Not entirely clear from the article/blog - is this an RDS instance (equivalent) or EC2 instance (equivalent) in a cloud with storage attached? I didn't think i

Not entirely clear from the article/blog - is this an RDS instance (equivalent) or EC2 instance (equivalent) in a cloud with storage attached? I didn't think it was possible to edit postgres.conf on a RDS type managed database. But the author also talks about scaling up quickly as performance walls are hit while they work on optimizing stuff.