Ask HN: How are modern DBaaS architected?

How are services such as AWS Aurora or DigitalOcean’s Managed Postgres architected? Does anyone know of any whitepapers or blog posts about this topic? My intuition tells me the architecture is something like: 1) User signs up for the product, 2) A control plane level service launches a new instance of Postgres and configures it (on k8s, Nomad, whatever) 3) The database credentials are provided to user and the control plane handles replication/instances/etc. Would love any additional reading or resources anyone can provide.