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This chapter provides hints on Icinga 2 debugging, development, package builds and tests.

Debug Icinga 2

This chapter targets all users who have been asked by developers to provide a stack trace or coredump if the application crashed. It is also useful for developers working with different debuggers.


This is intentionally mentioned before any development insights as debugging is a more frequent and commonly asked question.

Debug Requirements

Make sure that the debug symbols are available for Icinga 2. The Icinga 2 packages provide a debug package which must be installed separately for all involved binaries, like icinga2-bin or icinga2-ido-mysql.

Distribution Command
Debian/Ubuntu apt-get install icinga2-dbg
RHEL/CentOS yum install icinga2-debuginfo
Fedora dnf install icinga2-debuginfo icinga2-bin-debuginfo icinga2-ido-mysql-debuginfo
SLES/openSUSE zypper install icinga2-bin-debuginfo icinga2-ido-mysql-debuginfo

Furthermore, you may also have to install debug symbols for Boost and your C++ library.

If you’re building your own binaries, you should use the -DCMAKE_BUILD_TYPE=Debug cmake build flag for debug builds.

GDB as Debugger

Install GDB in your development environment.

Distribution Command
Debian/Ubuntu apt-get install gdb
RHEL/CentOS yum install gdb
Fedora dnf install gdb
SLES/openSUSE zypper install gdb


Run the icinga2 binary /usr/lib{,64}/icinga2/sbin/icinga2 with gdb, /usr/bin/icinga2 is a shell wrapper.

gdb --args /usr/lib/icinga2/sbin/icinga2 daemon

(gdb) set follow-fork-mode child

When gdb halts on SIGUSR2, press c to continue. This signal originates from the umbrella process and can safely be ignored.


Since v2.11 we would attach to the umbrella process spawned with /usr/lib/icinga2/sbin/icinga2, therefore rather attach to a running process.

# Typically the order of PIDs is: 1) umbrella 2) spawn helper 3) main process
pidof icinga2

gdb -p $(pidof icinga2 | cut -d ' ' -f3)


If gdb tells you it’s missing debug symbols, quit gdb and install them: Missing separate debuginfos, use: debuginfo-install ...

Run/restart the application.

(gdb) r

Kill the running application.

(gdb) k

Continue after breakpoint.

(gdb) c

GDB Core Dump

Either attach to the running process using gdb -p PID or start a new gdb run.

(gdb) r
(gdb) generate-core-file

GDB Backtrace

If Icinga 2 aborted its operation abnormally, generate a backtrace.


Please install the required debug symbols prior to generating a backtrace.

thread apply all is important here since this includes all running threads. We need this information when e.g. debugging dead locks and hanging features.

(gdb) bt
(gdb) thread apply all bt full

If gdb stops at a SIGPIPE signal please disable the signal before running Icinga 2. This isn’t an error, but we need to workaround it.

(gdb) handle SIGPIPE nostop noprint pass
(gdb) r

If you create a new issue, make sure to attach as much detail as possible.

GDB Backtrace from Running Process

If Icinga 2 is still running, generate a full backtrace from the running process and store it into a new file (e.g. for debugging dead locks).


Please install the required debug symbols prior to generating a backtrace.

Icinga 2 runs with 2 processes: main and command executor, therefore generate two backtrace logs and add them to the GitHub issue.

for pid in $(pidof icinga2); do gdb -p $pid -batch -ex "thread apply all bt full" -ex "detach" -ex "q" > gdb_bt_${pid}_`date +%s`.log; done

GDB Thread List from Running Process

Instead of a full backtrace, you sometimes just need a list of running threads.

for pid in $(pidof icinga2); do gdb -p $pid -batch -ex "info threads" -ex "detach" -ex "q" > gdb_threads_${pid}_`date +%s`.log; done

GDB Backtrace Stepping

Identifying the problem may require stepping into the backtrace, analysing the current scope, attributes, and possible unmet requirements. p prints the value of the selected variable or function call result.

(gdb) up
(gdb) down
(gdb) p checkable
(gdb) p checkable.px->m_Name

GDB Breakpoints

To set a breakpoint to a specific function call, or file specific line.

(gdb) b checkable.cpp:125
(gdb) b icinga::Checkable::SetEnablePerfdata

GDB will ask about loading the required symbols later, select yes instead of no.

Then run Icinga 2 until it reaches the first breakpoint. Continue with c afterwards.

(gdb) run
(gdb) c

In case you want to step into the next line of code, use n. If there is a function call where you want to step into, use s.

(gdb) n

(gdb) s

If you want to delete all breakpoints, use d and select yes.

(gdb) d


When debugging exceptions, set your breakpoint like this: b __cxa_throw.

Breakpoint Example:

(gdb) b __cxa_throw
(gdb) r
(gdb) up
(gdb) up
#11 0x00007ffff7cbf9ff in icinga::Utility::GlobRecursive(icinga::String const&, icinga::String const&, boost::function<void (icinga::String const&)> const&, int) (path=..., pattern=..., callback=..., type=1)
    at /home/michi/coding/icinga/icinga2/lib/base/utility.cpp:609
609         callback(cpath);
(gdb) l
605 #endif /* _WIN32 */
607     std::sort(files.begin(), files.end());
608     BOOST_FOREACH(const String& cpath, files) {
609         callback(cpath);
610     }
612     std::sort(dirs.begin(), dirs.end());
613     BOOST_FOREACH(const String& cpath, dirs) {
(gdb) p files
$3 = std::vector of length 11, capacity 16 = {{static NPos = 18446744073709551615, m_Data = "/etc/icinga2/conf.d/agent.conf"}, {static NPos = 18446744073709551615,
    m_Data = "/etc/icinga2/conf.d/commands.conf"}, {static NPos = 18446744073709551615, m_Data = "/etc/icinga2/conf.d/downtimes.conf"}, {static NPos = 18446744073709551615,
    m_Data = "/etc/icinga2/conf.d/groups.conf"}, {static NPos = 18446744073709551615, m_Data = "/etc/icinga2/conf.d/notifications.conf"}, {static NPos = 18446744073709551615,
    m_Data = "/etc/icinga2/conf.d/satellite.conf"}, {static NPos = 18446744073709551615, m_Data = "/etc/icinga2/conf.d/services.conf"}, {static NPos = 18446744073709551615,
    m_Data = "/etc/icinga2/conf.d/templates.conf"}, {static NPos = 18446744073709551615, m_Data = "/etc/icinga2/conf.d/test.conf"}, {static NPos = 18446744073709551615,
    m_Data = "/etc/icinga2/conf.d/timeperiods.conf"}, {static NPos = 18446744073709551615, m_Data = "/etc/icinga2/conf.d/users.conf"}}

Core Dump

When the Icinga 2 daemon crashes with a SIGSEGV signal a core dump file should be written. This will help developers to analyze and fix the problem.

Core Dump File Size Limit

This requires setting the core dump file size to unlimited.

systemctl edit icinga2.service


systemctl daemon-reload

systemctl restart icinga2
Init Script
vim /etc/init.d/icinga2
ulimit -c unlimited

service icinga2 restart

Verify that the Icinga 2 process core file size limit is set to unlimited.

for pid in $(pidof icinga2); do cat /proc/$pid/limits; done

Max core file size        unlimited            unlimited            bytes

Core Dump Kernel Format

The Icinga 2 daemon runs with the SUID bit set. Therefore you need to explicitly enable core dumps for SUID on Linux.

sysctl -w fs.suid_dumpable=2

Adjust the coredump kernel format and file location on Linux:

sysctl -w kernel.core_pattern=/var/lib/cores/core.%e.%p

install -m 1777 -d /var/lib/cores


sysctl -w kern.corefile=/cores/core.%P

chmod 777 /cores

Core Dump Analysis

Once Icinga 2 crashes again a new coredump file will be written. Please attach this file to your bug report in addition to the general details.

