Ask HN: How would you approach horizontal scaling of your software?

Hi, I'm currently thinking about how to best implement partitioning/replication of my Open Source storage system written in Java. I've read "Designing Data-Intensive Applications: The Big Ideas Behind Reliable, Scalable, and Maintainable Systems" which is a great book, but I'd love more resources. At work we basically used Ignite for our application and horizontal scaling in the Cloud with a distributed file system, but the latter is something I clearly want to avoid. So, do you have some resources/tips? I clearly want to have transactions based on some consensus algorithm and a single leader, which accepts writes. But basically I want to read more about the whole topic before moving forward and develop epics/tasks. Do you have any resources / best practices? Nowadays it seems that almost everyone puts his software into the cloud via Docker/Kubernetes and some data grid, but I guess it's still complicated to do it right :-) Kind regards and happy easter Johannes