Amazon Relational Database Concepts
Internal
Relational Database Instance
Database Name
The name of the database the RDS instance will expose. For a PostgreSQL RDBMS, is the name of this database, and it is the value that comes after -d in the psql command line. The database name must begin with a letter and contain only alphanumeric characters. It cannot be "db".
Instance Identifier
The name for the database instance. Can be explicitly specified, in which case CloudFormation converts it to lowercase. If not specified, CloudFormation generates a unique physical ID. Shows up in the endpoint as such: <someid>.ak29cdi3ewg0.ca-central-1.rds.amazonaws.com.
Allocated Storage
Represents the allocated storage size, specified in gigabytes (GB). If any value is set in the Iops parameter, allocated storage must be at least 100 GB, which corresponds to the minimum Iops value of 1,000. If Iops value is increased (in 1,000 IOPS increments), then allocated storage value must be also increased. (in 100-GB increments). The value is required, except when DBClusterIdentifier property is specified or when a read replica is created by using the AWS::RDS::DBInstance resource.
Instance Class
Designates the name of the compute and memory capacity classes for the database instance.
Engine
Engine Version
aws rds describe-db-engine-versions --engine postgres
Master Username
Cannot be "admin" for Postgres.
VPC Association
To make the instance a VPC instance, it must be associated with a DB subnet group.
Security Groups
Note that by default the security group does not allow public access.