Simple test case for a SIGSEGV simulation with sleep:

ulimit -c unlimited
sleep 1800&
[1] <PID>
kill -SEGV <PID>
gdb `which sleep` /var/lib/cores/core.sleep.<PID>
(gdb) bt
rm /var/lib/cores/core.sleep.*

Analyzing Icinga 2:

gdb /usr/lib64/icinga2/sbin/icinga2 core.icinga2.<PID>
(gdb) bt

LLDB as Debugger

LLDB is available on macOS with the Xcode command line tools.

xcode-select --install

In order to run Icinga 2 with LLDB you need to pass the binary as argument. Since v2.11 we would attach to the umbrella process, therefore rather attach to a running process.

# Typically the order of PIDs is: 1) umbrella 2) spawn helper 3) main process
pidof icinga2

lldb -p $(pidof icinga2 | cut -d ' ' -f3)

In case you’ll need to attach to the main process immediately, you can delay the forked child process and attach to the printed PID.

$ icinga2 daemon -DInternal.DebugWorkerDelay=120
Closed FD 6 which we inherited from our parent process.
[2020-01-29 12:22:33 +0100] information/cli: Icinga application loader (version: v2.11.0-477-gfe8701d77; debug)
[2020-01-29 12:22:33 +0100] information/RunWorker: DEBUG: Current PID: 85253. Sleeping for 120 seconds to allow lldb/gdb -p <PID> attachment.
lldb -p 85253

When lldb halts on SIGUSR2, press c to continue. This signal originates from the umbrella process and can safely be ignored.


> b checkable.cpp:57
> b icinga::Checkable::ProcessCheckResult

Full backtrace:

> bt all

Select thread:

> thr sel 5

Step into:

> s

Next step:

> n


> c

Up/down in stacktrace:

> up
> down

Debug on Windows

Whenever the application crashes, the Windows error reporting (WER) can be configured to create user-mode dumps.

Tail the log file with Powershell:

Get-Content .\icinga2.log -tail 10 -wait

Debug on Windows: Dependencies

Similar to ldd or nm on Linux/Unix.

Extract the dependent DLLs from a binary with Visual Studio’s dumpbin tool in Powershell:

C:> &'C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.22.27905\bin\Hostx64\x64\dumpbin.exe' /dependents .\debug\Bin\Debug\Debug\boosttest-test-base.exe
DEBUG:    1+  >>>> &'C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.22.27905\bin\Hostx64\x64\dumpbin.exe' /dependents .\debug\Bin\Debug\Debug\boosttest-test-base.exe
Microsoft (R) COFF/PE Dumper Version 14.22.27905.0
Copyright (C) Microsoft Corporation.  All rights reserved.

Dump of file .\debug\Bin\Debug\Debug\boosttest-test-base.exe


  Image has the following dependencies:



        1000 .00cfg
       68000 .data
        B000 .idata
      148000 .pdata
      69C000 .rdata
       25000 .reloc
        1000 .rsrc
      E7A000 .text
        1000 .tls

Test Icinga 2

Snapshot Packages (Nightly Builds)

Icinga provides snapshot packages as nightly builds from Git master.

These packages contain development code which should be considered “work in progress”. While developers ensure that tests are running fine with CI actions on PRs, things might break, or changes are not yet documented in the changelog.

You can help the developers and test the snapshot packages, e.g. when larger changes or rewrites are taking place for a new major version. Your feedback is very much appreciated.

Snapshot packages are available for all supported platforms including Linux and Windows and can be obtained from

The Vagrant boxes also use the Icinga snapshot packages to allow easier integration tests. It is also possible to use Docker with base OS images and installing the snapshot packages.

If you encounter a problem, please open a new issue on GitHub and mention that you’re testing the snapshot packages.


2.11+ requires the EPEL repository for Boost 1.66+.

In addition to that, the icinga-rpm-release package already provides the icinga-snapshot-builds repository but it is disabled by default.

yum -y install
yum -y install epel-release
yum makecache

yum install --enablerepo=icinga-snapshot-builds icinga2


2.11+ requires Boost 1.66+ which either is provided by the OS, backports or Icinga stable repositories. It is advised to configure both Icinga repositories, stable and snapshot and selectively choose the repository with the -t flag on apt-get install.

apt-get update
apt-get -y install apt-transport-https wget gnupg

wget -O - | apt-key add -

DIST=$(awk -F"[)(]+" '/VERSION=/ {print $2}' /etc/os-release); \
 echo "deb icinga-${DIST} main" > \
 echo "deb-src icinga-${DIST} main" >> \

DIST=$(awk -F"[)(]+" '/VERSION=/ {print $2}' /etc/os-release); \
 echo "deb icinga-${DIST}-snapshots main" > \
 echo "deb-src icinga-${DIST}-snapshots main" >> \

apt-get update

On Debian Stretch, you’ll also need to add Debian Backports.

DIST=$(awk -F"[)(]+" '/VERSION=/ {print $2}' /etc/os-release); \
 echo "deb ${DIST}-backports main" > \

apt-get update

Then install the snapshot packages.

DIST=$(awk -F"[)(]+" '/VERSION=/ {print $2}' /etc/os-release); \
apt-get install -t icinga-${DIST}-snapshots icinga2


apt-get update
apt-get -y install apt-transport-https wget gnupg

wget -O - | apt-key add -

. /etc/os-release; if [ ! -z ${UBUNTU_CODENAME+x} ]; then DIST="${UBUNTU_CODENAME}"; else DIST="$(lsb_release -c| awk '{print $2}')"; fi; \
 echo "deb icinga-${DIST} main" > \
 echo "deb-src icinga-${DIST} main" >> \

. /etc/os-release; if [ ! -z ${UBUNTU_CODENAME+x} ]; then DIST="${UBUNTU_CODENAME}"; else DIST="$(lsb_release -c| awk '{print $2}')"; fi; \
 echo "deb icinga-${DIST}-snapshots main" > \
 echo "deb-src icinga-${DIST}-snapshots main" >> \

apt-get update

Then install the snapshot packages.

. /etc/os-release; if [ ! -z ${UBUNTU_CODENAME+x} ]; then DIST="${UBUNTU_CODENAME}"; else DIST="$(lsb_release -c| awk '{print $2}')"; fi; \
apt-get install -t icinga-${DIST}-snapshots icinga2


The required Boost packages are provided with the stable release repository.

rpm --import

zypper ar
zypper ref

zypper ar
zypper ref

Selectively install the snapshot packages using the -r parameter.

zypper in -r icinga-snapshot-builds icinga2

Unit Tests

Build the binaries and run the tests.

make -j4 -C debug
make test -C debug

Run a specific boost test:

debug/Bin/Debug/boosttest-test-base --run_test=remote_url

Develop Icinga 2

Icinga 2 can be built on many platforms such as Linux, Unix and Windows. There are limitations in terms of support, e.g. Windows is only supported for agents, not a full-featured master or satellite.

Before you start with actual development, there is a couple of pre-requisites.


Choose your Editor

Icinga 2 can be developed with your favorite editor. Icinga developers prefer these tools:

  • vim
  • CLion (macOS, Linux)
  • MS Visual Studio (Windows)
  • Atom

Editors differ on the functionality. The more helpers you get for C++ development, the faster your development workflow will be.

Get to know the architecture

Icinga 2 can run standalone or in distributed environments. It contains a whole lot more than a simple check execution engine.

Read more about it in the Technical Concepts chapter.

Get to know the code

First off, you really need to know C++ and portions of C++17 and the boost libraries. Best is to start with a book or online tutorial to get into the basics. Icinga developers gained their knowledge through studies, training and self-teaching code by trying it out and asking senior developers for guidance.

