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Amazon Elastic Compute Cloud
User Guide for Windows Instances

Amazon Machine Images (AMI)

An Amazon Machine Image (AMI) provides the information required to launch an instance, which is a virtual server in the cloud. You must specify a source AMI when you launch an instance. You can launch multiple instances from a single AMI when you need multiple instances with the same configuration. You can use different AMIs to launch instances when you need instances with different configurations.

An AMI includes the following:

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

  • Launch permissions that control which AWS accounts can use the AMI to launch instances

  • A block device mapping that specifies the volumes to attach to the instance when it's launched

Creating Your Own AMI

You can launch an instance from an existing AMI, customize the instance, and then save this updated configuration as a custom AMI. Instances launched from this new custom AMI include the customizations that you made when you created the AMI.

For more information, see Creating a Custom Windows AMI.

To help categorize and manage your AMIs, you can assign custom tags to them. For more information, see Tagging Your Amazon EC2 Resources.

Buying, Sharing, and Selling AMIs

After you create an AMI, you can keep it private so that only you can use it, or you can share it with a specified list of AWS accounts. You can also make your custom AMI public so that the community can use it. Building a safe, secure, usable AMI for public consumption is a fairly straightforward process, if you follow a few simple guidelines. For information about how to create and use shared AMIs, see Shared AMIs.

You can purchase AMIs from a third party, including AMIs that come with service contracts from organizations such as Red Hat. You can also create an AMI and sell it to other Amazon EC2 users. For more information about buying or selling AMIs, see Paid AMIs.

Deregistering Your AMI

You can deregister an AMI when you have finished with it. After you deregister an AMI, it can't be used to launch new instances. Existing instances launched from the AMI are not affected. For more information, see Deregistering Your Windows AMI.

AWS Windows AMIs

AWS provides a set of publicly available AMIs that contain software configurations specific to the Windows platform. Using these AMIs, you can quickly start building and deploying your applications using Amazon EC2. First choose the AMI that meets your specific requirements, and then launch an instance using that AMI. You retrieve the password for the administrator account and then log in to the instance using Remote Desktop Connection, just as you would with any other Windows server.

Some Windows AMIs include an edition of Microsoft SQL Server (SQL Enterprise Edition, SQL Server Standard, SQL Server Express, or SQL Server Web). Launching an instance from a Windows AMI with Microsoft SQL Server enables you to run the instance as a database server. Alternatively, you can launch an instance from any Windows AMI and then install the database software that you need on the instance.

Microsoft no longer supports Windows Server 2003 (see Microsoft Windows Server 2003 End-of-Support). We recommend that you launch new EC2 instances using a supported version of Windows Server. If you have existing EC2 instances that are running an unsupported version of Windows Server, we recommend that you upgrade those instances to a supported version of Windows Server. For more information, see Upgrading an Amazon EC2 Windows Instance to a Newer Version of Windows Server.

Selecting an Initial Windows AMI

To view the Windows AMIs provided by AWS, you can use the Amazon EC2 console or AWS Marketplace. For more information, see Finding a Windows AMI.

You can also create an AMI from your own Windows computer. For more information, see the following services:

Keeping Your AMIs Up-to-Date

AWS provides updated, fully-patched Windows AMIs within five business days of Microsoft's patch Tuesday (the second Tuesday of each month). For more information, see Details About AWS Windows AMI Versions.

The AWS Windows AMIs contain the latest security updates available at the time they were created. For more information, see Updating Your Windows Instance.

Virtualization Types

AMIs use one of two types of virtualization: paravirtual (PV) or hardware virtual machine (HVM). The main differences between PV and HVM AMIs are the way in which they boot and whether they can take advantage of special hardware extensions for better performance. Windows AMIs are HVM AMIs.

HVM AMIs are presented with a fully virtualized set of hardware and boot by executing the master boot record of the root block device of your image. This virtualization type provides the ability to run an operating system directly on top of a virtual machine without any modification, as if it were run on the bare-metal hardware. The Amazon EC2 host system emulates some or all of the underlying hardware that is presented to the guest.

HVM guests can take advantage of hardware extensions that provide fast access to the underlying hardware on the host system. HVM AMIs are required to take advantage of enhanced networking and GPU processing. In order to pass through instructions to specialized network and GPU devices, the OS needs to be able to have access to the native hardware platform; HVM virtualization provides this access.

Paravirtual guests traditionally performed better with storage and network operations than HVM guests because they could leverage special drivers for I/O that avoided the overhead of emulating network and disk hardware, whereas HVM guests had to translate these instructions to emulated hardware. Now PV drivers are available for HVM guests, so Windows instances can get performance advantages in storage and network I/O by using them. With these PV on HVM drivers, HVM guests can get the same performance as paravirtual guests, or better.