Explain how to register functions in the global scope

[icinga2] / INSTALL.md

# Installing Icinga 2

The recommended way of installing Icinga 2 is to use packages. The Icinga
project provides both release and development packages for a number
of operating systems.

Please check the documentation in the [doc/](doc/) directory for a current list
of available packages and detailed installation instructions.

The online documentation is available on [icinga.com/docs](https://www.icinga.com/docs/)
and will guide you step by step.

There are a number of known caveats when installing from source such as
incorrect directory and file permissions. So even if you're planning to
not use the official packages it is advisable to build your own Debian
or RPM packages.

**Disclaimer**

This information is intended for developers and packagers. It might be incomplete or unclear
in some cases. Make also sure to check our [packaging scripts on GitHub](https://github.com/Icinga/icinga-packaging)!

# Build Requirements

The following requirements need to be fulfilled in order to build the
application using a dist tarball (including notes for distributions):

* cmake >= 2.6
* GNU make (make) or ninja-build
* C++ compiler which supports C++11
  - RHEL/Fedora/SUSE: gcc-c++ >= 4.7 (extra Developer Tools on RHEL5/6 see below)
  - Debian/Ubuntu: build-essential
  - Alpine: build-base
  - you can also use clang++
* pkg-config
* OpenSSL library and header files >= 1.0.1
  - RHEL/Fedora: openssl-devel
  - SUSE: libopenssl-devel (for SLES 11: libopenssl1-devel)
  - Debian/Ubuntu: libssl-dev
  - Alpine: libressl-dev
* Boost library and header files >= 1.48.0
  - RHEL/Fedora: boost148-devel
  - Debian/Ubuntu: libboost-all-dev
  - Alpine: boost-dev
* GNU bison (bison)
* GNU flex (flex) >= 2.5.35

## Optional features

* MySQL (disable with CMake variable `ICINGA2_WITH_MYSQL` to `OFF`)
  - RHEL/Fedora: mysql-devel
  - SUSE: libmysqlclient-devel
  - Debian/Ubuntu: default-libmysqlclient-dev | libmysqlclient-dev
  - Alpine: mariadb-dev
* PostgreSQL (disable with CMake variable `ICINGA2_WITH_PGSQL` to `OFF`)
  - RHEL/Fedora: postgresql-devel
  - Debian/Ubuntu: libpq-dev
  - postgresql-dev on Alpine
* YAJL (Faster JSON library)
  - RHEL/Fedora: yajl-devel
  - Debian: libyajl-dev
  - Alpine: yajl-dev
* libedit (CLI console)
  - RHEL/Fedora: libedit-devel on CentOS (RHEL requires rhel-7-server-optional-rpms)
  - Debian/Ubuntu/Alpine: libedit-dev
* Termcap (only required if libedit doesn't already link against termcap/ncurses)
  - RHEL/Fedora: libtermcap-devel
  - Debian/Ubuntu: (not necessary)

## Special requirements

**FreeBSD**: libexecinfo (automatically used when Icinga 2 is installed via port or package)

**RHEL5** ships an ancient flex version. Updated packages are available for
example from the repoforge buildtools repository.

* x86: https://mirror.hs-esslingen.de/repoforge/redhat/el5/en/i386/buildtools/
* x86\_64: https://mirror.hs-esslingen.de/repoforge/redhat/el5/en/x86\_64/buildtools/

## Runtime user environment

By default Icinga will run as user 'icinga' and group 'icinga'. Additionally the
external command pipe and livestatus features require a dedicated command group
'icingacmd'. You can choose your own user/group names and pass them to CMake
using the `ICINGA2_USER`, `ICINGA2_GROUP` and `ICINGA2_COMMAND_GROUP` variables.
```
# groupadd icinga
# groupadd icingacmd
# useradd -c "icinga" -s /sbin/nologin -G icingacmd -g icinga icinga
```

On Alpine (which uses ash busybox) you can run:
```
# addgroup -S icinga
# addgroup -S icingacmd
# adduser -S -D -H -h /var/spool/icinga2 -s /sbin/nologin -G icinga -g icinga icinga
# adduser icinga icingacmd
```

Add the web server user to the icingacmd group in order to grant it write
permissions to the external command pipe and livestatus socket:
```
# usermod -a -G icingacmd www-data
```

Make sure to replace "www-data" with the name of the user your web server
is running as.

