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 acknowlege 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 supressed:
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
381 If the freshness checks fail, Icinga 2 will execute the defined check command.
383 Best practice is to define a [dummy](10-icinga-template-library.md#plugin-check-command-dummy) `check_command` which gets
384 executed when freshness checks fail.
387 apply Service "external-check" {
388 check_command = "dummy"
391 /* Set the state to UNKNOWN (3) if freshness checks fail. */
394 /* Use a runtime function to retrieve the last check time and more details. */
396 var service = get_service(macro("$host.name$"), macro("$service.name$"))
397 var lastCheck = DateTime(service.last_check).to_string()
399 return "No check results received. Last result time: " + lastCheck
402 assign where "external" in host.vars.services
406 Example output in Icinga Web 2:
408 ![Icinga 2 Freshness Checks](images/advanced-topics/icinga2_external_checks_freshness_icingaweb2.png)
411 ## Check Flapping <a id="check-flapping"></a>
413 Icinga 2 supports optional detection of hosts and services that are "flapping".
415 Flapping occurs when a service or host changes state too frequently, resulting
416 in a storm of problem and recovery notifications. Flapping can be the source of
417 configuration problems (i.e. thresholds set too low), troublesome services,
418 or real network problems.
420 Flapping detection can be enabled or disabled using the `enable_flapping` attribute.
421 The `flapping_threshold` attributes allows to specify the percentage of state changes
422 when a [host](09-object-types.md#objecttype-host) or [service](objecttype-service) is considered to flap.
424 Note: There are known issues with flapping detection. Please refrain from enabling
425 flapping until [#4982](https://github.com/Icinga/icinga2/issues/4982) is fixed.
427 ## Volatile Services <a id="volatile-services"></a>
429 By default all services remain in a non-volatile state. When a problem
430 occurs, the `SOFT` state applies and once `max_check_attempts` attribute
431 is reached with the check counter, a `HARD` state transition happens.
432 Notifications are only triggered by `HARD` state changes and are then
433 re-sent defined by the `interval` attribute.
435 It may be reasonable to have a volatile service which stays in a `HARD`
436 state type if the service stays in a `NOT-OK` state. That way each
437 service recheck will automatically trigger a notification unless the
438 service is acknowledged or in a scheduled downtime.
440 ## Monitoring Icinga 2 <a id="monitoring-icinga"></a>
442 Why should you do that? Icinga and its components run like any other
443 service application on your server. There are predictable issues
444 such as "disk space is running low" and your monitoring suffers from just
447 You would also like to ensure that features and backends are running
448 and storing required data. Be it the database backend where Icinga Web 2
449 presents fancy dashboards, forwarded metrics to Graphite or InfluxDB or
450 the entire distributed setup.
452 This list isn't complete but should help with your own setup.
453 Windows client specific checks are highlighted.
455 Type | Description | Plugins and CheckCommands
456 ----------------|-------------------------------|-----------------------------------------------------
457 System | Filesystem | [disk](10-icinga-template-library.md#plugin-check-command-disk), [disk-windows](10-icinga-template-library.md#windows-plugins) (Windows Client)
458 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)
459 System | Hardware | [hpasm](10-icinga-template-library.md#plugin-contrib-command-hpasm), [ipmi-sensor](10-icinga-template-library.md#plugin-contrib-command-ipmi-sensor)
460 System | Virtualization | [VMware](10-icinga-template-library.md#plugin-contrib-vmware), [esxi_hardware](10-icinga-template-library.md#plugin-contrib-command-esxi-hardware)
461 System | Processes | [procs](10-icinga-template-library.md#plugin-check-command-processes), [service-windows](10-icinga-template-library.md#windows-plugins) (Windows Client)
462 System | System Activity Reports | [check_sar_perf](https://github.com/dnsmichi/icinga-plugins/blob/master/scripts/check_sar_perf.py)
463 System | I/O | [iostat](10-icinga-template-library.md#plugin-contrib-command-iostat)
464 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)
465 System | Users | [users](10-icinga-template-library.md#plugin-check-command-users), [users-windows](10-icinga-template-library.md#windows-plugins) (Windows Client)
466 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.
