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This page explains how to run an experiment in Fault Injection Testing.

Running an experiment involves using an existing template to create an
experiment. The experiment does a dry run where it automatically verifies the
target resources and permissions needed. Once the experiment is ready, you can
proceed with the fault injection.

> [!NOTE]
> **Note:** You cannot start a new experiment if an active [exclusion window](https://docs.cloud.google.com/fault-injection-testing/exclusion-windows.md.txt) covers the target region of your experiment. Any attempts to start an experiment during an active exclusion window will be blocked.

Before proceeding, you must have the `roles/faulttesting.operator` role.

To run an experiment:

1. Select **Experiment templates** from the left-hand navigation and choose a template.
   - (Optional) Enter a custom name for this experiment. If you don't enter an experiment name, it will use the auto-generated one. Example: "template_name_Sep_3_2025".
   - (Optional) Enter a description for this experiment.
2. Select **Start Experiment**.

   A details page showing the progress of the experiment appears, and the dry
   run of the experiment starts.

   When the dry run completes:
   - The target resources appear on the page.
   - The status indicates **Prepared** , meaning that you can start the fault injection. If an experiment is left in the **Prepared** state for more than 10 days, it is automatically canceled.
3. Select **Start injection**. The fault injection starts on the target
   resources, and you can see the progress.