I really enjoy embedding things in the vm. I run a discord bot with a few thousand users with embedded H2. Recently I’ve been looking at trying to embed keycloak (or something similar) for some other apps.
I did that with ES to squeeze performance but IIRC it didn’t really produce meaningful results. Otherwise, for most use cases an integration is better imho than embedding stuff that is when you have a full software service such as keycloack or ES. Rocksdb and h2 are tailor made as embedded libraries