467 System | NTP | [ntp_time](10-icinga-template-library.md#plugin-check-command-ntp-time)
468 System | Updates | [apt](10-icinga-template-library.md#plugin-check-command-apt), [yum](10-icinga-template-library.md#plugin-contrib-command-yum)
469 Icinga | Status & Stats | [icinga](10-icinga-template-library.md#itl-icinga) (more below)
470 Icinga | Cluster & Clients | [health checks](06-distributed-monitoring.md#distributed-monitoring-health-checks)
471 Database | MySQL | [mysql_health](10-icinga-template-library.md#plugin-contrib-command-mysql_health)
472 Database | PostgreSQL | [postgres](10-icinga-template-library.md#plugin-contrib-command-postgres)
473 Database | Housekeeping | Check the database size and growth and analyse metrics to examine trends.
474 Database | DB IDO | [ido](10-icinga-template-library.md#itl-icinga-ido) (more below)
475 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)
476 Webserver | Certificates | [http](10-icinga-template-library.md#plugin-check-command-http)
477 Webserver | Authorization | [http](10-icinga-template-library.md#plugin-check-command-http)
478 Notifications | Mail (queue) | [smtp](10-icinga-template-library.md#plugin-check-command-smtp), [mailq](10-icinga-template-library.md#plugin-check-command-mailq)
479 Notifications | SMS (GSM modem) | [check_sms3_status](https://exchange.icinga.com/netways/check_sms3status)
480 Notifications | Messengers, Cloud services | XMPP, Twitter, IRC, Telegram, PagerDuty, VictorOps, etc.
481 Metrics | PNP, RRDTool | [check_pnp_rrds](https://github.com/lingej/pnp4nagios/tree/master/scripts) checks for stale RRD files.
482 Metrics | Graphite | [graphite](10-icinga-template-library.md#plugin-contrib-command-graphite)
483 Metrics | InfluxDB | [check_influxdb](https://exchange.icinga.com/Mikanoshi/InfluxDB+data+monitoring+plugin)
484 Metrics | Elastic Stack | [elasticsearch](10-icinga-template-library.md#plugin-contrib-command-elasticsearch), [Elastic Stack integration](14-features.md#elastic-stack-integration)
485 Metrics | Graylog | [Graylog integration](14-features.md#graylog-integration)
488 The [icinga](10-icinga-template-library.md#itl-icinga) CheckCommand provides metrics for the runtime stats of
489 Icinga 2. You can forward them to your preferred graphing solution.
490 If you require more metrics you can also query the [REST API](12-icinga2-api.md#icinga2-api) and write
491 your own custom check plugin. Or you keep using the built-in [object accessor functions](08-advanced-topics.md#access-object-attributes-at-runtime)
492 to calculate stats in-memory.
494 There is a built-in [ido](10-icinga-template-library.md#itl-icinga-ido) check available for DB IDO MySQL/PostgreSQL
495 which provides additional metrics for the IDO database.
498 apply Service "ido-mysql" {
499 check_command = "ido"
501 vars.ido_type = "IdoMysqlConnection"
502 vars.ido_name = "ido-mysql" //the name defined in /etc/icinga2/features-enabled/ido-mysql.conf
504 assign where match("master*.localdomain", host.name)
508 More specific database queries can be found in the [DB IDO](14-features.md#db-ido) chapter.
510 Distributed setups should include specific [health checks](06-distributed-monitoring.md#distributed-monitoring-health-checks).
511 You might also want to add additional checks for SSL certificate expiration.
514 ## Advanced Configuration Hints <a id="advanced-configuration-hints"></a>
516 ### Advanced Use of Apply Rules <a id="advanced-use-of-apply-rules"></a>
518 [Apply rules](03-monitoring-basics.md#using-apply) can be used to create a rule set which is
519 entirely based on host objects and their attributes.
520 In addition to that [apply for and custom attribute override](03-monitoring-basics.md#using-apply-for)
521 extend the possibilities.
523 The following example defines a dictionary on the host object which contains
524 configuration attributes for multiple web servers. This then used to add three checks:
526 * A `ping4` check using the local IP `address` of the web server.
