse HTTP proxy:

sudo apt-get install nginx libfcgi-dev

Then, when building clixon from source (see below), configure clixon with:

configure --with-restconf=fcgi

Note that the libfcgi-dev package might not exist in Ubuntu 18 bionic or later, in which case need to build fcgi from source.

Note also that the ‘fcgi’ installation package might have a different name on other Linux distributions, such as “fcgi-dev” (alpine), “fcgi” (arch), “fcgi-devkit” (freebsd).

2.1.2   Build Clixon from source

Download clixon source code:

git clone https://github.com/clicon/clixon.git

Configure Clixon using one of the following RESTCONF configurations:

configure --with-restconf=native # clixon native HTTP server
configure --with-restconf=fcgi   # FastCGI support for reverse proxy, the default
                                 # when no '--with-restconf' option is specified
configure --without-restconf     # Do not build restconf

For more configure options see: Configure options.

Build and install:

make                      # Compile
sudo make install         # Install libs, binaries, config-files and include-files
sudo ldconfig             # To link new dynamic libraries

Building the example and utils

To build and install the example app, from the top level clixon directory:

make example
cd example
sudo make install

To build the utils for running the tests, from the top level clixon directory:

sudo apt install libcurl4-openssl-dev
cd util
make
sudo make install

See also the Quickstart section section for building a complete hello world example.

2.2   FreeBSD

FreeBSD has ports for both cligen and clixon available. You can install them as binary packages, or you can build them in a ports source tree locally.

If you install using binary packages or build from the ports collection, the installation locations comply with FreeBSD standards and you have some assurance that the installed package is correct and functional.

The Nginx setup for RESTCONF is altered - the system user www is used, and the restconf daemon is placed in /usr/local/sbin.

2.2.1   Binary package install

To install the pre-built binary package, use the FreeBSD pkg command:

% pkg install clixon

This will install clixon and all the dependencies needed.

2.2.2   Build from source on FreeBSD

If you prefer you can also build clixon from the FreeBSD ports collection

Once you have the Ports Collection installed, you build clixon like this

% cd /usr/ports/devel/clixon
% make && make install

One issue with using the Ports Collection is that it may not install the latest version from GitHub. The port is generally updated soon after an official release, but there is still a lag between it and the master branch. The maintainer for the port tries to assure that the master branch will compile always, but no FreeBSD specific functional testing is done.

2.3   Systemd

Once installed, Clixon can be setup using systemd. The following shows an example with the backend and restconf daemons from the main example. Install them as /etc/systemd/system/example.service and /etc/systemd/system/example_restconf.service, for example.

2.3.1   Systemd backend

The backend service is installed at /etc/systemd/system/example.service, for example. Note that in this example, the backend installation requires the restconf service, which is not necessary.

[Unit]
Description=Starts and stops a clixon example service on this system
Wants=example_restconf.service
[Service]
Type=forking
User=root
RestartSec=60
Restart=on-failure
ExecStart=/usr/local/sbin/clixon_backend -s running -f /usr/local/etc/example.xml
[Install]
WantedBy=multi-user.target

2.3.2   Systemd restconf

The Restconf service can be installed at, for example, /etc/systemd/system/example_restconf.service:

[Unit]
Description=Starts and stops an example clixon restconf service on this system
Wants=example.service
After=example.service
[Service]
Type=simple
User=root
Restart=on-failure
ExecStart=/usr/local/sbin/clixon_restconf -f /usr/local/etc/example.xml
[Install]
WantedBy=multi-user.target

The restconf daemon can also be started internally using the clixon-lib process-control RPC. For more info, see Restconf section.

2.4   Docker

Clixon can run in a docker container. As an example the docker directory has boilerplate code for building Clixon in a container:

cd docker/base
make docker

For complete examples see:

• Hello world
• Clixon CI test container
• Openconfig

2.5   Vagrant

Clixon uses vagrant in testing. For example to start a Freebsd vagrant host, install Clixon and run the test suite, do

cd test/vagrant
./vagrant.sh generic/freebsd12

Other platforms include: ubuntu/bionic64 and generic/centos8. To look at how Clixon is installed natively on those platforms please look in the build scripts under test/vagrant/.

2.6   OpenWRT

See Clixon cross-compiler for Openwrt

2.7   Prereqs from source

2.7.1   FCGI

For RESTCONF using fcgi build fcgi from source as follows:

git clone https://github.com/FastCGI-Archives/fcgi2
cd fcgi2
./autogen.sh
./configure --prefix=/usr
make
sudo make install

2.8   SSH subsystem

You can expose clixon_netconf as an SSH subsystem according to RFC 6242. Register the subsystem in /etc/sshd_config:

Subsystem netconf /usr/local/bin/clixon_netconf

and then invoke it from a client using:

ssh -s <host> netconf

2.9   Configure options

The Clixon configure script (generated by autoconf) includes several options apart from the standard ones.

These include (standard options are omitted)

--enable-debug	Build with debug symbols, default: no
--enable-yang-patch
	Enable RFC 8072 YANG patch (plain patch is always enabled)
--enable-publish
	Enable publish of notification streams using SSE and curl
--disable-http1
	Disable native http/1.1 (ie http/2 only)
--disable-nghttp2
	Disable native http/2 using libnghttp2 (ie http/1 only)
--with-cligen=dir
	Use CLIGEN here
--with-restconf=native
	RESTCONF using native http. (DEFAULT)
--with-restconf=fcgi
	RESTCONF using fcgi/ reverse proxy.
--without-restconf
	No RESTCONF
--with-configfile=FILE
	Set default path to config file
--with-libxml2	Use gnome/libxml2 regex engine
--without-sigaction
	Disable sigaction logic (some platforms do not support SA_RESTART mode)
--with-yang-installdir=DIR
	Install Clixon yang files here (default: ${prefix}/share/clixon)
--with-yang-standard-dir=DIR
	Location of standard IETF/IEEE YANG specs for tests and example (default: $prefix/share/yang/standard)

There are also some variables that can be set, such as:

./configure LINKAGE=static                     # Build static libraries
./configure CFLAGS="-O1 -Wall" INSTALLFLAGS="" # Use other CFLAGS

Note, you need to reconfigure and recompile from scratch if you want to build static libs

2.10   macOS

Clixon can be built on macOS, however not all tests will pass at this moment and there might be pieces which will not run properly.

A few packages must be installed using for example HomeBrew:

brew install openssl nghttp2

Since we install a few libraries from HomeBrew we might want to set C and library paths:

$ export LIBRARY_PATH=$LIBRARY_PATH:/opt/homebrew/opt/openssl/lib
$ export C_INCLUDE_PATH=/opt/homebrew/opt/openssl/include/

Then Cligen and Clixon can be built as normal. Since Clixon will install things in “/usr/local/sbin/” you might want to add this to PATH. Either temporarily using:

export PATH=$PATH:/usr/local/sbin/

Or permanently by adding the above to .bash_profile or similar.

Since macOS don’t use systemd or similar you’ll have to start and stop clixon_backend etc manually.