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How conditions are evaluated

Conditions are a set of user-defined rules governing alert triggers and resets.

All child conditions must be satisfied (AND)

Every child condition in the group must be true before the alert is triggered.

In the following example, there are three child conditions.

  • Node Status is equal to Up
  • Percent Loss is greater than or equal to 75
  • CPU Load is greater than or equal to 85

This alert will not trigger unless the Node is Up, packet loss is greater than or equal to 75%, and CPU load is greater than or equal to 85%.

You can also think of the condition as:

Alert when: (Node Status = Up) AND (Percent Loss >= 75) AND (CPU Load >= 85)

At least one child condition must be satisfied (OR)

At least one child condition must be true before the alert is triggered.

In this example the alert trigger reads:

Alert when: (Node Status = Up) OR (Percent Loss >= 75) OR (CPU Load >= 85)

In this situation, if any of the three conditions become true, the alert will trigger.

All child conditions must NOT be satisfied

Every child condition must be false before the alert is triggered.

In this example the alert trigger reads:

Do not alert when: (Node Status = Down) AND (Percent Loss <= 75) AND (CPU Load <= 85)

Alternatively, you can think of the trigger as:

Alert when: (Node Status != Down) AND (Percent Loss > 75) AND (CPU Load > 85)

The conditions have been inverted (Node Status = Down instead of Node Status = Up).

At least one child condition must NOT be satisfied

Any child condition must be false before the alert is triggered.

In this example the alert trigger reads:

Do not alert when: (Node Status = Down) OR (Percent Loss <= 75) OR (CPU Load <= 85)

Alternatively, you can think of the trigger as:

Alert when: (Node Status != Down) OR (Percent Loss > 75) OR (CPU Load > 85)

The conditions have been inverted (Node Status = Down instead of Node Status = Up).