1 # Advanced Topics <a id="advanced-topics"></a>
3 This chapter covers a number of advanced topics. If you're new to Icinga, you
4 can safely skip over things you're not interested in.
6 ## Downtimes <a id="downtimes"></a>
8 Downtimes can be scheduled for planned server maintenance or
9 any other targeted service outage you are aware of in advance.
11 Downtimes will suppress any notifications, and may trigger other
12 downtimes too. If the downtime was set by accident, or the duration
13 exceeds the maintenance, you can manually cancel the downtime.
14 Planned downtimes will also be taken into account for SLA reporting
15 tools calculating the SLAs based on the state and downtime history.
17 Multiple downtimes for a single object may overlap. This is useful
18 when you want to extend your maintenance window taking longer than expected.
19 If there are multiple downtimes triggered for one object, the overall downtime depth
20 will be greater than `1`.
23 If the downtime was scheduled after the problem changed to a critical hard
24 state triggering a problem notification, and the service recovers during
25 the downtime window, the recovery notification won't be suppressed.
27 ### Fixed and Flexible Downtimes <a id="fixed-flexible-downtimes"></a>
29 A `fixed` downtime will be activated at the defined start time, and
30 removed at the end time. During this time window the service state
31 will change to `NOT-OK` and then actually trigger the downtime.
32 Notifications are suppressed and the downtime depth is incremented.
34 Common scenarios are a planned distribution upgrade on your linux
35 servers, or database updates in your warehouse. The customer knows
36 about a fixed downtime window between 23:00 and 24:00. After 24:00
37 all problems should be alerted again. Solution is simple -
38 schedule a `fixed` downtime starting at 23:00 and ending at 24:00.
40 Unlike a `fixed` downtime, a `flexible` downtime will be triggered
41 by the state change in the time span defined by start and end time,
42 and then last for the specified duration in minutes.
44 Imagine the following scenario: Your service is frequently polled
45 by users trying to grab free deleted domains for immediate registration.
46 Between 07:30 and 08:00 the impact will hit for 15 minutes and generate
47 a network outage visible to the monitoring. The service is still alive,
48 but answering too slow to Icinga 2 service checks.
49 For that reason, you may want to schedule a downtime between 07:30 and
50 08:00 with a duration of 15 minutes. The downtime will then last from
51 its trigger time until the duration is over. After that, the downtime
52 is removed (may happen before or after the actual end time!).
54 ### Scheduling a downtime <a id="scheduling-downtime"></a>
56 You can schedule a downtime either by using the Icinga 2 API action
57 [schedule-downtime](12-icinga2-api.md#icinga2-api-actions-schedule-downtime) or
58 by sending an [external command](14-features.md#external-commands).
61 #### Fixed Downtime <a id="fixed-downtime"></a>
63 If the host/service changes into a NOT-OK state between the start and
64 end time window, the downtime will be marked as `in effect` and
65 increases the downtime depth counter.
73 #### Flexible Downtime <a id="flexible-downtime"></a>
75 A flexible downtime defines a time window where the downtime may be
76 triggered from a host/service NOT-OK state change. It will then last
77 until the specified time duration is reached. That way it can happen
78 that the downtime end time is already gone, but the downtime ends
79 at `trigger time + duration`.
84 start | end actual end time
85 |--------------duration--------|
90 ### Triggered Downtimes <a id="triggered-downtimes"></a>
92 This is optional when scheduling a downtime. If there is already a downtime
93 scheduled for a future maintenance, the current downtime can be triggered by
94 that downtime. This renders useful if you have scheduled a host downtime and
95 are now scheduling a child host's downtime getting triggered by the parent
96 downtime on `NOT-OK` state change.
98 ### Recurring Downtimes <a id="recurring-downtimes"></a>
100 [ScheduledDowntime objects](09-object-types.md#objecttype-scheduleddowntime) can be used to set up
101 recurring downtimes for services.
105 apply ScheduledDowntime "backup-downtime" to Service {
106 author = "icingaadmin"
107 comment = "Scheduled downtime for backup"
110 monday = "02:00-03:00"
111 tuesday = "02:00-03:00"
112 wednesday = "02:00-03:00"
113 thursday = "02:00-03:00"
114 friday = "02:00-03:00"
115 saturday = "02:00-03:00"
116 sunday = "02:00-03:00"
119 assign where "backup" in service.groups
123 ## Comments <a id="comments-intro"></a>
125 Comments can be added at runtime and are persistent over restarts. You can
126 add useful information for others on repeating incidents (for example
127 "last time syslog at 100% cpu on 17.10.2013 due to stale nfs mount") which
128 is primarily accessible using web interfaces.
130 You can add a comment either by using the Icinga 2 API action
131 [add-comment](12-icinga2-api.md#icinga2-api-actions-add-comment) or
132 by sending an [external command](14-features.md#external-commands).