Here’s a few books we can recommend:

In addition, it is a good bet to also know SQL when diving into backend development.

Last but not least, if you are developing on Windows, get to know the internals about services and the Win32 API.

Design Patterns

Icinga 2 heavily relies on object-oriented programming and encapsulates common functionality into classes and objects. It also uses modern programming techniques to e.g. work with shared pointer memory management.

Icinga 2 consists of libraries bundled into the main binary. Therefore you’ll find many code parts in the lib/ directory wheras the actual application is built from icinga-app/. Accompanied with Icinga 2, there’s the Windows plugins which are standalone and compiled from plugins/.

Library Description
base Objects, values, types, streams, tockets, TLS, utilities, etc.
config Configuration compiler, expressions, etc.
cli CLI (sub) commands and helpers.
icinga Icinga specific objects and event handling.
remote Cluster and HTTP client/server and REST API related code.
checker Checker feature, check scheduler.
notification Notification feature, notification scheduler.
methods Command execution methods, plugins and built-in checks.
perfdata Performance data related, including Graphite, Elastic, etc.
db_ido IDO database abstraction layer.
db_ido_mysql IDO database driver for MySQL.
db_ido_pgsql IDO database driver for PgSQL.
mysql_shin Library stub for linking against the MySQL client libraries.
pgsql_shim Library stub for linking against the PgSQL client libraries.

Class Compiler

Another thing you will recognize are the .ti files which are compiled by our own class compiler into actual source code. The meta language allows developers to easily add object attributes and specify their behaviour.

Some object attributes need to be stored over restarts in the state file and therefore have the state attribute set. Others are treated as config attribute and automatically get configuration validation functions created. Hidden or read-only REST API attributes are marked with no_user_view and no_user_modify.

The most beneficial thing are getters and setters being generated. The actual object inherits from ObjectImpl<TYPE> and therefore gets them “for free”.


vim lib/perfdata/gelfwriter.ti

  [config] enable_tls;

vim lib/perfdata/gelfwriter.cpp

    if (GetEnableTls()) {

The logic is hidden in tools/mkclass/ in case you want to learn more about it. The first steps during CMake & make also tell you about code generation.

Build Tools


In its early development stages in 2012, Icinga 2 was built with autoconf/automake and separate Windows project files. We’ve found this very fragile, and have changed this into CMake as our build tool.

The most common benefits:

  • Everything is described in CMakeLists.txt in each directory
  • CMake only needs to know that a sub directory needs to be included.
  • The global CMakeLists.txt acts as main entry point for requirement checks and library/header includes.
  • Separate binary build directories, the actual source tree stays clean.
  • CMake automatically generates a Visual Studio project file icinga2.sln on Windows.

Unity Builds

Another thing you should be aware of: Unity builds on and off.

Typically, we already use caching mechanisms to reduce recompile time with ccache. For release builds, there’s always a new build needed as the difference is huge compared to a previous (major) release.

Therefore we’ve invented the Unity builds, which basically concatenates all source files into one big library source code file. The compiler then doesn’t need to load the many small files but compiles and links this huge one.

Unity builds require more memory which is why you should disable them for development builds in small sized VMs (Linux, Windows) and also Docker containers.

There’s a couple of header files which are included everywhere. If you touch/edit them, the cache is invalidated and you need to recompile a lot more files then. base/utility.hpp and remote/zone.hpp are good candidates for this.

Unit Tests

New functions and classes must implement new unit tests. Whenever you decide to add new functions, ensure that you don’t need a complex mock or runtime attributes in order to test them. Better isolate code into function interfaces which can be invoked in the Boost tests framework.

Look into the existing tests in the test/ directory and adopt new test cases.

Specific tests require special time windows, they are only enabled in debug builds for developers. This is the case e.g. for testing the flapping algorithm with expected state change detection at a specific point from now.

Style Guide

Overview of project files:

File Type File Name/Extension Description
Header .hpp Classes, enums, typedefs inside the icinga Namespace.
Source .cpp Method implementation for class functions, static/global variables.
CMake CMakeLists.txt Build configuration, source and header file references.
CMake Source .cmake Source/Header files generated from CMake placeholders.
ITL/conf.d .conf Template library and example files as configuration
Class Compiler .ti Object classes in our own language, generates source code as <filename>-ti.{c,h}pp.
Lexer/Parser .ll, .yy Flex/Bison code generated into source code from CMake builds.
Docs .md Markdown docs and READMEs.

Anything else are additional tools and scripts for developers and build systems.

All files must include the copyright header. We don’t use the current year as this implies yearly updates we don’t want.

Depending on the file type, this must be a comment.

/* Icinga 2 | (c) 2012 Icinga GmbH | GPLv2+ */
# Icinga 2 | (c) 2012 Icinga GmbH | GPLv2+

Code Formatting

Tabs instead of spaces. Inside Visual Studio, choose to keep tabs instead of spaces. Tabs should use 4 spaces indent by default, depending on your likings.

We follow the clang format, with some exceptions.

  • Curly braces for functions and classes always start at a new line.
String ConfigObjectUtility::EscapeName(const String& name)

String ConfigObjectUtility::CreateObjectConfig(const Type::Ptr& type, const String& fullName,
    bool ignoreOnError, const Array::Ptr& templates, const Dictionary::Ptr& attrs)
  • Too long lines break at a parameter, the new line needs a tab indent.
    static String CreateObjectConfig(const Type::Ptr& type, const String& fullName,
        bool ignoreOnError, const Array::Ptr& templates, const Dictionary::Ptr& attrs);
  • Conditions require curly braces if it is not a single if with just one line.
    if (s == "OK") {
    } else {

    if (!n)
  • There’s a space between if and the opening brace (. Also after the closing brace ) and opening curly brace {.
  • Negation with ! doesn’t need an extra space.
  • Else branches always start in the same line after the closing curly brace.

Code Comments

Add comments wherever you think that another developer will have a hard time to understand the complex algorithm. Or you might have forgotten it in a year and struggle again. Also use comments to highlight specific stages in a function. Generally speaking, make things easier for the team and external contributors.

Comments can also be used to mark additional references and TODOs. If there is a specific GitHub issue or discussion going on, use that information as a summary and link over to it on purpose.

  • Single line comments may use // or /* ... */
  • Multi line comments must use this format:
/* Ensure to check for XY
 * This relies on the fact that ABC has been set before.

Function Docs

Function header documentation must be added. The current code basis needs rework, future functions must provide this.

Editors like CLion or Visual Studio allow you to type /** followed by Enter and generate the skeleton from the implemented function.

Add a short summary in the first line about the function’s purpose. Edit the param section with short description on their intention. The return value should describe the value type and additional details.


 * Reads a message from the connected peer.
 * @param stream ASIO TLS Stream
 * @param yc Yield Context for ASIO
 * @param maxMessageLength maximum size of bytes read.
 * @return A JSON string
String JsonRpc::ReadMessage(const std::shared_ptr<AsioTlsStream>& stream, boost::asio::yield_context yc, ssize_t maxMessageLength)

While we can generate code docs from it, the main idea behind it is to provide on-point docs to fully understand all parameters and the function’s purpose in the same spot.

Only include other headers which are mandatory for the header definitions. If the source file requires additional headers, add them there to avoid include loops.

The included header order is important.

  • First, include the library header i2-<libraryname>.hpp, e.g. i2-base.hpp.
  • Second, include all headers from Icinga itself, e.g. remote/apilistener.hpp. base before icinga before remote, etc.
  • Third, include third-party and external library headers, e.g. openssl and boost.
  • Fourth, include STL headers.


The included header order is important.