# Building Icinga 2

Once you have installed all the necessary build requirements you can build
Icinga 2 using the following commands:
```
$ mkdir build && cd build
$ cmake ..
$ make
$ make install
```

You can specify an alternative installation prefix using `-DCMAKE_INSTALL_PREFIX`:
```
$ cmake .. -DCMAKE_INSTALL_PREFIX=/tmp/icinga2
```

## CMake Variables

In addition to `CMAKE_INSTALL_PREFIX` here are most of the supported Icinga-specific cmake variables.

**System Environment**
- `ICINGA2_GIT_VERSION_INFO`: Whether to use Git to determine the version number; defaults to `ON`
- `ICINGA2_USER`: The user Icinga 2 should run as; defaults to `icinga`
- `ICINGA2_GROUP`: The group Icinga 2 should run as; defaults to `icinga`
- `ICINGA2_COMMAND_GROUP`: The command group Icinga 2 should use; defaults to `icingacmd`
- `ICINGA2_RUNDIR`: The location of the "run" directory; defaults to `CMAKE_INSTALL_LOCALSTATEDIR/run`
- `CMAKE_INSTALL_SYSCONFDIR`: The configuration directory; defaults to `CMAKE_INSTALL_PREFIX/etc`
- `ICINGA2_SYSCONFIGFILE`: Where to put the config file the initscript/systemd pulls it's dirs from;
  defaults to `CMAKE_INSTALL_PREFIX/etc/sysconfig/icinga2`
- `CMAKE_INSTALL_LOCALSTATEDIR`: The state directory; defaults to `CMAKE_INSTALL_PREFIX/var`
- `ICINGA2_PLUGINDIR`: The path for the Monitoring Plugins project binaries; defaults to `/usr/lib/nagios/plugins`

**Build Optimization**
- `ICINGA2_UNITY_BUILD`: Whether to perform a unity build; defaults to `ON`
- `ICINGA2_LTO_BUILD`: Whether to use link time optimization (LTO); defaults to `OFF`

**Init System**
- `USE_SYSTEMD=ON|OFF`: Use systemd or a classic SysV initscript; defaults to `OFF`
- `INSTALL_SYSTEMD_SERVICE_AND_INITSCRIPT=ON|OFF` Force install both the systemd service definition file
  and the SysV initscript in parallel, regardless of how `USE_SYSTEMD` is set.
  Only use this for special packaging purposes and if you know what you are doing.
  Defaults to `OFF`.

**Features:**
- `ICINGA2_WITH_CHECKER`: Determines whether the checker module is built; defaults to `ON`
- `ICINGA2_WITH_COMPAT`: Determines whether the compat module is built; defaults to `ON`
- `ICINGA2_WITH_DEMO`: Determines whether the demo module is built; defaults to `OFF`
- `ICINGA2_WITH_HELLO`: Determines whether the hello module is built; defaults to `OFF`
- `ICINGA2_WITH_LIVESTATUS`: Determines whether the Livestatus module is built; defaults to `ON`
- `ICINGA2_WITH_NOTIFICATION`: Determines whether the notification module is built; defaults to `ON`
- `ICINGA2_WITH_PERFDATA`: Determines whether the perfdata module is built; defaults to `ON`
- `ICINGA2_WITH_TESTS`: Determines whether the unit tests are built; defaults to `ON`

**MySQL or MariaDB:**

The following settings can be tuned for the MySQL / MariaDB IDO feature.