134 ## Acknowledgements <a id="acknowledgements"></a>
136 If a problem persists and notifications have been sent, you can
137 acknowledge the problem. That way other users will get
138 a notification that you're aware of the issue and probably are
139 already working on a fix.
141 Note: Acknowledgements also add a new [comment](08-advanced-topics.md#comments-intro)
142 which contains the author and text fields.
144 You can send an acknowledgement either by using the Icinga 2 API action
145 [acknowledge-problem](12-icinga2-api.md#icinga2-api-actions-acknowledge-problem) or
146 by sending an [external command](14-features.md#external-commands).
149 ### Sticky Acknowledgements <a id="sticky-acknowledgements"></a>
151 The acknowledgement is removed if a state change occurs or if the host/service
152 recovers (OK/Up state).
154 If you acknowledge a problem once you've received a `Critical` notification,
155 the acknowledgement will be removed if there is a state transition to `Warning`.
157 OK -> WARNING -> CRITICAL -> WARNING -> OK
160 If you prefer to keep the acknowledgement until the problem is resolved (`OK`
161 recovery) you need to enable the `sticky` parameter.
164 ### Expiring Acknowledgements <a id="expiring-acknowledgements"></a>
166 Once a problem is acknowledged it may disappear from your `handled problems`
167 dashboard and no-one ever looks at it again since it will suppress
170 This `fire-and-forget` action is quite common. If you're sure that a
171 current problem should be resolved in the future at a defined time,
172 you can define an expiration time when acknowledging the problem.
174 Icinga 2 will clear the acknowledgement when expired and start to
175 re-notify, if the problem persists.
178 ## Time Periods <a id="timeperiods"></a>
180 [Time Periods](09-object-types.md#objecttype-timeperiod) define
181 time ranges in Icinga where event actions are triggered, for
182 example whether a service check is executed or not within
183 the `check_period` attribute. Or a notification should be sent to
184 users or not, filtered by the `period` and `notification_period`
185 configuration attributes for `Notification` and `User` objects.
189 > If you are familiar with Icinga 1.x, these time period definitions
190 > are called `legacy timeperiods` in Icinga 2.
192 > An Icinga 2 legacy timeperiod requires the `ITL` provided template
193 >`legacy-timeperiod`.
195 The `TimePeriod` attribute `ranges` may contain multiple directives,
196 including weekdays, days of the month, and calendar dates.
197 These types may overlap/override other types in your ranges dictionary.
199 The descending order of precedence is as follows:
201 * Calendar date (2008-01-01)
202 * Specific month date (January 1st)
203 * Generic month date (Day 15)
204 * Offset weekday of specific month (2nd Tuesday in December)
205 * Offset weekday (3rd Monday)
206 * Normal weekday (Tuesday)
208 If you don't set any `check_period` or `notification_period` attribute
209 on your configuration objects, Icinga 2 assumes `24x7` as time period
212 object TimePeriod "24x7" {
213 import "legacy-timeperiod"
215 display_name = "Icinga 2 24x7 TimePeriod"
217 "monday" = "00:00-24:00"
218 "tuesday" = "00:00-24:00"
219 "wednesday" = "00:00-24:00"
220 "thursday" = "00:00-24:00"
221 "friday" = "00:00-24:00"
222 "saturday" = "00:00-24:00"
223 "sunday" = "00:00-24:00"
227 If your operation staff should only be notified during workhours,
228 create a new timeperiod named `workhours` defining a work day from
231 object TimePeriod "workhours" {
232 import "legacy-timeperiod"
234 display_name = "Icinga 2 8x5 TimePeriod"
236 "monday" = "09:00-17:00"
237 "tuesday" = "09:00-17:00"
238 "wednesday" = "09:00-17:00"
239 "thursday" = "09:00-17:00"
240 "friday" = "09:00-17:00"
244 Furthermore if you wish to specify a notification period across midnight,
245 you can define it the following way:
247 object Timeperiod "across-midnight" {
248 import "legacy-timeperiod"
250 display_name = "Nightly Notification"
252 "saturday" = "22:00-24:00"
253 "sunday" = "00:00-03:00"
257 Below you can see another example for configuring timeperiods across several
258 days, weeks or months. This can be useful when taking components offline
259 for a distinct period of time.
261 object Timeperiod "standby" {
262 import "legacy-timeperiod"
264 display_name = "Standby"
266 "2016-09-30 - 2016-10-30" = "00:00-24:00"
270 Please note that the spaces before and after the dash are mandatory.
272 Once your time period is configured you can Use the `period` attribute
273 to assign time periods to `Notification` and `Dependency` objects:
275 object Notification "mail" {
276 import "generic-notification"
278 host_name = "localhost"
280 command = "mail-notification"
281 users = [ "icingaadmin" ]
285 ### Time Periods Inclusion and Exclusion <a id="timeperiods-includes-excludes"></a>
287 Sometimes it is necessary to exclude certain time ranges from
288 your default time period definitions, for example, if you don't
289 want to send out any notification during the holiday season,
290 or if you only want to allow small time windows for executed checks.
