AWS Service Overview

Amazon Elastic Compute Cloud (EC2) instances are virtual computers on cloud, on which you can install and run applications. 

EC2 has very flexible pricing policies. We can launch servers with applications when needed without upfront commitments, thus eliminating the need to invest in hardware up front and reducing need to forecast. There are also options to reserve servers and get discounts and guarantee.

An Amazon Machine Image (AMI) provides the information required to launch an EC2 instance.  

You specify an AMI when you launch an instance, and you can launch as many instances from the AMI as you need.

You can also launch instances from as many different AMIs as you need.

An AMI includes the following:

1. A template for the root volume for the instance (for example, an operating system, an application server, and applications)

The DynamoDB Storage Backend for Titan is a plug-in that allows you to use DynamoDB as the underlying storage layer for Titan graph database.

It is a client side solution that implements index free adjacency for fast graph traversals on top of DynamoDB.  

Using DynamoDB enables you to run graph workloads without having to manage your own cluster for graph storage.

AWS Lambda is a higher level abstraction that lets you run code without provisioning or managing servers, following the servlerless architecture. You can run code for virtually any type of application or backend service with no administration.

You just needs to upload your code and Lambda takes care of everything required to run and scale your code with high availability, such as server and operating system maintenance, capacity provisioning, automatic scaling, code and security patch deployment, code monitoring and even logging.