icinga2/doc/3.03-custom-attributes-runt...

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Custom Attributes

Using Custom Attributes at Runtime

Custom attributes may be used in command definitions to dynamically change how the command is executed.

Additionally there are Icinga 2 features such as the PerfDataWriter type which use custom attributes to format their output.

Tip

Custom attributes are identified by the 'vars' dictionary attribute as short name. Accessing the different attribute keys is possible using the '.' accessor.

Custom attributes in command definitions or performance data templates are evaluated at runtime when executing a command. These custom attributes cannot be used elsewhere (e.g. in other configuration attributes).

Here is an example of a command definition which uses user-defined custom attributes:

object CheckCommand "my-ping" {
  import "plugin-check-command"

  command = [
    PluginDir + "/check_ping",
    "-4",
    "-H", "$address$",
    "-w", "$wrta$,$wpl$%",
    "-c", "$crta$,$cpl$%",
    "-p", "$packets$",
    "-t", "$timeout$"
  ]

  vars.wrta = 100
  vars.wpl = 5
  vars.crta = 200
  vars.cpl = 15
  vars.packets = 5
  vars.timeout = 0
}

Custom attribute names used at runtime must be enclosed in two $ signs, e.g. $address$. When using the $ sign as single character, you need to escape it with an additional dollar sign ($$).

Runtime Custom Attributes Evaluation Order

When executing commands Icinga 2 checks the following objects in this order to look up custom attributes and their respective values:

  1. User object (only for notifications)
  2. Service object
  3. Host object
  4. Command object
  5. Global custom attributes in the IcingaVars constant

This execution order allows you to define default values for custom attributes in your command objects. The my-ping command shown above uses this to set default values for some of the latency thresholds and timeouts.

When using the my-ping command you can override all or some of the custom attributes in the service definition like this:

object Service "ping" {
  host_name = "localhost"
  check_command = "my-ping"

  vars.packets = 10 // Overrides the default value of 5 given in the command
}

If a custom attribute isn't defined anywhere an empty value is used and a warning is emitted to the Icinga 2 log.

Best Practice

By convention every host should have an address custom attribute. Hosts which have an IPv6 address should also have an address6 custom attribute. This may also be mandatory requirement for using user interfaces and addons.

Runtime Custom Attributes as Environment Variables

TODO

The env command object attribute specifies a list of environment variables with values calculated from either runtime macros or custom attributes which should be exported as environment variables prior to executing the command.

This is useful for example for hiding sensitive information on the command line output when passing credentials to database checks:

object CheckCommand "mysql-health" {
  import "plugin-check-command",

  command = PluginDir + "/check_mysql -H $address$ -d $db$",
  /* default custom attribute values */
  vars = {
    mysql_user = "icinga_check",
    mysql_pass = "password"
  },

  env = {
    MYSQLUSER = "$mysql_user$",
    MYSQLPASS = "$mysql_pass$"
  }
}

Runtime Macros

Next to custom attributes there are additional runtime macros made available by Icinga 2. These runtime macros reflect the current object state and may change over time while custom attributes are configured statically (but can be modified at runtime using external commands).

Host Runtime Macros

The following host custom attributes are available in all commands that are executed for hosts or services:

Name Description
host.name The name of the host object.
host.displayname The value of the display_name attribute.
host.state The host's current state. Can be one of UNREACHABLE, UP and DOWN.
host.stateid The host's current state. Can be one of 0 (up), 1 (down) and 2 (unreachable).
host.statetype The host's current state type. Can be one of SOFT and HARD.
host.attempt The current check attempt number.
host.maxattempt The maximum number of checks which are executed before changing to a hard state.
host.laststate The host's previous state. Can be one of UNREACHABLE, UP and DOWN.
host.laststateid The host's previous state. Can be one of 0 (up), 1 (down) and 2 (unreachable).
host.laststatetype The host's previous state type. Can be one of SOFT and HARD.
host.laststatechange The last state change's timestamp.
host.durationsec The time since the last state change.
host.latency The host's check latency.
host.executiontime The host's check execution time.
host.output The last check's output.
host.perfdata The last check's performance data.
host.lastcheck The timestamp when the last check was executed.
host.totalservices Number of services associated with the host.
host.totalservicesok Number of services associated with the host which are in an OK state.
host.totalserviceswarning Number of services associated with the host which are in a WARNING state.
host.totalservicesunknown Number of services associated with the host which are in an UNKNOWN state.
host.totalservicescritical Number of services associated with the host which are in a CRITICAL state.

Service Runtime Macros

The following service macros are available in all commands that are executed for services:

Name Description
service.description The short name of the service object.
service.displayname The value of the display_name attribute.
service.checkcommand This is an alias for the SERVICEDISPLAYNAME macro.
service.state The service's current state. Can be one of OK, WARNING, CRITICAL and UNKNOWN.
service.stateid The service's current state. Can be one of 0 (ok), 1 (warning), 2 (critical) and 3 (unknown).
service.statetype The service's current state type. Can be one of SOFT and HARD.
service.attempt The current check attempt number.
service.maxattempt The maximum number of checks which are executed before changing to a hard state.
service.laststate The service's previous state. Can be one of OK, WARNING, CRITICAL and UNKNOWN.
service.laststateid The service's previous state. Can be one of 0 (ok), 1 (warning), 2 (critical) and 3 (unknown).
service.laststatetype The service's previous state type. Can be one of SOFT and HARD.
service.laststatechange The last state change's timestamp.
service.durationsec The time since the last state change.
service.latency The service's check latency.
service.executiontime The service's check execution time.
service.output The last check's output.
service.perfdata The last check's performance data.
service.lastcheck The timestamp when the last check was executed.

User Runtime Macros

The following custom attributes are available in all commands that are executed for users:

Name Description
user.name The name of the user object.
user.displayname The value of the display_name attribute.

Notification Runtime Macros

Name Description
notification.type The type of the notification.
notification.author The author of the notification comment, if existing.
notification.comment The comment of the notification, if existing.

Global Runtime Macros

The following macros are available in all executed commands:

Name Description
icinga.timet Current UNIX timestamp.
icinga.longdatetime Current date and time including timezone information. Example: 2014-01-03 11:23:08 +0000
icinga.shortdatetime Current date and time. Example: 2014-01-03 11:23:08
icinga.date Current date. Example: 2014-01-03
icinga.time Current time including timezone information. Example: 11:23:08 +0000