292 The [TimePeriod object](09-object-types.md#objecttype-timeperiod)
293 provides the `includes` and `excludes` attributes to solve this issue.
294 `prefer_includes` defines whether included or excluded time periods are
297 The following example defines a time period called `holidays` where
298 notifications should be suppressed:
300 object TimePeriod "holidays" {
301 import "legacy-timeperiod"
304 "january 1" = "00:00-24:00" //new year's day
305 "july 4" = "00:00-24:00" //independence day
306 "december 25" = "00:00-24:00" //christmas
307 "december 31" = "18:00-24:00" //new year's eve (6pm+)
308 "2017-04-16" = "00:00-24:00" //easter 2017
309 "monday -1 may" = "00:00-24:00" //memorial day (last monday in may)
310 "monday 1 september" = "00:00-24:00" //labor day (1st monday in september)
311 "thursday 4 november" = "00:00-24:00" //thanksgiving (4th thursday in november)
315 In addition to that the time period `weekends` defines an additional
316 time window which should be excluded from notifications:
318 object TimePeriod "weekends-excluded" {
319 import "legacy-timeperiod"
322 "saturday" = "00:00-09:00,18:00-24:00"
323 "sunday" = "00:00-09:00,18:00-24:00"
327 The time period `prod-notification` defines the default time ranges
328 and adds the excluded time period names as an array.
330 object TimePeriod "prod-notification" {
331 import "legacy-timeperiod"
333 excludes = [ "holidays", "weekends-excluded" ]
336 "monday" = "00:00-24:00"
337 "tuesday" = "00:00-24:00"
338 "wednesday" = "00:00-24:00"
339 "thursday" = "00:00-24:00"
340 "friday" = "00:00-24:00"
341 "saturday" = "00:00-24:00"
342 "sunday" = "00:00-24:00"
346 ## External Check Results <a id="external-check-results"></a>
348 Hosts or services which do not actively execute a check plugin to receive
349 the state and output are called "passive checks" or "external check results".
350 In this scenario an external client or script is sending in check results.
352 You can feed check results into Icinga 2 with the following transport methods:
354 * [process-check-result action](12-icinga2-api.md#icinga2-api-actions-process-check-result) available with the [REST API](12-icinga2-api.md#icinga2-api) (remote and local)
355 * External command sent via command pipe (local only)
357 Each time a new check result is received, the next expected check time
358 is updated. This means that if there are no check result received from
359 the external source, Icinga 2 will execute [freshness checks](08-advanced-topics.md#check-result-freshness).
363 > The REST API action allows to specify the `check_source` attribute
364 > which helps identifying the external sender. This is also visible
365 > in Icinga Web 2 and the REST API queries.
367 ## Check Result Freshness <a id="check-result-freshness"></a>
369 In Icinga 2 active check freshness is enabled by default. It is determined by the
370 `check_interval` attribute and no incoming check results in that period of time.
372 The threshold is calculated based on the last check execution time for actively executed checks:
374 (last check execution time + check interval) > current time
376 If this host/service receives check results from an [external source](08-advanced-topics.md#external-check-results),
377 the threshold is based on the last time a check result was received:
379 (last check result time + check interval) > current time
383 > The [process-check-result](12-icinga2-api.md#icinga2-api-actions-process-check-result) REST API
384 > action allows to overrule the pre-defined check interval with a specified TTL in Icinga 2 v2.9+.
386 If the freshness checks fail, Icinga 2 will execute the defined check command.
388 Best practice is to define a [dummy](10-icinga-template-library.md#itl-dummy) `check_command` which gets
389 executed when freshness checks fail.
392 apply Service "external-check" {
393 check_command = "dummy"
396 /* Set the state to UNKNOWN (3) if freshness checks fail. */
399 /* Use a runtime function to retrieve the last check time and more details. */
401 var service = get_service(macro("$host.name$"), macro("$service.name$"))
402 var lastCheck = DateTime(service.last_check).to_string()
404 return "No check results received. Last result time: " + lastCheck
407 assign where "external" in host.vars.services
411 References: [get_service](18-library-reference.md#objref-get_service), [macro](18-library-reference.md#scoped-functions-macro), [DateTime](18-library-reference.md#datetime-type).
413 Example output in Icinga Web 2:
415 ![Icinga 2 Freshness Checks](images/advanced-topics/icinga2_external_checks_freshness_icingaweb2.png)
418 ## Check Flapping <a id="check-flapping"></a>
420 Icinga 2 supports optional detection of hosts and services that are "flapping".
422 Flapping occurs when a service or host changes state too frequently, which would result in a storm of problem and
423 recovery notifications. With flapping detection enabled a flapping notification will be sent while other notifications are
424 suppresed until it calms down after receiving the same status from checks a few times. Flapping detection can help detect
426 configuration problems (wrong thresholds), troublesome services, or network problems.
