In order to test, you can take advantage of the fact that any interruption action that Spot Fleet takes on a Spot Instance results in a Spot Instance interruption notice being provided. Therefore, you can simply decrease the target size of your Spot Fleet from 2 to 1. The instance that is interrupted receives the Spot Instance interruption notice.
1. Head to Spot Requests in the EC2 console navigation pane.
2. Select your Spot Fleet request.
3. At the top in the Actions dropdown, select Modify target capacity.
4. Set the New target capacity to 1, and click Submit. This will now reduce the size of the Spot Fleet request target capacity from 2 to 1.
5. Let’s watch the Lambda function in action. Click on Target Groups in the EC2 console navigation pane.
6. Select your Target group.
7. Click on the Targets tab below.
8. In a few moments, you should see one of the Registered targets change status to Draining (you may have to refresh a few times). This is the Spot Instance that is being artificially interrupted by reducing the Spot Fleet target capacity. It will stay in Draining state for 120 seconds based on the configuration set earlier to match the Spot Instance 2 minute interruption notice.