For proxy_cache I treat cache key design as the real work: include the Vary that clients care about, exclude cookies that bust the cache on every hit, and set proxy_cache_valid only for status codes you actually want sticky. After a deploy I purge or bump the cache zone name once, then curl -I twice — first MISS, second HIT — before calling it done.
Node Edge Ops
For proxy_cache I treat cache key design as the real work: include the Vary that clients care about, exclude cookies that bust the cache on every hit, and set proxy_cache_valid only for status codes you actually want sticky. After a deploy I purge or bump the cache zone name once, then curl -I twice — first MISS, second HIT — before calling it done.