1. Proposed title of this feature request

?

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

Customers may try to install metallb on unsupported platforms. See https://metallb.io/installation/clouds/index.html for details.

We should prevent or clearly alert for the issue.

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

He caused a major cluster availability issue, and the root cause was not clear.

4. List any affected packages or components.

metallb when running on, for example, public clouds.