Triggers


While policies and thresholds detect anomalous conditions and display them in the dashboard and the VM data views, they cannot take any actions by themselves. With triggers, you can react to policy and threshold violations and execute a list of configurable actions.

Mechanism

Triggers operate on a different level than policies and thresholds. The latter are configuration options that are applied to single VMs or VM groups. Triggers, on the other hand are not directly coupled to single policy or threshold violations. Rather, they react to sequences of such events that originate from all monitored VMs in a VM group.

This mechanism is intended to give you greater flexibility for deciding what constitutes a condition that requires a particular action. For example, you might expect up to 1 slow URL invocation when a cache is rebuilt. However, if there are 5 slow URL invocations per hour or more, then something is wrong. The definition of what is acceptable and what is not, strongly depends on the type and the implementation of your application.

Time1 hourTime1 hourLimit: 5 policy violations per hourOKFire trigger15

Configuration

In the recording settings, you can edit triggers for each VM group. Triggers operate on all recursively contained VMs. It is possible to define different triggers for a VM group and an ancestor VM group, both sets of triggers are handled separately.

In some cases, triggers are fired too often. For that case, perfino allows you to disable a trigger until you have time to figure out how to change the underlying configuration.

Like for transaction definitions and other entities in perfino, triggers can be saved to and loaded from trigger sets. This enables you to copy and paste trigger definitions as starting points to multiple VM groups.

Trigger types

There are three types of triggers:

Trigger actions

Each trigger can have an arbitrary list of actions.

The types of actions that can be added to a trigger can be ordered into two categories:

The list of actions is executed in order. If one action fails, perfino jumps to next action and does not terminate the execution of the trigger actions.