AWS Inspector2 not running agentless scanning for EC2's with RHEL 8.10

The issue you're experiencing with AWS Inspector2 not running agentless scanning for your EC2 instances with RHEL 8.10 is unexpected, as Red Hat Enterprise Linux 8 is indeed supported for both agentless and agent-based scanning.

To troubleshoot this issue, consider the following points:

1. Verify the exact version: Ensure that the RHEL version is precisely 8.10. Sometimes, minor version differences can cause unexpected behavior.

2. Check instance status: Confirm that the instances have a status of 'Unmanaged EC2 instance', 'Stale inventory', or 'No inventory'. These are required conditions for agentless scanning.

3. File system: You mentioned the file system is xfs, which is one of the supported formats for agentless scanning.

4. EBS and volume requirements: Your instances seem to meet the criteria of having less than 8 volumes and a combined size less than 1200 GB.

5. Exclusion tags: You've confirmed there are no exclusion tags, which is good.

6. Scan frequency: Remember that agentless scans occur every 24 hours for eligible instances. Ensure enough time has passed for a scan to be initiated.

7. IAM roles and permissions: Verify that the instances have the correct IAM roles and permissions for Inspector to access them.

If all these conditions are met and you're still encountering the "Unsupported OS" status, it may be worth considering the following actions:

1. Try enabling agent-based scanning by installing and configuring the SSM agent on your instances.

2. Check the Inspector logs and SSM agent logs (if applicable) for any error messages or clues.

3. Ensure your Inspector is updated to the latest version, as support for newer OS versions might be added in updates.

4. If the problem persists, it would be advisable to contact AWS Support for further assistance, as this appears to be an unexpected behavior given that RHEL 8 is a supported operating system for Inspector2 scans.
   Sources
   Scanning Amazon EC2 instances with Amazon Inspector - Amazon Inspector
   Supported operating systems and programming languages for Amazon Inspector - Amazon Inspector