Why "managed" is worth paying for

You could run it yourself. Should you?

You know how to run PostgreSQL in a Docker container, so you could launch an EC2 instance and do exactly that. Now you own the 3 a.m. problems: applying security patches, taking backups and testing they restore, growing the disk before it fills, and failing over to a replica when the AZ has a bad night.

RDS (Relational Database Service) is AWS running that database for you. You pick an engine (PostgreSQL, MySQL, MariaDB, and others), an instance size (the same t3/m5 types from lesson 3-1, prefixed db.), and RDS handles:

• Automated backups: daily snapshots plus a continuous change log, so you can restore to any minute within the retention window (up to 35 days).
• Patching during a maintenance window you choose.
• Multi-AZ failover: a hot standby copy in another AZ, promoted automatically if the primary dies, usually within a minute or two.

The trade: it costs more than raw EC2 (roughly $13/month for the smallest instance versus $7.50), and you give up root access to the box. For nearly every team, that is a bargain.