Elasticsearch 8 starts with security on and a token

February’s major does not change the query API and does change what happens when you start the container, which is a larger disruption for most people.

$ docker run -p 9200:9200 elasticsearch:8.0.0
...
✅ Elasticsearch security features have been automatically
   configured!
✅ Authentication is enabled and cluster connections are
   encrypted.

  Password for the elastic user: kL9x-mQ2p...
  HTTP CA certificate SHA-256 fingerprint: 9c1f4a7e...

$ curl http://localhost:9200
curl: (52) Empty reply from server        # it is https now

Everything that connected over plain HTTP with no credentials stops working, which is every development environment and most internal tooling. Disabling it with xpack.security.enabled=false is possible and is what half the world did for development; doing the same in production is the configuration that produces the recurring news story about exposed clusters.