  • First, include the header whose methods are implemented.
  • Second, include all headers from Icinga itself, e.g. remote/apilistener.hpp. base before icinga before remote, etc.
  • Third, include third-party and external library headers, e.g. openssl and boost.
  • Fourth, include STL headers.

Always use an empty line after the header include parts.


The icinga namespace is used globally, as otherwise we would need to write icinga::Utility::FormatDateTime().

using namespace icinga;

Other namespaces must be declared in the scope they are used. Typically this is inside the function where boost::asio and variants would complicate the code.

    namespace ssl = boost::asio::ssl;

    auto context (std::make_shared<ssl::context>(ssl::context::sslv23));


Ensure to pass values and pointers as const reference. By default, all values will be copied into the function scope, and we want to avoid this wherever possible.

std::vector<EventQueue::Ptr> EventQueue::GetQueuesForType(const String& type)

C++ only allows to return a single value. This can be abstracted with returning a specific class object, or with using a map/set. Array and Dictionary objects increase the memory footprint, use them only where needed.

A common use case for Icinga value types is where a function can return different values - an object, an array, a boolean, etc. This happens in the inner parts of the config compiler expressions, or config validation.

The function caller is responsible to determine the correct value type and handle possible errors.

Specific algorithms may require to populate a list, which can be passed by reference to the function. The inner function can then append values. Do not use a global shared resource here, unless this is locked by the caller.

Conditions and Cases

Prefer if-else-if-else branches. When integers are involved, switch-case statements increase readability. Don’t forget about break though!

Avoid using ternary operators where possible. Putting a condition after an assignment complicates reading the source. The compiler optimizes this anyways.


    int res = s == "OK" ? 0 : s == "WARNING" ? 1;

    return res;


    int res = 3;

    if (s == "OK") {
        res = 0;
    } else if (s == "WARNING") {
        res = 1;

Even better: Create a lookup map instead of if branches. The complexity is reduced to O(log(n)).

    std::map<String, unsigned int> stateMap = {
        { "OK", 1 },
        { "WARNING", 2 }

    auto it = stateMap.find(s);

    if (it == stateMap.end()) {
        return 3

    return it.second;

The code is not as short as with a ternary operator, but one can re-use this design pattern for other generic definitions with e.g. moving the lookup into a utility class.

Once a unit test is written, everything works as expected in the future.

Locks and Guards

Lock access to resources where multiple threads can read and write. Icinga objects can be locked with the ObjectLock class.

Object locks and guards must be limited to the scope where they are needed. Otherwise we could create dead locks.

        ObjectLock olock(frame.Locals);
        for (const Dictionary::Pair& kv : frame.Locals) {
            AddSuggestion(matches, word, kv.first);

Objects and Pointers

Use shared pointers for objects. Icinga objects implement the Ptr typedef returning an intrusive_ptr for the class object (object.hpp). This also ensures reference counting for the object’s lifetime.

Use raw pointers with care!

Some methods and classes require specific shared pointers, especially when interacting with the Boost library.

Value Types

Icinga has its own value types. These provide methods to allow generic serialization into JSON for example, and other type methods which are made available in the DSL too.

  • Always use String instead of std::string. If you need a C-string, use the CStr() method.
  • Avoid casts and rather use the Convert class methods.
    double s = static_cast<double>(v); //Wrong

    double s = Convert::ToDouble(v);   //Correct, ToDouble also provides overloads with different value types
  • Prefer STL containers for internal non-user interfaces. Icinga value types add a small overhead which may decrease performance if e.g. the function is called 100k times.
  • Array::FromVector and variants implement conversions, use them.


Don’t re-invent the wheel. The Utility class provides many helper functions which allow you e.g. to format unix timestamps, search in filesystem paths.

Also inspect the Icinga objects, they also provide helper functions for formatting, splitting strings, joining arrays into strings, etc.


2.11 depends on Boost 1.66. Use the existing libraries and header-only includes for this specific version.

Note: Prefer C++17 features where possible, e.g. std::atomic and lambda functions.


Events and Runtime:

Network I/O:

Consider abstracting their usage into *utility.{c,h}pp files with wrapping existing Icinga types. That also allows later changes without rewriting large code parts.


A new Boost library should be explained in a PR and discussed with the team.

This requires package dependency changes.

If you consider an external library or code to be included with Icinga, the following requirements must be fulfilled:

  • License is compatible with GPLv2+. Boost license, MIT works, Apache is not.
  • C++17 is supported
  • Header only implementations are preferred, external libraries require packages on every distribution.
  • No additional frameworks, Boost is the only allowed.
  • The code is proven to be robust and the GitHub repository is alive, or has 1k+ stars. Good libraries also provide a user list, if e.g. Ceph is using it, this is a good candidate.


Icinga allows the user to configure logging backends, e.g. syslog or file.

Any log message inside the code must use the Log() function.

  • The first parameter is the severity level, use them with care.
  • The second parameter defines the location/scope where the log happened. Typically we use the class name here, to better analyse the logs the user provide in GitHub issues and on the community channels.
  • The third parameter takes a log message string

If the message string needs to be computed from existing values, everything must be converted to the String type beforehand. This conversion for every value is very expensive which is why we try to avoid it.

Instead, use Log() with the shift operator where everything is written on the stream and conversions are explicitly done with templates in the background.

The trick here is that the Log object is destroyed immediately after being constructed once. The destructor actually evaluates the values and sends it to registers loggers.

Since flushing the stream every time a log entry occurs is very expensive, a timer takes care of flushing the stream every second.


If logging stopped, the flush timer thread may be dead. Inspect that with gdb/lldb.

Avoid log messages which could irritate the user. During implementation, developers can change log levels to better see what’s going one, but remember to change this back to debug or remove it entirely.


Avoid using goto statements. There are rare occasions where they are allowed:

  • The code would become overly complicated within nested loops and conditions.
  • Event processing and C interfaces.
  • Question/Answer loops within interactive CLI commands.

Typedef and Auto Keywords

Typedefs allow developers to use shorter names for specific types, classes and structs.

    typedef std::map<String, std::shared_ptr<NamespaceValue> >::iterator Iterator;

These typedefs should be part of the Class definition in the header, or may be defined in the source scope where they are needed.

Avoid declaring global typedefs, unless necessary.

Using the auto keyword allows to ignore a specific value type. This comes in handy with maps/sets where no specific access is required.

The following example iterates over a map returned from GetTypes().

    for (const auto& kv : GetTypes()) {

The long example would require us to define a map iterator, and a slightly different algorithm.

    typedef std::map<String, DbType::Ptr> TypeMap;
    typedef std::map<String, DbType::Ptr>::const_iterator TypeMapIterator;

    TypeMap types = GetTypes();

    for (TypeMapIterator it = types.begin(); it != types.end(); it++) {

We could also use a pair here, but requiring to know the specific types of the map keys and values.

    typedef std::pair<String, DbType::Ptr> kv_pair;

    for (const kv_pair& kv : GetTypes()) {

After all, auto shortens the code and one does not always need to know about the specific types. Function documentation for GetTypes() is required though.

Whitespace Cleanup

Patches must be cleaned up and follow the indent style (tabs instead of spaces). You should also remove any trailing whitespaces.

git diff allows to highlight such.

vim $HOME/.gitconfig

[color "diff"]
        whitespace = red reverse

vim also can match these and visually alert you to remove them.

vim $HOME/.vimrc

highlight ExtraWhitespace ctermbg=red guibg=red
match ExtraWhitespace /\s\+$/
autocmd BufWinEnter * match ExtraWhitespace /\s\+$/
autocmd InsertEnter * match ExtraWhitespace /\s\+\%#\@<!$/
autocmd InsertLeave * match ExtraWhitespace /\s\+$/
autocmd BufWinLeave * call clearmatches()

Development Environment

Linux Dev Environment

Based on CentOS 7, we have an early draft available inside the Icinga Vagrant boxes: centos7-dev.