527 * A `tcp` check querying the TCP port where the HTTP service is running on.
528 * If the `url` key is defined, the third apply for rule will create service objects using the `http` CheckCommand.
529 In addition to that you can optionally define the `ssl` attribute which enables HTTPS checks.
533 object Host "webserver01" {
534 import "generic-host"
535 address = "192.168.56.200"
539 instance["status"] = {
540 address = "192.168.56.201"
544 instance["tomcat"] = {
545 address = "192.168.56.202"
548 instance["icingaweb2"] = {
549 address = "192.168.56.210"
557 Service apply for definitions:
559 apply Service "webserver_ping" for (instance => config in host.vars.webserver.instance) {
560 display_name = "webserver_" + instance
561 check_command = "ping4"
563 vars.ping_address = config.address
565 assign where host.vars.webserver.instance
568 apply Service "webserver_port" for (instance => config in host.vars.webserver.instance) {
569 display_name = "webserver_" + instance + "_" + config.port
570 check_command = "tcp"
572 vars.tcp_address = config.address
573 vars.tcp_port = config.port
575 assign where host.vars.webserver.instance
578 apply Service "webserver_url" for (instance => config in host.vars.webserver.instance) {
579 display_name = "webserver_" + instance + "_" + config.url
580 check_command = "http"
582 vars.http_address = config.address
583 vars.http_port = config.port
584 vars.http_uri = config.url
587 vars.http_ssl = config.ssl
590 assign where config.url != ""
593 The variables defined in the host dictionary are not using the typical custom attribute
594 prefix recommended for CheckCommand parameters. Instead they are re-used for multiple
595 service checks in this example.
596 In addition to defining check parameters this way, you can also enrich the `display_name`
597 attribute with more details. This will be shown in in Icinga Web 2 for example.
599 ### Use Functions in Object Configuration <a id="use-functions-object-config"></a>
601 There is a limited scope where functions can be used as object attributes such as:
603 * As value for [Custom Attributes](03-monitoring-basics.md#custom-attributes-functions)
604 * Returning boolean expressions for [set_if](08-advanced-topics.md#use-functions-command-arguments-setif) inside command arguments
605 * Returning a [command](08-advanced-topics.md#use-functions-command-attribute) array inside command objects
607 The other way around you can create objects dynamically using your own global functions.
611 > Functions called inside command objects share the same global scope as runtime macros.
612 > Therefore you can access host custom attributes like `host.vars.os`, or any other
613 > 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).
615 Tips when implementing functions:
617 * Use [log()](18-library-reference.md#global-functions-log) to dump variables. You can see the output
618 inside the `icinga2.log` file depending in your log severity
619 * Use the `icinga2 console` to test basic functionality (e.g. iterating over a dictionary)
620 * Build them step-by-step. You can always refactor your code later on.
622 #### Use Functions in Command Arguments set_if <a id="use-functions-command-arguments-setif"></a>
624 The `set_if` attribute inside the command arguments definition in the
625 [CheckCommand object definition](09-object-types.md#objecttype-checkcommand) is primarily used to
626 evaluate whether the command parameter should be set or not.
628 By default you can evaluate runtime macros for their existence. If the result is not an empty
629 string, the command parameter is passed. This becomes fairly complicated when want to evaluate
630 multiple conditions and attributes.
632 The following example was found on the community support channels. The user had defined a host
633 dictionary named `compellent` with the key `disks`. This was then used inside service apply for rules.
635 object Host "dict-host" {
636 check_command = "check_compellent"
637 vars.compellent["disks"] = {
638 file = "/var/lib/check_compellent/san_disks.0.json",
643 The more significant problem was to only add the command parameter `--disk` to the plugin call
644 when the dictionary `compellent` contains the key `disks`, and omit it if not found.
646 By defining `set_if` as [abbreviated lambda function](17-language-reference.md#nullary-lambdas)
647 and evaluating the host custom attribute `compellent` containing the `disks` this problem was
650 object CheckCommand "check_compellent" {
651 command = [ "/usr/bin/check_compellent" ]
655 var host_vars = host.vars
657 var compel = host_vars.compellent
659 compel.contains("disks")
665 This implementation uses the dictionary type method [contains](18-library-reference.md#dictionary-contains)
666 and will fail if `host.vars.compellent` is not of the type `Dictionary`.
