1. Proposed title of this feature request

Expose a new metric/label that indicates the AMI used by ROSA Classic clusters

2. What is the nature and description of the request?

ROSA Classic clusters worker nodes generally use a special AMI that contain information used by AWS to perform the metering/billing. 

In some cases,  however, Red Hat will perform the metering (via Susbscription Watch) and the worker nodes will be provisioned with a generic AMI instead.

From the OCM perspective, we would like have visibility about which nodes are using the generic AMI (free) vs the ones using marketplace AMI (paid), and we believe that information is suitable for a new prometheus metric or label.

3. Why does the customer need this? (List the business requirements here)

This wouldn't be a customer facing feature. Instead, it would be used by RH internal teams to validate hybrid billing clusters and ensure we are not double charging customers.

4. List any affected packages or components.

Openshift 4.16 and following versions