Flynn co-founder here. We plan to expand to support many more popular open source databases next year (and expose a framework for others to do the same). The goal is that a supported database should "just work" on the platform and be sanely configured out of the box with high availability, automatic failover/recovery, encrypted streaming backups, app credential provisioning, etc.

Our Postgres appliance is unique in that it is explicitly designed to not lose data in the face of failure. Simply wrapping up a database in a container with leader election and replication is not enough, as there are many pitfalls that can cause data to be lost during failures. Of course we are limited by the guarantees the database can provide, so some datastore appliances we build may have clearly defined caveats.

Storing binary blobs is another tricky matter, and we're exploring what we can do with little to no configuration. We currently store app images and git repos in Postgres, which works but will only scale so far.

We are also improving our scheduler so that it is capable of providing the constraints necessary to place stateful services properly.