AWS RDS vs local database in EC2 instance

Question

I want to understand AWS Relational Database Service (RDS) and discover benefits from using it.

Why RDS is better than manually installed PostgreSQL database in EC2 instance?

Is it possible to connent existing database in EC2 instance with Amazon RDS? How it really works?

How I should automation RDS? When I want create new database in existing EC2 instance I can use Ansible in simply way. How I should connect my application with database which uses RDS ?

Thanks in advance!

Answer 1

I want to understand AWS Relational Database Service (RDS) and discover benefits from using it.

As already commented, read the docs and whitepapers.

Why RDS is better than manually installed PostgreSQL database in EC2 instance?

you can be sure it is well setup, you will get point in time recovery , backups and high availability. As well you can set it up yourself, however using RDS you have it all already configured.

Ifs it possible to connent existing database in EC2 instance with Amazon RDS? How it really works?

you don't have access to any underlying configuration, so nope, you cannot really connect ec2 database w/ rds (eg wal for wal streaming).

you still can use database migration tools to migrate all databases and updates to or from rds

How I should automation RDS? When I want create new database in existing EC2 instance I can use Ansible in simply way.

you can use a cloudformation template or cli commands

How I should connect my application with database which uses RDS ?

when you create a rds instance, you will define an admin user and receive a connection url

https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_VPC.Scenarios.html#USER_VPC.Scenario1