Alerting policies in GCP - Commands & Configuration

Introduction

Alerting policies help you get notified when something important happens in your cloud resources. They watch metrics or logs and send alerts so you can fix problems quickly.

When you want to know if your website is down or slow

When your server CPU usage goes too high for too long

When a storage bucket is almost full

When an error rate in your application increases suddenly

When you want to get notified by email or SMS about critical issues

Config File - alert_policy.yaml

alert_policy.yaml

displayName: "High CPU Usage Alert"
combiner: "OR"
conditions:
- displayName: "CPU usage above 80%"
  conditionThreshold:
    filter: "metric.type=\"compute.googleapis.com/instance/cpu/utilization\""
    comparison: COMPARISON_GT
    thresholdValue: 0.8
    duration: "300s"
    trigger:
      count: 1
notificationChannels:
- projects/my-project/notificationChannels/1234567890
enabled: true

displayName: The name of the alert policy.

combiner: How multiple conditions combine (OR means alert if any condition is true).

conditions: What metric to watch and the threshold to trigger alert.

notificationChannels: Where to send alerts (email, SMS, etc.).

enabled: Whether the alert is active.

Commands

This command creates an alerting policy in Google Cloud Monitoring using the configuration file. It sets up the alert to watch CPU usage and notify when it goes above 80%.

Terminal

gcloud monitoring policies create --policy-from-file=alert_policy.yaml

Expected Output

Created alerting policy: projects/my-project/alertPolicies/9876543210

→

--policy-from-file - Specifies the YAML file that defines the alerting policy

This command lists all alerting policies in your project so you can verify the new policy was created.

Terminal

gcloud monitoring policies list

Expected Output

NAME                  DISPLAY NAME           ENABLED

9876543210            High CPU Usage Alert   True

This command shows detailed information about the alerting policy to check its settings and conditions.

Terminal

gcloud monitoring policies describe 9876543210

Expected Output

name: projects/my-project/alertPolicies/9876543210

displayName: High CPU Usage Alert

combiner: OR

conditions:

- displayName: CPU usage above 80%

  conditionThreshold:

    filter: metric.type="compute.googleapis.com/instance/cpu/utilization"

    comparison: COMPARISON_GT

    thresholdValue: 0.8

    duration: 300s

    trigger:

      count: 1

notificationChannels:

- projects/my-project/notificationChannels/1234567890

enabled: true

Key Concept

If you remember nothing else from this pattern, remember: alerting policies watch your cloud metrics and notify you automatically when something needs your attention.

Common Mistakes

Not enabling the alerting policy after creating it

The alert will not send notifications if the policy is disabled.

Make sure the 'enabled' field is set to true in the policy configuration.

Using incorrect metric filter syntax in the condition

The alert will never trigger because it is not watching the right metric.

Use the exact metric type string from Google Cloud Monitoring documentation, like "compute.googleapis.com/instance/cpu/utilization".

Not specifying notification channels

Alerts will trigger but no one will be notified without notification channels.

Create notification channels in Google Cloud Console and include their IDs in the policy.

Summary

Create an alerting policy YAML file defining the metric, threshold, and notifications.

Use gcloud CLI to create the alerting policy from the YAML file.

List and describe policies to verify the alert is set up correctly and enabled.