Amazon EC2 Instances

This section provides information about instances and their basic characteristics. It also describes how to launch an instance and connect to it.

Amazon EC2 provides templates known as Amazon Machine Images (AMIs) that contains a software configuration (for example, an operating system, an application server, and applications.) You use these templates to launch an instance, which is a copy of the AMI running as a virtual server in the cloud.

You can launch different types of instances from a single AMI. An instance type essentially determines the hardware of the host computer used for your instance. Each instance type offers different compute and memory capabilities. Select an instance type based on the amount of memory and computing power that you need for the application or software that you plan to run on the instance. For more information, see Available Instance Types. You can launch multiple instances from an AMI, as shown in the following figure.

Your instance keeps running until you stop or terminate it, or until it fails. If an instance fails, you can launch a new one from the AMI.

Your AWS account has a limit on the number of instances that you can have running. For more information about these limits, and how to request an increase in your limits, see How many instances can I run in Amazon EC2 in the Amazon EC2 General FAQ.