If you’re compiling Icinga 2 natively without any virtualization layer in between, this usually is faster. This is also the reason why developers on macOS prefer native builds over Linux or Windows VMs. Don’t forget to test the actual code on Linux later! Socket specific stuff like epoll is not available on Unix kernels.

Depending on your workstation and environment, you may either develop and run locally, use a container deployment pipeline or put everything in a high end resource remote VM.

Fork into your own repository, e.g.

Create two build directories for different binary builds.

  • debug contains the debug build binaries. They contain more debug information and run tremendously slower than release builds from packages. Don’t use them for benchmarks.
  • release contains the release build binaries, as you would install them on a live system. This helps comparing specific scenarios for race conditions and more.
mkdir -p release debug

Proceed with the specific distribution examples below. Keep in mind that these instructions are best effort and sometimes out-of-date. Git Master may contain updates.

CentOS 7

yum -y install gdb vim git bash-completion htop centos-release-scl

yum -y install rpmdevtools ccache \
 cmake make devtoolset-11-gcc-c++ flex bison \
 openssl-devel boost169-devel systemd-devel \
 mysql-devel postgresql-devel libedit-devel \

groupadd icinga
groupadd icingacmd
useradd -c "icinga" -s /sbin/nologin -G icingacmd -g icinga icinga

ln -s /bin/ccache /usr/local/bin/gcc
ln -s /bin/ccache /usr/local/bin/g++

git clone && cd icinga2

The debug build binaries contain specific code which runs slower but allows for better debugging insights.

For benchmarks, change CMAKE_BUILD_TYPE to RelWithDebInfo and build inside the release directory.

First, off export some generics for Boost.

export I2_BOOST="-DBoost_NO_BOOST_CMAKE=TRUE -DBoost_NO_SYSTEM_PATHS=TRUE -DBOOST_LIBRARYDIR=/usr/lib64/boost169 -DBOOST_INCLUDEDIR=/usr/include/boost169 -DBoost_ADDITIONAL_VERSIONS='1.69;1.69.0'"

Second, add the prefix path to it.

export I2_GENERIC="$I2_BOOST -DCMAKE_INSTALL_PREFIX=/usr/local/icinga2"

Third, define the two build types with their specific CMake variables.


Fourth, depending on your likings, you may add a bash alias for building, or invoke the commands inside:

alias i2_debug="cd /root/icinga2; mkdir -p debug; cd debug; scl enable devtoolset-11 -- cmake $I2_DEBUG ..; make -j2; sudo make -j2 install; cd .."
alias i2_release="cd /root/icinga2; mkdir -p release; cd release; scl enable devtoolset-11 -- cmake $I2_RELEASE ..; make -j2; sudo make -j2 install; cd .."

This is taken from the centos7-dev Vagrant box.

The source installation doesn’t set proper permissions, this is handled in the package builds which are officially supported.

chown -R icinga:icinga /usr/local/icinga2/var/

/usr/local/icinga2/lib/icinga2/prepare-dirs /usr/local/icinga2/etc/sysconfig/icinga2
/usr/local/icinga2/sbin/icinga2 api setup
vim /usr/local/icinga2/etc/icinga2/conf.d/api-users.conf

/usr/local/icinga2/lib/icinga2/sbin/icinga2 daemon

Debian 10

Debian Buster doesn’t need updated Boost packages from, the distribution already provides 1.66+. For older versions such as Stretch, include the release repository for as shown in the setup instructions.

docker run -ti debian:buster bash

apt-get update
apt-get -y install apt-transport-https wget gnupg

apt-get -y install gdb vim git cmake make ccache build-essential libssl-dev bison flex default-libmysqlclient-dev libpq-dev libedit-dev monitoring-plugins
apt-get -y install libboost-all-dev
ln -s /usr/bin/ccache /usr/local/bin/gcc
ln -s /usr/bin/ccache /usr/local/bin/g++

groupadd icinga
groupadd icingacmd
useradd -c "icinga" -s /sbin/nologin -G icingacmd -g icinga icinga

git clone && cd icinga2

mkdir debug release

export I2_DEB="-DBoost_NO_BOOST_CMAKE=TRUE -DBoost_NO_SYSTEM_PATHS=TRUE -DBOOST_LIBRARYDIR=/usr/lib/x86_64-linux-gnu -DBOOST_INCLUDEDIR=/usr/include -DCMAKE_INSTALL_RPATH=/usr/lib/x86_64-linux-gnu"
export I2_GENERIC="-DCMAKE_INSTALL_PREFIX=/usr/local/icinga2 -DICINGA2_PLUGINDIR=/usr/local/sbin"

cd debug
cmake .. $I2_DEBUG
cd ..

make -j2 install -C debug

The source installation doesn’t set proper permissions, this is handled in the package builds which are officially supported.

chown -R icinga:icinga /usr/local/icinga2/var/

/usr/local/icinga2/lib/icinga2/prepare-dirs /usr/local/icinga2/etc/sysconfig/icinga2
/usr/local/icinga2/sbin/icinga2 api setup
vim /usr/local/icinga2/etc/icinga2/conf.d/api-users.conf

/usr/local/icinga2/lib/icinga2/sbin/icinga2 daemon

Ubuntu 18 Bionic

Requires Boost packages from

docker run -ti ubuntu:bionic bash

apt-get update
apt-get -y install apt-transport-https wget gnupg

wget -O - | apt-key add -

. /etc/os-release; if [ ! -z ${UBUNTU_CODENAME+x} ]; then DIST="${UBUNTU_CODENAME}"; else DIST="$(lsb_release -c| awk '{print $2}')"; fi; \
 echo "deb icinga-${DIST} main" > \
 echo "deb-src icinga-${DIST} main" >> \

apt-get update
apt-get -y install gdb vim git cmake make ccache build-essential libssl-dev bison flex default-libmysqlclient-dev libpq-dev libedit-dev monitoring-plugins

apt-get install -y libboost1.67-icinga-all-dev

ln -s /usr/bin/ccache /usr/local/bin/gcc
ln -s /usr/bin/ccache /usr/local/bin/g++

groupadd icinga
groupadd icingacmd
useradd -c "icinga" -s /sbin/nologin -G icingacmd -g icinga icinga

git clone && cd icinga2

mkdir debug release

export I2_DEB="-DBoost_NO_BOOST_CMAKE=TRUE -DBoost_NO_SYSTEM_PATHS=TRUE -DBOOST_LIBRARYDIR=/usr/lib/x86_64-linux-gnu/icinga-boost -DBOOST_INCLUDEDIR=/usr/include/icinga-boost -DCMAKE_INSTALL_RPATH=/usr/lib/x86_64-linux-gnu/icinga-boost"
export I2_GENERIC="-DCMAKE_INSTALL_PREFIX=/usr/local/icinga2 -DICINGA2_PLUGINDIR=/usr/local/sbin"

cd debug
cmake .. $I2_DEBUG
cd ..
make -j2 install -C debug

The source installation doesn’t set proper permissions, this is handled in the package builds which are officially supported.

chown -R icinga:icinga /usr/local/icinga2/var/

/usr/local/icinga2/lib/icinga2/prepare-dirs /usr/local/icinga2/etc/sysconfig/icinga2
/usr/local/icinga2/sbin/icinga2 api setup
vim /usr/local/icinga2/etc/icinga2/conf.d/api-users.conf

/usr/local/icinga2/lib/icinga2/sbin/icinga2 daemon

macOS Dev Environment

It is advised to use Homebrew to install required build dependencies. Macports have been reported to work as well, typically you’ll get more help with Homebrew from Icinga developers.