428 Flapping detection can be enabled or disabled using the `enable_flapping` attribute.
429 The `flapping_threshold_high` and `flapping_threshold_low` attributes allows to specify the thresholds that control
430 when a [host](09-object-types.md#objecttype-host) or [service](objecttype-service) is considered to be flapping.
432 The default thresholds are 30% for high and 25% for low. If the computed flapping value exceeds the high threshold a
433 host or service is considered flapping until it drops below the low flapping threshold.
435 `FlappingStart` and `FlappingEnd` notifications will be sent out accordingly, if configured. See the chapter on
436 [notifications](alert-notifications) for details
438 > Note: There is no distinctions between hard and soft states with flapping. All state changes count and notifications
439 > will be sent out regardless of the objects state.
441 ### How it works <a id="check-flapping-how-it-works"></a>
443 Icinga 2 saves the last 20 state changes for every host and service. See the graphic below:
445 ![Icinga 2 Flapping State Timeline](images/advanced-topics/flapping-state-graph.png)
447 All the states ware weighted, with the most recent one being worth the most (1.15) and the 20th the least (0.8). The
448 states in between are fairly distributed. The final flapping value are the weighted state changes divided by the total
451 In the example above, the added states would have a total value of 7.82 (`0.84 + 0.86 + 0.88 + 0.9 + 0.98 + 1.06 + 1.12 + 1.18`).
452 This yields a flapping percentage of 39.1% (`7.82 / 20 * 100`). As the default upper flapping threshold is 30%, it would be
455 If the next seven check results then would not be state changes, the flapping percentage would fall below the lower threshold
456 of 25% and therefore the host or service would recover from flapping.
458 ## Volatile Services <a id="volatile-services"></a>
460 By default all services remain in a non-volatile state. When a problem
461 occurs, the `SOFT` state applies and once `max_check_attempts` attribute
462 is reached with the check counter, a `HARD` state transition happens.
463 Notifications are only triggered by `HARD` state changes and are then
464 re-sent defined by the `interval` attribute.
466 It may be reasonable to have a volatile service which stays in a `HARD`
467 state type if the service stays in a `NOT-OK` state. That way each
468 service recheck will automatically trigger a notification unless the
469 service is acknowledged or in a scheduled downtime.
471 ## Monitoring Icinga 2 <a id="monitoring-icinga"></a>
473 Why should you do that? Icinga and its components run like any other
474 service application on your server. There are predictable issues
475 such as "disk space is running low" and your monitoring suffers from just
478 You would also like to ensure that features and backends are running
479 and storing required data. Be it the database backend where Icinga Web 2
480 presents fancy dashboards, forwarded metrics to Graphite or InfluxDB or
481 the entire distributed setup.
483 This list isn't complete but should help with your own setup.
484 Windows client specific checks are highlighted.
486 Type | Description | Plugins and CheckCommands
487 ----------------|-------------------------------|-----------------------------------------------------
488 System | Filesystem | [disk](10-icinga-template-library.md#plugin-check-command-disk), [disk-windows](10-icinga-template-library.md#windows-plugins) (Windows Client)
489 System | Memory, Swap | [mem](10-icinga-template-library.md#plugin-contrib-command-mem), [swap](10-icinga-template-library.md#plugin-check-command-swap), [memory](10-icinga-template-library.md#windows-plugins) (Windows Client)
490 System | Hardware | [hpasm](10-icinga-template-library.md#plugin-contrib-command-hpasm), [ipmi-sensor](10-icinga-template-library.md#plugin-contrib-command-ipmi-sensor)
491 System | Virtualization | [VMware](10-icinga-template-library.md#plugin-contrib-vmware), [esxi_hardware](10-icinga-template-library.md#plugin-contrib-command-esxi-hardware)
492 System | Processes | [procs](10-icinga-template-library.md#plugin-check-command-processes), [service-windows](10-icinga-template-library.md#windows-plugins) (Windows Client)
493 System | System Activity Reports | [check_sar_perf](https://github.com/dnsmichi/icinga-plugins/blob/master/scripts/check_sar_perf.py)
494 System | I/O | [iostat](10-icinga-template-library.md#plugin-contrib-command-iostat)
495 System | Network interfaces | [nwc_health](10-icinga-template-library.md#plugin-contrib-command-nwc_health), [interfaces](10-icinga-template-library.md#plugin-contrib-command-interfaces)
496 System | Users | [users](10-icinga-template-library.md#plugin-check-command-users), [users-windows](10-icinga-template-library.md#windows-plugins) (Windows Client)
497 System | Logs | Forward them to [Elastic Stack](14-features.md#elastic-stack-integration) or [Graylog](14-features.md#graylog-integration) and add your own alerts.
