Changing CentOS in mid-stream

In terms of rebuilders and folk building on Red Hat's labour: Where does Amazon Linux fit into this? From memory and their web pages, it's designed to be binary compatible with Red Hat Enterprise Linux and CentOS as far as possible. Again, I believe that Amazon put large effort into Xen a while ago, so their kernels may be Xen optimised and patched accordingly.

Colleagues suggested - "well, we can just move to Amazon Linux - it's free" but https://aws.amazon.com/amazon-linux-2/faqs/ suggests that the only Linux currently is in the form of virtual machines if you want to run Amazon Linux on premises and there is no support. Out of the frying pan into the fire.

The new AWS Graviton 64 bit ARM instances are probably not running CentOS. Is there anybody with an authoritative viewpoint on this?

We already know from comments further up the stack that FB are apparently using CentOS Streams. Enquiring minds would like to know.