The idea is to run Icinga with the current user, avoiding root permissions. This requires at least v2.11.


This is a pure development setup for Icinga developers reducing the compile time in contrast to VMs. There are no packages, startup scripts or dependency management involved.

macOS agents are not officially supported.

macOS uses its own TLS implementation, Icinga relies on extra OpenSSL packages requiring updates apart from vendor security updates.


Explicitly use OpenSSL 1.1.x, older versions are out of support.

brew install ccache boost cmake bison flex openssl@1.1 mysql-connector-c++ postgresql libpq
sudo mkdir /opt/ccache

sudo ln -s `which ccache` /opt/ccache/clang
sudo ln -s `which ccache` /opt/ccache/clang++

vim $HOME/.bash_profile

# ccache is managed with symlinks to avoid collision with cgo
export PATH="/opt/ccache:$PATH"

source $HOME/.bash_profile


Icinga is built as release (optimized build for packages) and debug (more symbols and details for debugging). Debug builds typically run slower than release builds and must not be used for performance benchmarks.

The preferred installation prefix is /usr/local/icinga/icinga2. This allows to put e.g. Icinga Web 2 into the /usr/local/icinga directory as well.

mkdir -p release debug

export I2_USER=$(id -u -n)
export I2_GROUP=$(id -g -n)
export I2_GENERIC="-DCMAKE_INSTALL_PREFIX=/usr/local/icinga/icinga2 -DICINGA2_USER=$I2_USER -DICINGA2_GROUP=$I2_GROUP -DOPENSSL_INCLUDE_DIR=/usr/local/opt/openssl@1.1/include -DOPENSSL_SSL_LIBRARY=/usr/local/opt/openssl@1.1/lib/libssl.dylib -DOPENSSL_CRYPTO_LIBRARY=/usr/local/opt/openssl@1.1/lib/libcrypto.dylib -DICINGA2_PLUGINDIR=/usr/local/sbin -DICINGA2_WITH_PGSQL=OFF -DCMAKE_EXPORT_COMPILE_COMMANDS=ON"

cd debug
cmake $I2_DEBUG ..
cd ..

make -j4 -C debug
make -j4 install -C debug

In order to run Icinga without any path prefix, and also use Bash completion it is advised to source additional things into the local dev environment.

export PATH=/usr/local/icinga/icinga2/sbin/:$PATH

test -f /usr/local/icinga/icinga2/etc/bash_completion.d/icinga2 && source /usr/local/icinga/icinga2/etc/bash_completion.d/icinga2
Build Aliases

This is derived from dnsmichi’s flavour and not generally best practice.

vim $HOME/.bash_profile

export I2_USER=$(id -u -n)
export I2_GROUP=$(id -g -n)
export I2_GENERIC="-DCMAKE_INSTALL_PREFIX=/usr/local/icinga/icinga2 -DICINGA2_USER=$I2_USER -DICINGA2_GROUP=$I2_GROUP -DOPENSSL_INCLUDE_DIR=/usr/local/opt/openssl@1.1/include -DOPENSSL_SSL_LIBRARY=/usr/local/opt/openssl@1.1/lib/libssl.dylib -DOPENSSL_CRYPTO_LIBRARY=/usr/local/opt/openssl@1.1/lib/libcrypto.dylib -DICINGA2_PLUGINDIR=/usr/local/sbin -DICINGA2_WITH_PGSQL=OFF -DCMAKE_EXPORT_COMPILE_COMMANDS=ON"


alias i2_debug="mkdir -p debug; cd debug; cmake $I2_DEBUG ..; make -j4; make -j4 install; cd .."
alias i2_release="mkdir -p release; cd release; cmake $I2_RELEASE ..; make -j4; make -j4 install; cd .."

export PATH=/usr/local/icinga/icinga2/sbin/:$PATH
test -f /usr/local/icinga/icinga2/etc/bash_completion.d/icinga2 && source /usr/local/icinga/icinga2/etc/bash_completion.d/icinga2

source $HOME/.bash_profile


make install doesn’t set all required permissions, override this.

chown -R $I2_USER:$I2_GROUP /usr/local/icinga/icinga2


Start Icinga in foreground.

icinga2 daemon

Reloads triggered with HUP or cluster syncs just put the process into background.


brew install monitoring-plugins

sudo vim /usr/local/icinga/icinga2/etc/icinga2/constants.conf
const PluginDir = "/usr/local/sbin"

Backends: Redis

brew install redis
brew services start redis

Databases: MariaDB

brew install mariadb
mkdir -p /usr/local/etc/my.cnf.d
brew services start mariadb

vim $HOME/.my.cnf

user = root
password = supersecurerootpassword

sudo -i
ln -s /Users/michi/.my.cnf $HOME/.my.cnf
mysql -e 'create database icinga;'
mysql -e "grant all on icinga.* to 'icinga'@'localhost' identified by 'icinga';"
mysql icinga < $HOME/dev/icinga/icinga2/lib/db_ido_mysql/schema/mysql.sql


icinga2 api setup
cd /usr/local/icinga/icinga2/var/lib/icinga2/certs
icinga2 pki new-cert --cn ${HOST_NAME} --csr ${HOST_NAME}.csr --key ${HOST_NAME}.key
icinga2 pki sign-csr --csr ${HOST_NAME}.csr --cert ${HOST_NAME}.crt
echo "const NodeName = \"${HOST_NAME}\"" >> /usr/local/icinga/icinga2/etc/icinga2/constants.conf


While it is recommended to use Docker or the Icinga Web 2 development VM pointing to the shared IDO database resource/REST API, you can also install it locally on macOS.

The required steps are described in this script.

Windows Dev Environment

The following sections explain how to setup the required build tools and how to run and debug the code.


If you’re going to setup a dev environment on a fresh Windows machine and don’t care for the details,

  1. ensure there are 35 GB free space on C:
  2. run the following in an administrative Powershell:
  3. Enable-WindowsOptionalFeature -FeatureName "NetFx3" -Online (reboot when asked!)
  4. powershell -NoProfile -ExecutionPolicy Bypass -Command "Invoke-Expression (New-Object Net.WebClient).DownloadString('')" (will take some time)

This installs everything needed for cloning and building Icinga 2 on the command line (Powershell) as follows:

(Don’t forget to open a new Powershell window to be able to use the newly installed Git.)

git clone
cd .\icinga2\
mkdir build
cd .\build\

& "C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\Common7\IDE\CommonExtensions\Microsoft\CMake\CMake\bin\cmake.exe" `
  -DICINGA2_UNITY_BUILD=OFF -DBoost_INCLUDE_DIR=C:\local\boost_1_84_0-Win64 `
  -DBISON_EXECUTABLE=C:\ProgramData\chocolatey\lib\winflexbison3\tools\win_bison.exe `
  -DFLEX_EXECUTABLE=C:\ProgramData\chocolatey\lib\winflexbison3\tools\win_flex.exe ..

& "C:\Program Files (x86)\Microsoft Visual Studio\2019\BuildTools\MSBuild\Current\Bin\MSBuild.exe" .\icinga2.sln

Building icinga2.sln via Visual Studio itself seems to require a reboot after installing the build tools.


Open an administrative command prompt (Win key, type “cmd”, right-click and “run as administrator”) and paste the following instructions:

@powershell -NoProfile -ExecutionPolicy Bypass -Command "iex ((new-object net.webclient).DownloadString(''))" && SET PATH=%PATH%;%ALLUSERSPROFILE%\chocolatey\bin

Git, Posh and Vim

In case you are used to vim, start a new administrative Powershell:

choco install -y vim

The same applies for Git integration in Powershell:

choco install -y poshgit

Powershell Posh Git

In order to fix the colors for commands like git status or git diff, edit $HOME/.gitconfig in your Powershell and add the following lines:

vim $HOME/.gitconfig

[color "status"]
    changed = cyan bold
    untracked = yellow bold
    added = green bold
    branch = cyan bold
    unmerged = red bold

[color "diff"]
    frag = cyan
    new = green bold
    commit = yellow
    old = red white

[color "branch"]
  current = yellow reverse
  local = yellow
  remote = green bold
  remote = red bold

Visual Studio

Thanks to Microsoft they’ll now provide their Professional Edition of Visual Studio as community version, free for use for open source projects such as Icinga. The installation requires ~9GB disk space. Download the web installer and start the installation.

