icinga2/doc/4.1-configuration-syntax.md

Configuration Syntax

Object Definition

Icinga 2 features an object-based configuration format. In order to define objects the object keyword is used:

object Host "host1.example.org" {
  display_name = "host1",

  macros = {
    address = "192.168.0.1"
  }
}

Note

The Icinga 2 configuration format is agnostic to whitespaces and new-lines.

Note

Colons (:) are not permitted in object names.

Each object is uniquely identified by its type (Host) and name (host1.example.org). Objects can contain a comma-separated list of property declarations. The following data types are available for property values:

Numeric Literals

A floating-point number.

Example:

-27.3

Duration Literals

Similar to floating-point numbers except for the fact that they support suffixes to help with specifying time durations.

Example:

2.5m

Supported suffixes include ms (milliseconds), s (seconds), m (minutes), h (hours) and d (days).

String Literals

A string.

Example:

"Hello World!"

Certain characters need to be escaped. The following escape sequences are supported:

Character	Escape sequence
"	\"
\	\\
<TAB>	\t
<CARRIAGE-RETURN>	\r
<LINE-FEED>	\n
<BEL>	\b
<FORM-FEED>	\f

In addition to these pre-defined escape sequences you can specify arbitrary ASCII characters using the backslash character (\) followed by an ASCII character in octal encoding.

Multiline String Literals

Strings spanning multiple lines can be specified by enclosing them in {{{ and }}}.

Example.

{{{This
is
a multi-line
string.}}}

Note

Unlike in ordinary strings special characters to not have to be escaped in multi-line string literals.

Boolean Literals

The keywords true and false are equivalent to 1 and 0 respectively.

Null Value

The null keyword can be used to specify an empty value.

Dictionary

An unordered list of key-value pairs. Keys must be unique and are compared in a case-insensitive manner.

Individual key-value pairs must be separated from each other with a comma. The comma after the last key-value pair is optional.

Example:

{
  address = "192.168.0.1",
  port = 443
}

Note

Identifiers may not contain certain characters (e.g. space) or start with certain characters (e.g. digits). If you want to use a dictionary key that is not a valid identifier you can put the key in double quotes.

Note

Setting a dictionary key to null causes the key and its value to be removed from the dictionary.

Array

An ordered list of values.

Individual array elements must be separated from each other with a comma. The comma after the last element is optional.

Example:

[ "hello", 42 ]

Note

An array may simultaneously contain values of different types, such as strings and numbers.

Operators

In addition to the = operator shown above a number of other operators to manipulate configuration objects are supported. Here's a list of all available operators:

Operator =

Sets a dictionary element to the specified value.

Example:

{
  a = 5,
  a = 7
}

In this example a has the value 7 after both instructions are executed.

Operator +=

Modifies a dictionary or array by adding new elements to it.

Example:

{
  a = [ "hello" ],
  a += [ "world" ]
}

In this example a contains both "hello" and "world". This currently only works for dictionaries and arrays.

Indexer

The indexer syntax provides a convenient way to set dictionary elements.

Example:

{
  hello["key"] = "world"
}

This is equivalent to writing:

{
  hello += {
    key = "world"
  }
}

Inheritance

Objects can inherit attributes from other objects.

Example:

template Host "default-host" {
  check_interval = 30,

  macros["color"] = "red"
}

template Host "test-host" inherits "default-host" {
  macros["color"] = "blue"
}

object Host "localhost" inherits "test-host" {
  macros["address"] = "127.0.0.1",
  macros["address6"] = "::1"
}

The default-host and test-host objects are marked as templates using the template keyword. Unlike ordinary objects templates are not instantiated at runtime. Parent objects do not necessarily have to be templates though in general they are.

Note

The final macros dictionary contains all 3 macros and the macro color has the value "blue".

Parent objects are resolved in the order they're specified using the inherits keyword.

Variables

Global variables can be set using the set keyword:

set VarName = "some value"

The value can be a string, number, array or a dictionary.

Constant Expressions

Simple calculations can be performed using the constant expression syntax:

{
  check_interval = (15 * 60)
}

Valid operators include +, -, * and /. The default precedence rules can be overriden by grouping expressions using parentheses:

{
  check_interval ((15 * 60) / 2)
}

Global variables may be used in constant expressions.

set MyCheckInterval = 10m

...

{
  check_interval = (MyCheckInterval / 2.5)
}

Note

Constant expressions are evaluated as soon as they're encountered in the configuration file.

Comments

The Icinga 2 configuration format supports C/C++-style comments.

Example:

/*
 This is a comment.
 */
object Host "localhost" {
  check_interval = 30, // this is also a comment.
  retry_interval = 15
}

Includes

Other configuration files can be included using the include directive. Paths must be relative to the configuration file that contains the include directive.

Example:

include "some/other/file.conf"
include "conf.d/*.conf"

Note

Wildcard includes are not recursive.

Icinga also supports include search paths similar to how they work in a C/C++ compiler:

include <itl/itl.conf>

Note the use of angle brackets instead of double quotes. This causes the config compiler to search the include search paths for the specified file. By default $PREFIX/icinga2 is included in the list of search paths. Additional include search paths can be added using command-line options.

Wildcards are not permitted when using angle brackets.

Library directive

The library directive can be used to manually load additional libraries. Libraries can be used to provide additional object types and methods.

Example:

library "snmphelper"

Note

The icinga library is automatically loaded at startup. You don't need to load it manually.