498 System | NTP | [ntp_time](10-icinga-template-library.md#plugin-check-command-ntp-time)
499 System | Updates | [apt](10-icinga-template-library.md#plugin-check-command-apt), [yum](10-icinga-template-library.md#plugin-contrib-command-yum)
500 Icinga | Status & Stats | [icinga](10-icinga-template-library.md#itl-icinga) (more below)
501 Icinga | Cluster & Clients | [health checks](06-distributed-monitoring.md#distributed-monitoring-health-checks)
502 Database | MySQL | [mysql_health](10-icinga-template-library.md#plugin-contrib-command-mysql_health)
503 Database | PostgreSQL | [postgres](10-icinga-template-library.md#plugin-contrib-command-postgres)
504 Database | Housekeeping | Check the database size and growth and analyse metrics to examine trends.
505 Database | DB IDO | [ido](10-icinga-template-library.md#itl-icinga-ido) (more below)
506 Webserver | Apache2, Nginx, etc. | [http](10-icinga-template-library.md#plugin-check-command-http), [apache_status](10-icinga-template-library.md#plugin-contrib-command-apache_status), [nginx_status](10-icinga-template-library.md#plugin-contrib-command-nginx_status)
507 Webserver | Certificates | [http](10-icinga-template-library.md#plugin-check-command-http)
508 Webserver | Authorization | [http](10-icinga-template-library.md#plugin-check-command-http)
509 Notifications | Mail (queue) | [smtp](10-icinga-template-library.md#plugin-check-command-smtp), [mailq](10-icinga-template-library.md#plugin-check-command-mailq)
510 Notifications | SMS (GSM modem) | [check_sms3_status](https://exchange.icinga.com/netways/check_sms3status)
511 Notifications | Messengers, Cloud services | XMPP, Twitter, IRC, Telegram, PagerDuty, VictorOps, etc.
512 Metrics | PNP, RRDTool | [check_pnp_rrds](https://github.com/lingej/pnp4nagios/tree/master/scripts) checks for stale RRD files.
513 Metrics | Graphite | [graphite](10-icinga-template-library.md#plugin-contrib-command-graphite)
514 Metrics | InfluxDB | [check_influxdb](https://exchange.icinga.com/Mikanoshi/InfluxDB+data+monitoring+plugin)
515 Metrics | Elastic Stack | [elasticsearch](10-icinga-template-library.md#plugin-contrib-command-elasticsearch), [Elastic Stack integration](14-features.md#elastic-stack-integration)
516 Metrics | Graylog | [Graylog integration](14-features.md#graylog-integration)
519 The [icinga](10-icinga-template-library.md#itl-icinga) CheckCommand provides metrics for the runtime stats of
520 Icinga 2. You can forward them to your preferred graphing solution.
521 If you require more metrics you can also query the [REST API](12-icinga2-api.md#icinga2-api) and write
522 your own custom check plugin. Or you keep using the built-in [object accessor functions](08-advanced-topics.md#access-object-attributes-at-runtime)
523 to calculate stats in-memory.
525 There is a built-in [ido](10-icinga-template-library.md#itl-icinga-ido) check available for DB IDO MySQL/PostgreSQL
526 which provides additional metrics for the IDO database.
529 apply Service "ido-mysql" {
530 check_command = "ido"
532 vars.ido_type = "IdoMysqlConnection"
533 vars.ido_name = "ido-mysql" //the name defined in /etc/icinga2/features-enabled/ido-mysql.conf
535 assign where match("master*.localdomain", host.name)
539 More specific database queries can be found in the [DB IDO](14-features.md#db-ido) chapter.
541 Distributed setups should include specific [health checks](06-distributed-monitoring.md#distributed-monitoring-health-checks).
542 You might also want to add additional checks for SSL certificate expiration.
545 ## Advanced Configuration Hints <a id="advanced-configuration-hints"></a>
547 ### Advanced Use of Apply Rules <a id="advanced-use-of-apply-rules"></a>
549 [Apply rules](03-monitoring-basics.md#using-apply) can be used to create a rule set which is
550 entirely based on host objects and their attributes.
551 In addition to that [apply for and custom attribute override](03-monitoring-basics.md#using-apply-for)
552 extend the possibilities.
554 The following example defines a dictionary on the host object which contains
555 configuration attributes for multiple web servers. This then used to add three checks:
557 * A `ping4` check using the local IP `address` of the web server.
558 * A `tcp` check querying the TCP port where the HTTP service is running on.
559 * If the `url` key is defined, the third apply for rule will create service objects using the `http` CheckCommand.
