Alerting Policies

Monitoring is only valuable if it leads to action. Alerting policies in Google Cloud Monitoring automatically evaluate metric conditions and notify the right people when thresholds are breached. A well-designed alerting strategy reduces mean time to detection (MTTD), routes incidents to the correct teams, and avoids alert fatigue from noisy, low-value notifications.

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How Alerting Works

An alerting policy consists of three components:

Component	Description
Conditions	The metric-based rules that define when an alert should fire
Notification channels	Where to send the alert (email, Slack, PagerDuty, SMS, etc.)
Documentation	Context and runbook information attached to the alert

Alert Lifecycle

Metric data collected
        |
Condition evaluated (every alignment period)
        |
Threshold breached for duration window
        |
Incident opened --> Notification sent
        |
Condition no longer met
        |
Incident closed --> Resolution notification sent

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Condition Types

Metric Threshold Conditions

The most common condition type. It fires when a metric crosses a threshold for a specified duration: