Security groups should describe relationships, not addresses
A rule written against a CIDR block encodes an accident of your current network. A rule written against another security group encodes what you actually meant.
Writing / category
Infrastructure
Provisioning, state, drift and the long tail of running cloud infrastructure as code.
K3s is small, not simple
Choosing K3s over managed Kubernetes cut the operational surface substantially and cut the conceptual surface not at all. That distinction is worth understanding before you make the same choice.
Multi-AZ RDS is not automatically correct
It roughly doubles your database cost to buy a synchronous standby. Sometimes that is exactly the right purchase. Deciding it by default is how architecture reviews stop being reviews.