560 In addition to that you can optionally define the `ssl` attribute which enables HTTPS checks.
564 object Host "webserver01" {
565 import "generic-host"
566 address = "192.168.56.200"
570 instance["status"] = {
571 address = "192.168.56.201"
575 instance["tomcat"] = {
576 address = "192.168.56.202"
579 instance["icingaweb2"] = {
580 address = "192.168.56.210"
588 Service apply for definitions:
590 apply Service "webserver_ping" for (instance => config in host.vars.webserver.instance) {
591 display_name = "webserver_" + instance
592 check_command = "ping4"
594 vars.ping_address = config.address
596 assign where host.vars.webserver.instance
599 apply Service "webserver_port" for (instance => config in host.vars.webserver.instance) {
600 display_name = "webserver_" + instance + "_" + config.port
601 check_command = "tcp"
603 vars.tcp_address = config.address
604 vars.tcp_port = config.port
606 assign where host.vars.webserver.instance
609 apply Service "webserver_url" for (instance => config in host.vars.webserver.instance) {
610 display_name = "webserver_" + instance + "_" + config.url
611 check_command = "http"
613 vars.http_address = config.address
614 vars.http_port = config.port
615 vars.http_uri = config.url
618 vars.http_ssl = config.ssl
621 assign where config.url != ""
624 The variables defined in the host dictionary are not using the typical custom attribute
625 prefix recommended for CheckCommand parameters. Instead they are re-used for multiple
626 service checks in this example.
627 In addition to defining check parameters this way, you can also enrich the `display_name`
628 attribute with more details. This will be shown in in Icinga Web 2 for example.
630 ### Use Functions in Object Configuration <a id="use-functions-object-config"></a>
632 There is a limited scope where functions can be used as object attributes such as:
634 * As value for [Custom Attributes](03-monitoring-basics.md#custom-attributes-functions)
635 * Returning boolean expressions for [set_if](08-advanced-topics.md#use-functions-command-arguments-setif) inside command arguments
636 * Returning a [command](08-advanced-topics.md#use-functions-command-attribute) array inside command objects
638 The other way around you can create objects dynamically using your own global functions.
642 > Functions called inside command objects share the same global scope as runtime macros.
643 > Therefore you can access host custom attributes like `host.vars.os`, or any other
644 > object attribute from inside the function definition used for [set_if](08-advanced-topics.md#use-functions-command-arguments-setif) or [command](08-advanced-topics.md#use-functions-command-attribute).
646 Tips when implementing functions:
648 * Use [log()](18-library-reference.md#global-functions-log) to dump variables. You can see the output
649 inside the `icinga2.log` file depending in your log severity
650 * Use the `icinga2 console` to test basic functionality (e.g. iterating over a dictionary)
651 * Build them step-by-step. You can always refactor your code later on.
653 #### Use Functions in Command Arguments set_if <a id="use-functions-command-arguments-setif"></a>
655 The `set_if` attribute inside the command arguments definition in the
656 [CheckCommand object definition](09-object-types.md#objecttype-checkcommand) is primarily used to
657 evaluate whether the command parameter should be set or not.
659 By default you can evaluate runtime macros for their existence. If the result is not an empty
660 string, the command parameter is passed. This becomes fairly complicated when want to evaluate
661 multiple conditions and attributes.
663 The following example was found on the community support channels. The user had defined a host
664 dictionary named `compellent` with the key `disks`. This was then used inside service apply for rules.
666 object Host "dict-host" {
667 check_command = "check_compellent"
668 vars.compellent["disks"] = {
669 file = "/var/lib/check_compellent/san_disks.0.json",
674 The more significant problem was to only add the command parameter `--disk` to the plugin call
675 when the dictionary `compellent` contains the key `disks`, and omit it if not found.
677 By defining `set_if` as [abbreviated lambda function](17-language-reference.md#nullary-lambdas)
678 and evaluating the host custom attribute `compellent` containing the `disks` this problem was
681 object CheckCommand "check_compellent" {
682 command = [ "/usr/bin/check_compellent" ]
686 var host_vars = host.vars
688 var compel = host_vars.compellent
690 compel.contains("disks")
696 This implementation uses the dictionary type method [contains](18-library-reference.md#dictionary-contains)
697 and will fail if `host.vars.compellent` is not of the type `Dictionary`.
698 Therefore you can extend the checks using the [typeof](17-language-reference.md#types) function.
700 You can test the types using the `icinga2 console`:
703 Icinga (version: v2.3.0-193-g3eb55ad)
704 <1> => srv_vars.compellent["check_a"] = { file="outfile_a.json", checks = [ "disks", "fans" ] }
706 <2> => srv_vars.compellent["check_b"] = { file="outfile_b.json", checks = [ "power", "voltages" ] }
708 <3> => typeof(srv_vars.compellent)
712 The more programmatic approach for `set_if` could look like this:
716 var srv_vars = service.vars
717 if(len(srv_vars) > 0) {
718 if (typeof(srv_vars.compellent) == Dictionary) {
719 return srv_vars.compellent.contains("disks")
721 log(LogInformationen, "checkcommand set_if", "custom attribute compellent_checks is not a dictionary, ignoring it.")
725 log(LogWarning, "checkcommand set_if", "empty custom attributes")
732 #### Use Functions as Command Attribute <a id="use-functions-command-attribute"></a>
734 This comes in handy for [NotificationCommands](09-object-types.md#objecttype-notificationcommand)
735 or [EventCommands](09-object-types.md#objecttype-eventcommand) which does not require
736 a returned checkresult including state/output.
