1 Configuring a trigger

Overview

Click on Triggers in the row of the host
Enter parameters of the trigger in the form

See also on triggers and their calculation times.

Configuration

The Trigger tab contains all the essential trigger attributes.

All mandatory input fields are marked with a red asterisk.

The Tags tab allows you to define trigger-level . All problems of this trigger will be tagged with the values entered here.

Parameter Description

Name/Value Set custom tags to mark trigger events.
Tags are a pair of tag name and value. You can use only the name or pair it with a value. A trigger may have several tags with the same name, but different values.
User macros, user macro context, low-level discovery macros and macro functions with , {{ITEM.LASTVALUE}} and low-level discovery macros are supported in event tags. Low-level discovery macros can be used inside macro context.
{TRIGGER.ID} macro is supported in trigger tag values. It may be useful for identifying triggers created from trigger prototypes and, for example, suppressing problems from these triggers during maintenance.
If the total length of expanded value exceeds 255, it will be cut to 255 characters.
See all supported for event tags.
Event tags can be used for event correlation, in action conditions and will also be seen in Monitoring → Problems or the Problems widget.

Parameter	Description
Name/Value	Set custom tags to mark trigger events. Tags are a pair of tag name and value. You can use only the name or pair it with a value. A trigger may have several tags with the same name, but different values. User macros, user macro context, low-level discovery macros and macro functions with , `{{ITEM.LASTVALUE}}` and low-level discovery macros are supported in event tags. Low-level discovery macros can be used inside macro context. {TRIGGER.ID} macro is supported in trigger tag values. It may be useful for identifying triggers created from trigger prototypes and, for example, suppressing problems from these triggers during maintenance. If the total length of expanded value exceeds 255, it will be cut to 255 characters. See all supported for event tags. Event tags can be used for event correlation, in action conditions and will also be seen in Monitoring → Problems or the Problems widget.

The Dependencies tab contains all the of the trigger.

Click on Add to add a new dependency.

You can also configure a trigger by opening an existing one, pressing the Clone button and then saving under a different name.

Testing expressions

It is possible to test the configured trigger expression as to what the expression result would be depending on the received value.

The following expression from an official template is taken as an example:

To test the expression, click on Expression constructor under the expression field.

In the Expression constructor, all individual expressions are listed. To open the testing window, click on Test below the expression list.

In the testing window you can enter sample values (‘80’, ‘70’, ‘0’, ‘1’ in this example) and then see the expression result, by clicking on the Test button.

The result of the individual expressions as well as the whole expression can be seen.

“TRUE” means that the specified expression is correct. In this particular case A, “80” is greater than the {$TEMP_WARN} specified value, “70” in this example. As expected, a “TRUE” result appears.

The chosen expression type is “OR”. If at least one of the specified conditions (A or B in this case) is TRUE, the overall result will be TRUE as well. Meaning that the current value exceeds the warning value and a problem has occurred.