Note: Only Visual Studio 2019 is covered here. Older versions are not supported.

You need a free Microsoft account to download and also store your preferences.

Install the following complete workloads:

  • C++ Desktop Development
  • .NET Desktop Development

In addition also choose these individual components on Visual Studio:

  • .NET
    • .NET Framework 4.x targeting packs
    • .NET Framework 4.x.y SDKs
  • Code tools
    • Git for Windows
    • GitHub Extension for Visual Studio
    • NuGet package manager
  • Compilers, build tools and runtimes
    • C# and Visual Basic Roslyn compilers
    • C++ 2019 Redistributable Update
    • C++ CMake tools for Windows
    • C++/CLI Support for v142 build tools (14.22)
    • MSBuild
    • MSVC v142 - VS 2019 C++ x64/x86 build tools (v14.22)
  • Debugging and testing
    • .NET profiling tools
    • C++ profiling tools
    • Just-in-Time debugger
  • Development activities
    • C# and Visual Basic
    • C++ core features
    • IntelliCode
    • Live Share
  • Games and Graphics
    • Graphics debugger and GPU profiler for DirectX (required by C++ profiling tools)
  • SDKs, libraries and frameworks
    • Windows 10 SDK (10.0.18362.0 or later)
    • Windows Universal C Runtime

Visual Studio Installer Visual Studio Installer Visual Studio Installer

After a while, Visual Studio will be ready.

Style Guide for Visual Studio

Navigate into Tools > Options > Text Editor and repeat the following for

  • C++
  • C#

Navigate into Tabs and set:

  • Indenting: Smart (default)
  • Tab size: 4
  • Indent size: 4
  • Keep tabs (instead of spaces)

Visual Studio Tabs

Flex and Bison

Install it using chocolatey:

choco install -y winflexbison

Chocolatey installs these tools into the hidden directory C:\ProgramData\chocolatey\lib\winflexbison\tools.


Icinga 2 requires the OpenSSL library. Download the Win64 package and install it into c:\local\OpenSSL-Win64.

Once asked for Copy OpenSSLs DLLs to select The Windows system directory. That way CMake/Visual Studio will automatically detect them for builds and packaging.


We cannot use the chocolatey package as this one does not provide any development headers.

Choose 1.1.1 LTS from manual downloads for best compatibility.


Icinga needs the development header and library files from the Boost library.

Visual Studio translates into the following compiler versions:

  • msvc-14.2 = Visual Studio 2019
Pre-built Binaries

Prefer the pre-built package over self-compiling, if the newest version already exists.

Download the boost-binaries for

  • msvc-14.2 is Visual Studio 2019
  • 64 for 64 bit builds

Run the installer and leave the default installation path in C:\local\boost_1_84_0.

Source & Compile

In order to use the boost development header and library files you need to download Boost and then extract it to e.g. C:\local\boost_1_84_0.


Just use C:\local, the zip file already contains the sub folder. Extraction takes a while, the archive contains more than 70k files.

In order to integrate Boost into Visual Studio, open the Developer Command Prompt from the start menu, and navigate to C:\local\boost_1_84_0.

Execute bootstrap.bat first.

cd C:\local\boost_1_84_0

Once finished, specify the required toolset to compile boost against Visual Studio. This takes quite some time in a Windows VM. Boost Context uses Assembler code, which isn’t treated as exception safe by the VS compiler. Therefore set the additional compilation flag according to this entry.

b2 --toolset=msvc-14.2 link=static threading=multi runtime-link=static address-model=64 asmflags=\safeseh

Windows Boost Build in VS Development Console


TortoiseGit provides a graphical integration into the Windows explorer. This makes it easier to checkout, commit and whatnot.

Download TortoiseGit on your system.

In order to clone via Git SSH you also need to create a new directory called .ssh inside your user’s home directory. Therefore open a command prompt (win key, type cmd, enter) and run mkdir .ssh. Add your id_rsa private key and public key files into that directory.

Start the setup routine and choose OpenSSH as default secure transport when asked.

Open a Windows Explorer window and navigate into

cd %HOMEPATH%\source\repos

Right click and select Git Clone from the context menu.

Use ssh:// for SSH clones, otherwise.


CMake uses CPack and NSIS to create the setup executable including all binaries and libraries in addition to setup dialogues and configuration. Therefore we’ll need to install NSIS first.

We also need to install the Windows Installer XML (WIX) toolset. This has .NET 3.5 as a dependency which might need a reboot of the system which is not handled properly by Chocolatey. Therefore install it first and reboot when asked.

Enable-WindowsOptionalFeature -FeatureName "NetFx3" -Online
choco install -y wixtoolset


Icinga 2 uses CMake to manage the build environment. You can generate the Visual Studio project files using CMake. Download and install CMake. Select to add it to PATH for all users when asked.


In order to properly detect the Boost libraries and VS 2019, install CMake 3.15.2+.



Once setup is completed, open a command prompt and navigate to

cd %HOMEPATH%\source\repos

Build Icinga with specific CMake variables. This generates a new Visual Studio project file called icinga2.sln.

Visual Studio translates into the following:

  • msvc-14.2 = Visual Studio 2019

You need to specify the previously installed component paths.

Variable Value Description
BOOST_ROOT C:\local\boost_1_84_0 Root path where you’ve extracted and compiled Boost.
BOOST_LIBRARYDIR Binary: C:\local\boost_1_84_0\lib64-msvc-14.2, Source: C:\local\boost_1_84_0\stage Path to the static compiled Boost libraries, directory must contain lib.
BISON_EXECUTABLE C:\ProgramData\chocolatey\lib\winflexbison\tools\win_bison.exe Path to the Bison executable.
FLEX_EXECUTABLE C:\ProgramData\chocolatey\lib\winflexbison\tools\win_flex.exe Path to the Flex executable.
ICINGA2_UNITY_BUILD OFF Disable unity builds for development environments.

Tip: If you have previously opened a terminal, run refreshenv to re-read updated PATH variables.

Build Scripts

Icinga provides the build scripts inside the Git repository.

Open a new Powershell and navigate into the cloned Git repository. Set specific environment variables and run the build scripts.

cd %HOMEPATH%\source\repos\icinga2


The debug MSI package is located in the debug directory.

If you did not follow the above steps with Boost binaries and OpenSSL paths, you can still modify the environment variables.

$env:CMAKE_GENERATOR='Visual Studio 16 2019'

$env:ICINGA2_INSTALLPATH = 'C:\Program Files\Icinga2-debug'

Icinga 2 in Visual Studio

This requires running the configure script once.

Navigate to

cd %HOMEPATH%\source\repos\icinga2\debug

Open icinga2.sln. Log into Visual Studio when asked.

On the right panel, select to build the Bin/icinga-app solution.

The executable binaries are located in Bin\Release\Debug in your icinga2 project directory.

Navigate there and run icinga2.exe --version.

cd %HOMEPATH%\source\repos\icinga2\Bin\Release\Debug
icinga2.exe --version

Release Package

This is part of the build process script. Override the build type and pick a different build directory.

cd %HOMEPATH%\source\repos\icinga2



The release MSI package is located in the release directory.