- `ICINGA2_WITH_MYSQL`: Determines whether the MySQL IDO module is built; defaults to `ON`
- `MYSQL_CLIENT_LIBS`: Client implementation used (mysqlclient / mariadbclient); defaults searches for `mysqlclient` and `mariadbclient`
- `MYSQL_INCLUDE_DIR`: Directory containing include files for the mysqlclient; default empty -
  checking multiple paths like `/usr/include/mysql`

See [FindMySQL.cmake](third-party/cmake/FindMySQL.cmake) for the implementation.

**PostgreSQL:**

The following settings can be tuned for the PostgreSQL IDO feature.

- `ICINGA2_WITH_PGSQL`: Determines whether the PostgreSQL IDO module is built; defaults to `ON`
- `PostgreSQL_INCLUDE_DIR`: Top-level directory containing the PostgreSQL include directories
- `PostgreSQL_LIBRARY_DIR`: Top-level directory containing the PostgreSQL libraries

See [FindMySQL.cmake](third-party/cmake/FindPostgreSQL.cmake) for the implementation.

**Version detection:**

CMake determines the Icinga 2 version number using `git describe` if the
source directory is contained in a Git repository. Otherwise the version number
is extracted from the [icinga2.spec](icinga2.spec) file. This behavior can be
overridden by creating a file called `icinga-version.h.force` in the source
directory. Alternatively the `-DICINGA2_GIT_VERSION_INFO=OFF` option for CMake
can be used to disable the usage of `git describe`.

# Building packages

> **WARNING:** Some of this information is outdated!

## Building RPMs

### Build Environment on RHEL, CentOS, Fedora, Amazon Linux

Setup your build environment:
```
yum -y install rpmdevtools
```

### Build Environment on SuSE/SLES

SLES:
```
zypper addrepo http://download.opensuse.org/repositories/devel:tools/SLE_12_SP2/devel:tools.repo
zypper refresh
zypper install rpmdevtools spectool
```

OpenSuSE:
```
zypper addrepo http://download.opensuse.org/repositories/devel:tools/openSUSE_Leap_42.3/devel:tools.repo
zypper refresh
zypper install rpmdevtools spectool
```

### Package Builds

Prepare the rpmbuild directory tree:
```
cd $HOME
rpmdev-setuptree
```

Copy the icinga2.spec file to `rpmbuild/SPEC` or fetch the latest version:
```
curl https://raw.githubusercontent.com/Icinga/icinga2/master/icinga2.spec -o $HOME/rpmbuild/SPECS/icinga2.spec
```

Copy the tarball to `rpmbuild/SOURCES` e.g. by using the `spectool` binary
provided with `rpmdevtools`:
```
cd $HOME/rpmbuild/SOURCES
spectool -g ../SPECS/icinga2.spec

cd $HOME/rpmbuild
```

Install the build dependencies. Example for CentOS 7:
```
yum -y install libedit-devel ncurses-devel gcc-c++ libstdc++-devel openssl-devel \
cmake flex bison boost-devel systemd mysql-devel postgresql-devel httpd \
selinux-policy-devel checkpolicy selinux-policy selinux-policy-doc
```

Note: If you are using Amazon Linux, systemd is not required.

A shorter way is available using the `yum-builddep` command on RHEL based systems:
```
yum-builddep SPECS/icinga2.spec
```

Build the RPM:
```
rpmbuild -ba SPECS/icinga2.spec
```

### Additional Hints

#### SELinux policy module

The following packages are required to build the SELinux policy module:

* checkpolicy
* selinux-policy (selinux-policy on CentOS 6, selinux-policy-devel on CentOS 7)
* selinux-policy-doc

#### RHEL/CentOS 5 and 6

The RedHat Developer Toolset is required for building Icinga 2 beforehand.
This contains a modern version of flex and a C++ compiler which supports
C++11 features.
```
cat >/etc/yum.repos.d/devtools-2.repo <<REPO
[testing-devtools-2-centos-\$releasever]
name=testing 2 devtools for CentOS $releasever
baseurl=https://people.centos.org/tru/devtools-2/\$releasever/\$basearch/RPMS
gpgcheck=0
REPO
```

Dependencies to devtools-2 are used in the RPM SPEC, so the correct tools
should be used for building.

