Understand IMDSv2 Metrics:

IMDSv2 adds a layer of security to EC2 instance metadata by requiring a session token.

TheEC2MetadataNoTokenCloudWatch metric tracks the number of calls to IMDSv1.

Enable the IMDS Metrics:

Ensure that the EC2 instances have theDetailed Monitoringfeature enabled to publish metrics to CloudWatch.

Create a CloudWatch Dashboard:

In the CloudWatch console, create a dashboard that displays theEC2MetadataNoTokenmetric for all instances.

Verify Zero Value:

Monitor theEC2MetadataNoTokenmetric. If the value is zero for all instances, it confirms that IMDSv1 is no longer in use.

Secure Access and Validation:

Regularly monitor the dashboard to ensure no instance reverts to using IMDSv1.

Instance Metadata Service (IMDS) Documentation

CloudWatch Metrics for EC2 Instances

AWS Security Best Practices for Metadata Service