Amazon Relational Database Service (Amazon RDS) is a web service that makes it easier to set up, operate, and scale a relational database in the cloud. AWS RDS takes over many of the difficult or tedious management tasks of a relational database. When you use Amazon RDS, you can choose to use on-demand DB instances or reserved DB instances.

Relational Database Types

• SQL Server
• Oracle
• MySQL Server
• PostgreSQL
• Aurora
• MariaDB

What AWS does with RDS?

• When you set up an RDS instance, you get CPU, memory, storage, and IOPS, all bundled together. With Amazon RDS, these are split apart so that you can scale them independently. If you need more CPU, fewer IOPS, or more storage, you can easily allocate them.
• Amazon RDS manages backups, software patching, automatic failure detection, and recovery.
• Since AWS manages RDS instances, Amazon RDS doesn’t provide shell access to DB instances, and it restricts access to certain system procedures and tables that require advanced privileges.
• You can have automated backups performed when you need them, or manually create your own backup snapshot. You can use these backups to restore a database. The Amazon RDS restore process works reliably and efficiently.
• You can get high availability with a primary instance and a synchronous secondary instance that you can fail over to when problems occur. You can also use MySQL, MariaDB, or PostgreSQL Read Replicas to increase read scaling.
• In addition to the security in your database package, you can help control who can access your RDS databases by using AWS Identity and Access Management (IAM) to define users and permissions. You can also help protect your databases by putting them in a virtual private cloud.
• You can create and modify a DB instance by using the AWS Command Line Interface, the Amazon RDS API, or the AWS Management Console.

DB Instances

A DB instance can contain multiple user-created databases, and you can access it by using the same tools and applications that you use with a stand-alone database instance. You can create and modify a DB instance by using the AWS Command Line Interface, the Amazon RDS API, or the AWS Management Console.

You can select the DB instance that best meets your needs. If your needs change over time, you can change DB instances. DB instance storage comes in three types: Magnetic, General Purpose (SSD), and Provisioned IOPS (PIOPS). They differ in performance characteristics and price, allowing you to tailor your storage performance and cost to the needs of your database. 

Security

A security group controls access to a DB instance. It does so by allowing access to IP address ranges or Amazon EC2 instances that you specify.

There are several ways that you can track the performance and health of a DB instance. You can use the free Amazon CloudWatch service to monitor the performance and health of a DB instance; performance charts are shown in the Amazon RDS console. You can subscribe to Amazon RDS events to be notified when changes occur with a DB instance, DB Snapshot, DB parameter group, or DB security group.

RDS with AWS CLI

Get list of database instances

aws rds describe-db-instances

Start a database

aws rds start-db-instance --db-instance-identifier test-instance

Stop a database

aws rds stop-db-instance --db-instance-identifier test-instance

Reboot a database

aws rds reboot-db-instance --db-instance-identifier test-instance

AWS RDS Developer Guide