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# 4 New trigger

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#### Overview

In this section you will learn how to set up a trigger.

Items only collect data. To automatically evaluate incoming data we need to define triggers.
A trigger contains an expression that defines a threshold of what is an acceptable level for the data.

If that level is surpassed by the incoming data, a trigger will "fire" or go into a 'Problem' state - indicating that something has happened that may require attention.
If the level is acceptable again, trigger returns to an 'Ok' state.

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#### Adding trigger

To configure a trigger for our item:

1. Go to *Data collection > Hosts*.
2. Click the *Triggers* link in the row of 'New host'.
3. Click *Create trigger*.

A trigger configuration form is opened.

![](../../../../assets/en/manual/quickstart/new_trigger.png){width="600"}

For our trigger, the essential information to enter here is:

*Name*

-   Enter *CPU load too high on 'New host' for 3 minutes* as the value.
    This will be the trigger name displayed in lists and elsewhere.

*Expression*

-   Enter: `avg(/New host/system.cpu.load,3m)>2`

This is the trigger expression.
Make sure that the expression is entered right, down to the last symbol.
The item key here (`system.cpu.load`) is used to refer to the item.
This particular expression basically says that the problem threshold is exceeded when the CPU load average value for 3 minutes is over 2.
You can learn more about the [syntax of trigger expressions](/manual/config/triggers/expression).

[Other options](/manual/config/triggers/trigger#configuration) may be left unchanged, using their default values.

When done, click *Add*.
The new trigger should appear in the trigger list.

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#### Displaying trigger status

With a trigger defined, you might be interested to see its status.

If the CPU load has exceeded the threshold level you defined in the trigger, the problem will be displayed in *Monitoring > Problems*.

![](../../../../assets/en/manual/quickstart/trigger_status0.png){width="600"}

The flashing in the status column indicates a recent change of trigger status, one that has taken place in the last 30 minutes.

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