Embedded Dev Env: Pi


This isn’t officially supported yet, just a few hints how you can do it yourself.

The following examples source from armhf on Raspberry Pi.


apt install -y ccache


echo 'export PATH="/usr/lib/ccache:$PATH"' | tee -a ~/.bashrc

source ~/.bashrc && echo $PATH


Copy the icinga2 source code into $HOME/icinga2. Clone the deb-icinga2 repository into debian/.

git clone $HOME/icinga2
git clone $HOME/icinga2/debian

Then build a Debian package and install it like normal.

dpkg-buildpackage -uc -us

Package Builds

This documentation is explicitly meant for packagers and the Icinga build infrastructure.

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

  • cmake >= 2.6
  • GNU make (make) or ninja-build
  • C++ compiler which supports C++17
    • RHEL/Fedora/SUSE: gcc-c++ >= 7 (extra Developer Tools on RHEL7 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
    • Debian/Ubuntu: libssl-dev
    • Alpine: libressl-dev
  • Boost library and header files >= 1.66.0
    • RHEL/Fedora: boost166-devel
    • Debian/Ubuntu: libboost-all-dev
    • Alpine: boost-dev
  • GNU bison (bison)
  • GNU flex (flex) >= 2.5.35
  • systemd headers
    • Only required when using systemd
    • Debian/Ubuntu: libsystemd-dev
    • RHEL/Fedora: systemd-devel

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
  • 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)

RHEL6: Requires a newer boost version which is available on with a version suffixed name.

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: Example

Once you have installed all the necessary build requirements you can build Icinga 2 using the following commands:

mkdir release && cd release
cmake ..
cd ..
make -C release
make install -C release

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.

For all variables regarding defaults paths on in CMake, see GNUInstallDirs.

Also see CMakeLists.txt for details.

System Environment

  • CMAKE_INSTALL_SYSCONFDIR: The configuration directory; defaults to CMAKE_INSTALL_PREFIX/etc
  • CMAKE_INSTALL_LOCALSTATEDIR: The state directory; defaults to CMAKE_INSTALL_PREFIX/var
  • ICINGA2_CONFIGDIR: Main config directory; defaults to CMAKE_INSTALL_SYSCONFDIR/icinga2 usually /etc/icinga2
  • ICINGA2_CACHEDIR: Directory for cache files; defaults to CMAKE_INSTALL_LOCALSTATEDIR/cache/icinga2 usually /var/cache/icinga2
  • ICINGA2_DATADIR: Data directory for the daemon; defaults to CMAKE_INSTALL_LOCALSTATEDIR/lib/icinga2 usually /var/lib/icinga2
  • ICINGA2_LOGDIR: Logfiles of the daemon; defaults to CMAKE_INSTALL_LOCALSTATEDIR/log/icinga2 usually/var/log/icinga2`
  • ICINGA2_SPOOLDIR: Spooling directory ; defaults to CMAKE_INSTALL_LOCALSTATEDIR/spool/icinga2 usually /var/spool/icinga2
  • ICINGA2_INITRUNDIR: Runtime data for the init system; defaults to CMAKE_INSTALL_LOCALSTATEDIR/run/icinga2 usually /run/icinga2
  • 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_SYSCONFIGFILE: Where to put the config file the initscript/systemd pulls it’s dirs from;
  • defaults to CMAKE_INSTALL_PREFIX/etc/sysconfig/icinga2
  • 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. Note: This requires additional memory and is not advised for building VMs, Docker for Mac and embedded hardware.
  • 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.


  • 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_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 for implementation details.


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: File path to PostgreSQL library : (or[ver] file)

See FindPostgreSQL.cmake for implementation details.

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_VERSION 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 RPMs

Build Environment on RHEL, CentOS, Fedora, Amazon Linux

Setup your build environment:

yum -y install rpmdevtools

Build Environment on SuSE/SLES


zypper addrepo
zypper refresh
zypper install rpmdevtools spectool


zypper addrepo
zypper refresh
zypper install rpmdevtools spectool

Package Builds

Prepare the rpmbuild directory tree:

cd $HOME

Snapshot builds:

curl -o $HOME/rpmbuild/SPECS/icinga2.spec


The above command builds snapshot packages. Change to the release branch for release package builds.

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

The RedHat Developer Toolset is required for building Icinga 2 beforehand. This contains a C++ compiler which supports C++17 features.

yum install centos-release-scl

Dependencies to devtools-11 are used in the RPM SPEC, so the correct tools should be used for building.

Amazon Linux

If you prefer to build packages offline, a suitable Vagrant box is located here.

Build Debian/Ubuntu packages

Setup your build environment on Debian/Ubuntu, copy the ‘debian’ directory from the Debian packaging Git repository ( 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.

Once the build environment is installed, you can setup the system to build the packages by following this document.

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 TLS 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:

Usage: /etc/init.d/icinga2 {start|stop|restart|reload|checkconfig|status}


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.


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: ( If you have customized some path, edit the file and adjust it according with your setup. Those few steps can be followed:

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/ directory.

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

Windows Builds

The Windows MSI packages are located at

The build infrastructure is based on GitLab CI and an Ansible provisioned Windows VM running in OpenStack.

The runner uses the scripts located in tools/win32 to configure, build and test the packages. Uploading them to the package repository is a separate step. For manual package creation, please refer to this chapter.

Windows build pipeline in GitLab

Continuous Integration

Icinga uses the integrated CI capabilities on GitHub in the development workflow. This ensures that incoming pull requests and branches are built on create/push events. Contributors and developers can immediately see whether builds fail or succeed and help the final reviews.

  • For Linux, we are currently using Travis CI.
  • For Windows, AppVeyor has been integrated.

Future plans involve making use of GitHub Actions.

In addition to our development platform on GitHub, we are using GitLab’s CI platform to build binary packages for all supported operating systems and distributions. These CI pipelines provide even more detailed insights into specific platform failures and developers can react faster.

CI: Travis CI

Travis CI provides Ubuntu as base distribution where Icinga is compiled from sources followed by running the unit tests and a config validation check.

For details, please refer to the .travis.yml configuration file.

CI: AppVeyor

AppVeyor provides Windows as platform where Visual Studio and Boost libraries come pre-installed.

Icinga is built using the Powershell scripts located in tools/win32. In addition to that, the unit tests are run.

Please check the appveyor.yml configuration file for details.

Advanced Development Tips

GDB Pretty Printers

Install the boost, python and icinga2 pretty printers. Absolute paths are required, so please make sure to update the installation paths accordingly (pwd).

mkdir -p ~/.gdb_printers && cd ~/.gdb_printers

Boost Pretty Printers compatible with Python 3:

$ git clone && cd Boost-Pretty-Printer
$ git checkout python-3
$ pwd

Python Pretty Printers:

cd ~/.gdb_printers
svn co svn://

Icinga 2 Pretty Printers:

mkdir -p ~/.gdb_printers/icinga2 && cd ~/.gdb_printers/icinga2

Now you’ll need to modify/setup your ~/.gdbinit configuration file. You can download the one from Icinga 2 and modify all paths.

Example on Fedora 22:

$ wget -O ~/.gdbinit
$ vim ~/.gdbinit

set print pretty on

import sys
sys.path.insert(0, '/home/michi/.gdb_printers/icinga2')
from icingadbg import register_icinga_printers

import sys
sys.path.insert(0, '/home/michi/.gdb_printers/python')
from libstdcxx.v6.printers import register_libstdcxx_printers

import sys
sys.path.insert(0, '/home/michi/.gdb_printers/Boost-Pretty-Printer')
import boost_print

If you are getting the following error when running gdb, the libstdcxx printers are already preloaded in your environment and you can remove the duplicate import in your ~/.gdbinit file.

RuntimeError: pretty-printer already registered: libstdc++-v6