As an alternative, you can use newer Boost packages provided on
[packages.icinga.com](https://packages.icinga.com/epel).
```
cat >$HOME/.rpmmacros <<MACROS
%build_icinga_org 1
MACROS
```

#### Amazon Linux

If you prefer to build packages offline, a suitable Vagrant box is located
[here](https://atlas.hashicorp.com/mvbcoding/boxes/awslinux/).

#### SLES 11

The Icinga repository provides the required boost package version and must be
added before building.

## Build Debian/Ubuntu packages

> **WARNING:** This information is outdated!

Setup your build environment on Debian/Ubuntu, copy the 'debian' directory from
the Debian packaging Git repository (https://github.com/Icinga/pkg-icinga2-debian)
into your source tree and run the following command:
```
$ dpkg-buildpackage -uc -us
```

## Build Alpine Linux packages

A simple way to setup a build environment is installing Alpine in a chroot.
In this way, you can set up an Alpine build environment in a chroot under a
different Linux distro.
There is a script that simplifies these steps with just two commands, and
can be found [here](https://github.com/alpinelinux/alpine-chroot-install).

Once the build environment is installed, you can setup the system to build
the packages by following [this document](https://wiki.alpinelinux.org/wiki/Creating_an_Alpine_package).

# Build Post Install Tasks

After building Icinga 2 yourself, your package build system should at least run the following post
install requirements:

* enable the `checker`, `notification` and `mainlog` feature by default
* run 'icinga2 api setup' in order to enable the `api` feature and generate SSL certificates for the node

## Run Icinga 2

Icinga 2 comes with a binary that takes care of loading all the relevant
components (e.g. for check execution, notifications, etc.):
```
# icinga2 daemon
[2016-12-08 16:44:24 +0100] information/cli: Icinga application loader (version: v2.5.4-231-gb10a6b7; debug)
[2016-12-08 16:44:24 +0100] information/cli: Loading configuration file(s).
[2016-12-08 16:44:25 +0100] information/ConfigItem: Committing config item(s).
...
```

### Init Script

Icinga 2 can be started as a daemon using the provided init script:
```
# /etc/init.d/icinga2
Usage: /etc/init.d/icinga2 {start|stop|restart|reload|checkconfig|status}
```

### Systemd

If your distribution uses Systemd:
```
# systemctl {start|stop|reload|status|enable|disable} icinga2
```

In case the distribution is running Systemd >227, you'll also
need to package and install the `etc/initsystem/icinga2.service.limits.conf`
file into `/etc/systemd/system/icinga2.service.d`.

### openrc

Or if your distribution uses openrc (like Alpine):
```
# rc-service icinga2
Usage: /etc/init.d/icinga2 {start|stop|restart|reload|checkconfig|status}
  ```

Note: the openrc's init.d is not shipped by default.
A working init.d with openrc can be found here: (https://git.alpinelinux.org/cgit/aports/plain/community/icinga2/icinga2.initd). If you have customized some path, edit the file and adjust it according with your setup.
Those few steps can be followed:
```
# wget https://git.alpinelinux.org/cgit/aports/plain/community/icinga2/icinga2.initd
# mv icinga2.initd /etc/init.d/icinga2
# chmod +x /etc/init.d/icinga2
```

Icinga 2 reads a single configuration file which is used to specify all
configuration settings (global settings, hosts, services, etc.). The
configuration format is explained in detail in the [doc/](doc/) directory.

By default `make install` installs example configuration files in
`/usr/local/etc/icinga2` unless you have specified a different prefix or
sysconfdir.