a lot of things to study before find a solution.

quarkus

• https://quarkus.io/guides/reactive-routes
• https://quarkus.io/guides/reactive-sql-clients

etcd

• https://stackshare.io/stackups/etcd-vs-redis
• https://coreos.com/blog/performance-of-etcd.html

java etcd

• https://github.com/IBM/etcd-java
• https://github.com/etcd-io/jetcd

k8s

• https://www.ovh.it/public-cloud/prices/#compute

lat,lon in memory

• https://guzalexander.com/2018/11/04/java-in-memory-geospatial.html
• https://github.com/kalimatas/geospatial-benchmarks
• https://fribbels.github.io/vptree/writeup
• https://jchambers.github.io/jeospatial/
• https://stackoverflow.com/questions/52302394/poor-lucene-in-memory-spatial-index-performance

apache pulsar

• https://pulsar.apache.org/docs/en/client-libraries-java

test containers

• https://www.testcontainers.org

github actions

• https://rieckpil.de/github-actions-for-java-automate-your-maven-workflows
• https://gist.github.com/faph/20331648cdc0b492eba0f4d83f69eaa5