An IaaS architect selects one or more Amazon instance types when creating Amazon EC2 blueprints. An IaaS administrator can add or remove instance types to control the choices available to the architects.
An Amazon EC2 instance is a virtual server that can run applications in Amazon Web Services. Instances are created from an Amazon machine image and by choosing an appropriate instance type.
To provision a machine in an Amazon Web Services account, an instance type is applied to the specified Amazon machine image. The available instance types are listed when architects create the Amazon EC2 blueprint. Architects select one or more instance types, and those instance types become choices available to the user when they request to provision a machine. The instance types must be supported in the designated region.
For related information, see Selecting Instance Types and Amazon EC2 Instance Details topics in Amazon documentation.