738 The following example was taken from the community support channels. The requirement was to
739 specify a custom attribute inside the notification apply rule and decide which notification
740 script to call based on that.
742 object User "short-dummy" {
745 object UserGroup "short-dummy-group" {
746 assign where user.name == "short-dummy"
749 apply Notification "mail-admins-short" to Host {
750 import "mail-host-notification"
751 command = "mail-host-notification-test"
752 user_groups = [ "short-dummy-group" ]
754 assign where host.vars.notification.mail
757 The solution is fairly simple: The `command` attribute is implemented as function returning
758 an array required by the caller Icinga 2.
759 The local variable `mailscript` sets the default value for the notification scrip location.
760 If the notification custom attribute `short` is set, it will override the local variable `mailscript`
762 The `mailscript` variable is then used to compute the final notification command array being
765 You can omit the `log()` calls, they only help debugging.
767 object NotificationCommand "mail-host-notification-test" {
769 log("command as function")
770 var mailscript = "mail-host-notification-long.sh"
771 if (notification.vars.short) {
772 mailscript = "mail-host-notification-short.sh"
774 log("Running command")
777 var cmd = [ SysconfDir + "/icinga2/scripts/" + mailscript ]
778 log(LogCritical, "me", cmd)
786 #### Use Custom Functions as Attribute <a id="custom-functions-as-attribute"></a>
788 To use custom functions as attributes, the function must be defined in a
789 slightly unexpected way. The following example shows how to assign values
790 depending on group membership. All hosts in the `slow-lan` host group use 300
791 as value for `ping_wrta`, all other hosts use 100.
793 globals.group_specific_value = function(group, group_value, non_group_value) {
794 return function() use (group, group_value, non_group_value) {
795 if (group in host.groups) {
798 return non_group_value
803 apply Service "ping4" {
804 import "generic-service"
805 check_command = "ping4"
807 vars.ping_wrta = group_specific_value("slow-lan", 300, 100)
808 vars.ping_crta = group_specific_value("slow-lan", 500, 200)
813 #### Use Functions in Assign Where Expressions <a id="use-functions-assign-where"></a>
815 If a simple expression for matching a name or checking if an item
816 exists in an array or dictionary does not fit, you should consider
817 writing your own global [functions](17-language-reference.md#functions).
818 You can call them inside `assign where` and `ignore where` expressions
819 for [apply rules](03-monitoring-basics.md#using-apply-expressions) or
820 [group assignments](03-monitoring-basics.md#group-assign-intro) just like
821 any other global functions for example [match](18-library-reference.md#global-functions-match).
823 The following example requires the host `myprinter` being added
824 to the host group `printers-lexmark` but only if the host uses
825 a template matching the name `lexmark*`.
827 template Host "lexmark-printer-host" {
828 vars.printer_type = "Lexmark"
831 object Host "myprinter" {
832 import "generic-host"
833 import "lexmark-printer-host"
835 address = "192.168.1.1"
838 /* register a global function for the assign where call */
839 globals.check_host_templates = function(host, search) {
840 /* iterate over all host templates and check if the search matches */
841 for (tmpl in host.templates) {
842 if (match(search, tmpl)) {
847 /* nothing matched */
851 object HostGroup "printers-lexmark" {
852 display_name = "Lexmark Printers"
853 /* call the global function and pass the arguments */
854 assign where check_host_templates(host, "lexmark*")
858 Take a different more complex example: All hosts with the
859 custom attribute `vars_app` as nested dictionary should be
860 added to the host group `ABAP-app-server`. But only if the
861 `app_type` for all entries is set to `ABAP`.
863 It could read as wildcard match for nested dictionaries:
865 where host.vars.vars_app["*"].app_type == "ABAP"
867 The solution for this problem is to register a global
868 function which checks the `app_type` for all hosts
869 with the `vars_app` dictionary.
871 object Host "appserver01" {
872 check_command = "dummy"
873 vars.vars_app["ABC"] = { app_type = "ABAP" }
875 object Host "appserver02" {
876 check_command = "dummy"
877 vars.vars_app["DEF"] = { app_type = "ABAP" }
880 globals.check_app_type = function(host, type) {
881 /* ensure that other hosts without the custom attribute do not match */
882 if (typeof(host.vars.vars_app) != Dictionary) {
886 /* iterate over the vars_app dictionary */
887 for (key => val in host.vars.vars_app) {
888 /* if the value is a dictionary and if contains the app_type being the requested type */
889 if (typeof(val) == Dictionary && val.app_type == type) {
894 /* nothing matched */
898 object HostGroup "ABAP-app-server" {
899 assign where check_app_type(host, "ABAP")
902 ### Access Object Attributes at Runtime <a id="access-object-attributes-at-runtime"></a>
904 The [Object Accessor Functions](18-library-reference.md#object-accessor-functions)
905 can be used to retrieve references to other objects by name.
