gcp-probe

Last updated on Apr 20, 2026

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GCP Cloud Monitoring probe allows you to query Google Cloud Platform monitoring metrics using PromQL and compare the results against specified criteria.

When to use

• Validate GCP infrastructure metrics (e.g., instance CPU utilization, network throughput) during chaos targeting GCP resources
• Use GCP Cloud Monitoring SLOs or custom metrics as experiment pass/fail criteria
• Monitor GKE cluster or Compute Engine instance health via PromQL while running chaos experiments

Prerequisites

• An active GCP account with Cloud Monitoring enabled
• Access to the GCP Cloud Monitoring API from the Kubernetes execution plane
• GCP service account credentials with appropriate permissions (either using Chaos Infra IAM or GCP Service Account Key)

Steps to configure

1. Navigate to Project Settings > Chaos Probes and click + New Probe

2. Select APM Probe, provide a name, and select GCP Cloud Monitoring under APM Type

3. Under Variables, define any reusable values you want to reference in probe properties or run properties. For each variable, specify the type (String or Number), name, value (fixed or runtime input), and whether it's required at runtime.

4. Choose your authentication method:

   Method	Description
   Use Chaos Infra IAM	Uses the service account and workload identity already configured for your chaos infrastructure
   Use GCP Service Account Key	Authenticates using a specific GCP service account key stored in Harness Secret Manager. The service account must have the monitoring.timeSeries.list permission. See GCP Service Account Keys documentation

5. Under Probe Properties, configure:

   Field	Description
   Project ID	Your GCP project ID (e.g., my-gcp-project-123456)
   Query	PromQL query to retrieve metrics from GCP Cloud Monitoring. Example: avg_over_time(compute.googleapis.com/instance/cpu/utilization{instance_name="my-instance"}[5m]). See GCP Cloud Monitoring PromQL docs

   Under GCP Cloud Monitoring Data Comparison, provide:

   Field	Description
   Type	Data type for comparison: Float or Int
   Comparison Criteria	Comparison operator: >=, <=, ==, !=, >, <, oneOf, between
   Value	The expected value to compare against the metric result

6. Provide the Run Properties:

   Field	Description
   Timeout	Maximum time for probe execution (e.g., 10s)
   Interval	Time between successive executions (e.g., 2s)
   Attempt	Number of retry attempts (e.g., 1)
   Polling Interval	Time between retries (e.g., 30s)
   Initial Delay	Delay before first execution (e.g., 5s)
   Verbosity	Log detail level
   Stop On Failure (optional)	Stop the experiment if the probe fails

7. Click Create Probe