Difference between EC2 and RDS

Question

It seems i do not fully understand the difference between EC2 and RDS. Are both of them separate, or is EC2 like a container for RDS. And also if I want to access RDS, will it go through EC2??

Answer 1

The question is at very high level but however will attempt to answer that.

AWS is all about providing computing infra structure in on demand basis. EC2 and RDS are the 2 different service offerings from AWS.

EC2 : Elastic Compute Cloud - On demand Servers either Linux / Windows.

• You are provided with a Instance to which you can RD / SSH
• You are free to install web server / mail server / db server / app server
• The instance health is AWS's responsibility and everything inside the instance your responsibility

RDS : Relational Database Service

• You are provided with a deployed DB server and you can create the db instance
• You can't do a RD / telnet to connect to the RDS's physical server but you can connect to the RDS instance via clients like SSMS, MySQL workbench etc. or via JDBC / ODBC DB APIs
• You can connect to the RDS instance from any internet enabled client system / application ( provided appropriate firewall rules have been enabled )
• By extension to the previous point, you can connect to the RDS from your app running in EC2.

PS :

• You can install a database server in EC2 and use it / configure as you wish; but remember doing that you will hold the responsibility of the DB's uptime and health as it becomes an app running in the EC2.
• In the RDS, AWS will take care ( manage ) the DB instance health and you just need to concentrate on your data, schema, tables etc.

Answer 2

A simple way to explain this... We need to travel from NYC to Washington DC. How do we go about with it?

The priority is not just reaching the destination;doing a lot of things that are of interest along the way is also needed, then we rent a car; drive it and do all the things that interest you. This is your EC2; This gives you a server box; how you use it is up to you; you can install a database, host a site - the sky is the limit.

If the priority is reaching the destination; you book either a flight or train or bus as per your budget and schedule. This is your RDS. Choose what database you want along with the size and other parameters. Managing the database is the work of Amazon. The Database will be up as per the SLA defined. You have the connection string to access the database from any application.

Hope this clears the air. When you have EC2 box; having a valid license for any software you install is your responsibility; for an RDS instance, there is no license issue for the database - it is factored into the cost.