907 This allows you to access configuration and runtime object attributes. A detailed
908 list can be found [here](09-object-types.md#object-types).
910 #### Access Object Attributes at Runtime: Cluster Check <a id="access-object-attributes-at-runtime-cluster-check"></a>
912 This is a simple cluster example for accessing two host object states and calculating a virtual
913 cluster state and output:
916 object Host "cluster-host-01" {
917 check_command = "dummy"
919 vars.dummy_text = "This host is down."
922 object Host "cluster-host-02" {
923 check_command = "dummy"
925 vars.dummy_text = "This host is up."
928 object Host "cluster" {
929 check_command = "dummy"
930 vars.cluster_nodes = [ "cluster-host-01", "cluster-host-02" ]
932 vars.dummy_state = {{
935 var cluster_nodes = macro("$cluster_nodes$")
937 for (node in cluster_nodes) {
938 if (get_host(node).state > 0) {
945 if (up_count >= down_count) {
946 return 0 //same up as down -> UP
948 return 2 //something is broken
953 var output = "Cluster hosts:\n"
954 var cluster_nodes = macro("$cluster_nodes$")
956 for (node in cluster_nodes) {
957 output += node + ": " + get_host(node).last_check_result.output + "\n"
965 #### Time Dependent Thresholds <a id="access-object-attributes-at-runtime-time-dependent-thresholds"></a>
967 The following example sets time dependent thresholds for the load check based on the current
968 time of the day compared to the defined time period.
971 object TimePeriod "backup" {
972 import "legacy-timeperiod"
975 monday = "02:00-03:00"
976 tuesday = "02:00-03:00"
977 wednesday = "02:00-03:00"
978 thursday = "02:00-03:00"
979 friday = "02:00-03:00"
980 saturday = "02:00-03:00"
981 sunday = "02:00-03:00"
985 object Host "webserver-with-backup" {
986 check_command = "hostalive"
987 address = "127.0.0.1"
990 object Service "webserver-backup-load" {
991 check_command = "load"
992 host_name = "webserver-with-backup"
994 vars.load_wload1 = {{
995 if (get_time_period("backup").is_inside) {
1001 vars.load_cload1 = {{
1002 if (get_time_period("backup").is_inside) {
1012 ## Advanced Value Types <a id="advanced-value-types"></a>
1014 In addition to the default value types Icinga 2 also uses a few other types
1015 to represent its internal state. The following types are exposed via the [API](12-icinga2-api.md#icinga2-api).
1017 ### CheckResult <a id="advanced-value-types-checkresult"></a>
1019 Name | Type | Description
1020 --------------------------|-----------------------|----------------------------------
1021 exit\_status | Number | The exit status returned by the check execution.
1022 output | String | The check output.
1023 performance\_data | Array | Array of [performance data values](08-advanced-topics.md#advanced-value-types-perfdatavalue).
1024 check\_source | String | Name of the node executing the check.
1025 state | Number | The current state (0 = OK, 1 = WARNING, 2 = CRITICAL, 3 = UNKNOWN).
1026 command | Value | Array of command with shell-escaped arguments or command line string.
1027 execution\_start | Timestamp | Check execution start time (as a UNIX timestamp).
1028 execution\_end | Timestamp | Check execution end time (as a UNIX timestamp).
1029 schedule\_start | Timestamp | Scheduled check execution start time (as a UNIX timestamp).
1030 schedule\_end | Timestamp | Scheduled check execution end time (as a UNIX timestamp).
1031 active | Boolean | Whether the result is from an active or passive check.
1032 vars\_before | Dictionary | Internal attribute used for calculations.
1033 vars\_after | Dictionary | Internal attribute used for calculations.
1034 ttl | Number | Time-to-live duration in seconds for this check result. The next expected check result is `now + ttl` where freshness checks are executed.
1036 ### PerfdataValue <a id="advanced-value-types-perfdatavalue"></a>
1038 Icinga 2 parses performance data strings returned by check plugins and makes the information available to external interfaces (e.g. [GraphiteWriter](09-object-types.md#objecttype-graphitewriter) or the [Icinga 2 API](12-icinga2-api.md#icinga2-api)).
1040 Name | Type | Description
1041 --------------------------|-----------------------|----------------------------------
1042 label | String | Performance data label.
1043 value | Number | Normalized performance data value without unit.
1044 counter | Boolean | Enabled if the original value contains `c` as unit. Defaults to `false`.
1045 unit | String | Unit of measurement (`seconds`, `bytes`. `percent`) according to the [plugin API](05-service-monitoring.md#service-monitoring-plugin-api).
1046 crit | Value | Critical threshold value.
1047 warn | Value | Warning threshold value.
1048 min | Value | Minimum value returned by the check.
1049 max | Value | Maximum value returned by the check.