Okay, I understand. I have never heard that being called a stateless cache though, in my experience that is called a public cache. That is also what it is called in the http cache-control standard.

I get what you mean, but calling a cache "stateless" seems like a contradiction in terms to me.

You're talking about HTTP cache control headers, which is a use case that typically avoids storing stateful data in server-side caches. Caches are also used outside of HTTP however, and sometimes those caches can have state (such as expensive database queries). Taking down a cache with state can have a more severe impact on service performance or data consistency.

The blog post mentioned it this way to convey that the cache operation should be relatively simple and generally not return many errors, and that disabling the servers would be low risk (no data loss or severe performance impact).

The cache has state, but it's caching stateless requests.