The Answer Is Postgres; the Question Is How?

I'm not 100% positive about Hetzner, but suspect much of it is is actually on a VM, and would indeed be old standard. Back at Heroku we were in the very early days of carving up databases within containers. Containers themselves very much were not mature enough at the time (10 years ago), but the underlying primitives of lxc and cgroups we could mostly get to work. At the time though, and this was still just 10-12 years ago we had people actively debate that VMs on AWS weren't suitable for databases...