667 Therefore you can extend the checks using the [typeof](17-language-reference.md#types) function.
669 You can test the types using the `icinga2 console`:
672 Icinga (version: v2.3.0-193-g3eb55ad)
673 <1> => srv_vars.compellent["check_a"] = { file="outfile_a.json", checks = [ "disks", "fans" ] }
675 <2> => srv_vars.compellent["check_b"] = { file="outfile_b.json", checks = [ "power", "voltages" ] }
677 <3> => typeof(srv_vars.compellent)
681 The more programmatic approach for `set_if` could look like this:
685 var srv_vars = service.vars
686 if(len(srv_vars) > 0) {
687 if (typeof(srv_vars.compellent) == Dictionary) {
688 return srv_vars.compellent.contains("disks")
690 log(LogInformationen, "checkcommand set_if", "custom attribute compellent_checks is not a dictionary, ignoring it.")
694 log(LogWarning, "checkcommand set_if", "empty custom attributes")
701 #### Use Functions as Command Attribute <a id="use-functions-command-attribute"></a>
703 This comes in handy for [NotificationCommands](09-object-types.md#objecttype-notificationcommand)
704 or [EventCommands](09-object-types.md#objecttype-eventcommand) which does not require
705 a returned checkresult including state/output.
707 The following example was taken from the community support channels. The requirement was to
708 specify a custom attribute inside the notification apply rule and decide which notification
709 script to call based on that.
711 object User "short-dummy" {
714 object UserGroup "short-dummy-group" {
715 assign where user.name == "short-dummy"
718 apply Notification "mail-admins-short" to Host {
719 import "mail-host-notification"
720 command = "mail-host-notification-test"
721 user_groups = [ "short-dummy-group" ]
723 assign where host.vars.notification.mail
726 The solution is fairly simple: The `command` attribute is implemented as function returning
727 an array required by the caller Icinga 2.
728 The local variable `mailscript` sets the default value for the notification scrip location.
729 If the notification custom attribute `short` is set, it will override the local variable `mailscript`
731 The `mailscript` variable is then used to compute the final notification command array being
734 You can omit the `log()` calls, they only help debugging.
736 object NotificationCommand "mail-host-notification-test" {
738 log("command as function")
739 var mailscript = "mail-host-notification-long.sh"
740 if (notification.vars.short) {
741 mailscript = "mail-host-notification-short.sh"
743 log("Running command")
746 var cmd = [ SysconfDir + "/icinga2/scripts/" + mailscript ]
747 log(LogCritical, "me", cmd)
755 #### Use Custom Functions as Attribute <a id="custom-functions-as-attribute"></a>
757 To use custom functions as attributes, the function must be defined in a
758 slightly unexpected way. The following example shows how to assign values
759 depending on group membership. All hosts in the `slow-lan` host group use 300
760 as value for `ping_wrta`, all other hosts use 100.
762 globals.group_specific_value = function(group, group_value, non_group_value) {
763 return function() use (group, group_value, non_group_value) {
764 if (group in host.groups) {
767 return non_group_value
772 apply Service "ping4" {
773 import "generic-service"
774 check_command = "ping4"
776 vars.ping_wrta = group_specific_value("slow-lan", 300, 100)
777 vars.ping_crta = group_specific_value("slow-lan", 500, 200)
782 #### Use Functions in Assign Where Expressions <a id="use-functions-assign-where"></a>
784 If a simple expression for matching a name or checking if an item
785 exists in an array or dictionary does not fit, you should consider
786 writing your own global [functions](17-language-reference.md#functions).
787 You can call them inside `assign where` and `ignore where` expressions
788 for [apply rules](03-monitoring-basics.md#using-apply-expressions) or
789 [group assignments](03-monitoring-basics.md#group-assign-intro) just like
790 any other global functions for example [match](18-library-reference.md#global-functions-match).
792 The following example requires the host `myprinter` being added
793 to the host group `printers-lexmark` but only if the host uses
794 a template matching the name `lexmark*`.
