• Elastic—Amazon EC2 enables you to increase or decrease capacity within minutes, not hours or days. You can commission one, hundreds or even thousands of server instances simultaneously. Of course, because this is all controlled with web service APIs, your application can automatically scale itself up and down depending on its needs.

• Completely Controlled—You have complete control of your instances. You have root access to each one, and you can interact with them as you would any machine. Instances can be rebooted remotely using web service APIs. You also have access to console output of your instances.

• Flexible—You have the choice of several instance types, allowing you to select a configuration of memory, CPU, operating system, and instance storage that is optimal for your application.

• Designed for use with other Amazon Web Services—Amazon EC2 works in conjunction with Amazon Simple Storage Service (Amazon S3), Amazon SimpleDB and Amazon Simple Queue Service (Amazon SQS) to provide a complete solution for computing, query processing and storage across a wide range of applications.

• Reliable—Amazon EC2 offers a highly reliable environment where replacement instances can be rapidly and reliably commissioned. The service runs within Amazon’s proven network infrastructure and data centers.

• Secure—Amazon EC2 provides web service interfaces to configure firewall settings that control network access to and between groups of instances.

• Inexpensive—Amazon EC2 passes on to you the financial benefits of Amazon’s scale. You pay a very low rate for the compute capacity you actually consume. Compare this with the significant up-front expenditures traditionally required to purchase and maintain hardware, either in-house or hosted. This frees you from many of the complexities of capacity planning, transforms what are commonly large fixed costs into much smaller variable costs, and removes the need to over-buy "safety net" capacity to handle periodic traffic spikes.

Features for Building Failure Resilient Applications

• Amazon Elastic Block Store—Amazon Elastic Block Store (Amazon EBS) offers persistent storage for Amazon EC2 instances. Amazon EBS volumes provide off-instance storage that persists independently from the life of an instance. Amazon EBS volumes are highly available, highly reliable volumes that can be attached to a running Amazon EC2 instance and are exposed as standard block devices. Amazon EBS volumes offer greatly improved durability over local Amazon EC2 instance stores, as Amazon EBS volumes are automatically replicated on the backend (in a single Availability Zone). For those wanting even more durability, Amazon EBS provides the ability to create point-in-time consistent snapshots of your volumes that are then stored in Amazon S3, and automatically replicated across multiple Availability Zones. These snapshots can be used as the starting point for new Amazon EBS volumes, and can protect your data for long term durability.

• Regions and Availability Zones—Amazon EC2 provides the ability to place instances in different regions and Availability Zones. Regions are dispersed in separate geographic areas or countries. Availability Zones are located within regions and are engineered to be insulated from failures in other Availability Zones and provide inexpensive low latency network connectivity to other Availability Zones in the same region. By launching instances in separate Availability Zones, you can protect your applications from the failure of a single Availability Zone.

• Elastic IP Addresses—Elastic IP addresses are static IP addresses designed for dynamic cloud computing. An Elastic IP address is associated with your account not a particular instance, and you control that address until you choose to explicitly release it. Unlike traditional static IP addresses, however, Elastic IP addresses allow you to mask instance or Availability Zone failures by programmatically remapping your public IP addresses to any instance in your account. Rather than waiting on a data technician to reconfigure or replace your host, or waiting for DNS to propagate to all of your customers, Amazon EC2 enables you to engineer around problems with your instance or software by quickly remapping your Elastic IP address to a replacement instance.