796 template Host "lexmark-printer-host" {
797 vars.printer_type = "Lexmark"
800 object Host "myprinter" {
801 import "generic-host"
802 import "lexmark-printer-host"
804 address = "192.168.1.1"
807 /* register a global function for the assign where call */
808 globals.check_host_templates = function(host, search) {
809 /* iterate over all host templates and check if the search matches */
810 for (tmpl in host.templates) {
811 if (match(search, tmpl)) {
816 /* nothing matched */
820 object HostGroup "printers-lexmark" {
821 display_name = "Lexmark Printers"
822 /* call the global function and pass the arguments */
823 assign where check_host_templates(host, "lexmark*")
827 Take a different more complex example: All hosts with the
828 custom attribute `vars_app` as nested dictionary should be
829 added to the host group `ABAP-app-server`. But only if the
830 `app_type` for all entries is set to `ABAP`.
832 It could read as wildcard match for nested dictionaries:
834 where host.vars.vars_app["*"].app_type == "ABAP"
836 The solution for this problem is to register a global
837 function which checks the `app_type` for all hosts
838 with the `vars_app` dictionary.
840 object Host "appserver01" {
841 check_command = "dummy"
842 vars.vars_app["ABC"] = { app_type = "ABAP" }
844 object Host "appserver02" {
845 check_command = "dummy"
846 vars.vars_app["DEF"] = { app_type = "ABAP" }
849 globals.check_app_type = function(host, type) {
850 /* ensure that other hosts without the custom attribute do not match */
851 if (typeof(host.vars.vars_app) != Dictionary) {
855 /* iterate over the vars_app dictionary */
856 for (key => val in host.vars.vars_app) {
857 /* if the value is a dictionary and if contains the app_type being the requested type */
858 if (typeof(val) == Dictionary && val.app_type == type) {
863 /* nothing matched */
867 object HostGroup "ABAP-app-server" {
868 assign where check_app_type(host, "ABAP")
871 ### Access Object Attributes at Runtime <a id="access-object-attributes-at-runtime"></a>
873 The [Object Accessor Functions](18-library-reference.md#object-accessor-functions)
874 can be used to retrieve references to other objects by name.
876 This allows you to access configuration and runtime object attributes. A detailed
877 list can be found [here](09-object-types.md#object-types).
879 Simple cluster example for accessing two host object states and calculating a virtual
880 cluster state and output:
882 object Host "cluster-host-01" {
883 check_command = "dummy"
885 vars.dummy_text = "This host is down."
888 object Host "cluster-host-02" {
889 check_command = "dummy"
891 vars.dummy_text = "This host is up."
894 object Host "cluster" {
895 check_command = "dummy"
896 vars.cluster_nodes = [ "cluster-host-01", "cluster-host-02" ]
898 vars.dummy_state = {{
901 var cluster_nodes = macro("$cluster_nodes$")
903 for (node in cluster_nodes) {
904 if (get_host(node).state > 0) {
911 if (up_count >= down_count) {
912 return 0 //same up as down -> UP
914 return 2 //something is broken
919 var output = "Cluster hosts:\n"
920 var cluster_nodes = macro("$cluster_nodes$")
922 for (node in cluster_nodes) {
923 output += node + ": " + get_host(node).last_check_result.output + "\n"
931 The following example sets time dependent thresholds for the load check based on the current
932 time of the day compared to the defined time period.
934 object TimePeriod "backup" {
935 import "legacy-timeperiod"
938 monday = "02:00-03:00"
939 tuesday = "02:00-03:00"
940 wednesday = "02:00-03:00"
941 thursday = "02:00-03:00"
942 friday = "02:00-03:00"
943 saturday = "02:00-03:00"
944 sunday = "02:00-03:00"
948 object Host "webserver-with-backup" {
949 check_command = "hostalive"
950 address = "127.0.0.1"
953 object Service "webserver-backup-load" {
954 check_command = "load"
955 host_name = "webserver-with-backup"
957 vars.load_wload1 = {{
958 if (get_time_period("backup").is_inside) {
964 vars.load_cload1 = {{
965 if (get_time_period("backup").is_inside) {