Amazon EC2 ImageUtilities and Get-EC2ImageByName Updates

Versions 2.3.14 of the AWS SDK for .NET and AWS Tools for Windows PowerShell, released today (December 18, 2014), contain updates to the utilities and the Get-EC2ImageByName cmdlet used to query common Microsoft Windows 64-bit Amazon Machine Images using version-independent names. Briefly, we renamed some of the keys used to identify Microsoft Windows Server 2008 images to address confusion over what versions are actually returned, and we added the ability to retrieve some additional images. In the Get-EC2ImageByName cmdlet, we made a small behavior change to help when running the cmdlet in a pipeline when more than one image version exists (as happens when Amazon periodically revises the images) – the cmdlet by default now outputs only the very latest image. The previous behavior that output all available versions (latest + prior) can be enabled using a new switch.

Renamed and New Image Keys

This change affects both the SDK Amazon.EC2.Util.ImageUtilities class and the Get-EC2ImageByName cmdlet. For some time now, the keys prefixed with Windows_2008_* have returned Microsoft Windows Server 2008 R2 images, not the original Windows Server 2008 editions, leading to some confusion. We addressed this by adding a new set of R2-specific keys—these all have the prefix Windows_2008R2_*. To maintain backward compatibility, the SDK retains the old keys, but we have tagged them with the [Obsolete] attribute and a message detailing the corresponding R2-based key you should use. Additionally, these old keys will still return Windows Server 2008 R2 images.

Note that the Get-EC2ImageByName cmdlet will not display the obsolete keys (when run with no parameters), but you can still supply them for the -Name parameter so your existing scripts will continue to function.

We also added three new keys enabling you to retrieve 64-bit Windows Server 2008 SP3 editions (base image, plus SQL Server 2008 Standard and SQL Server 2008 Express images). The keys for these images are WINDOWS_2008RTM_BASE, WINDOWS_2008RTM_SQL_SERVER_EXPRESS_2008, and WINDOWS_2008RTM_SQL_SERVER_STANDARD_2008.

The following keys are displayed when you run the cmdlet with no parameters:

PS C:> Get-EC2ImageByName
WINDOWS_2012R2_BASE
WINDOWS_2012R2_SQL_SERVER_EXPRESS_2014
WINDOWS_2012R2_SQL_SERVER_STANDARD_2014
WINDOWS_2012R2_SQL_SERVER_WEB_2014
WINDOWS_2012_BASE
WINDOWS_2012_SQL_SERVER_EXPRESS_2014
WINDOWS_2012_SQL_SERVER_STANDARD_2014
WINDOWS_2012_SQL_SERVER_WEB_2014
WINDOWS_2012_SQL_SERVER_EXPRESS_2012
WINDOWS_2012_SQL_SERVER_STANDARD_2012
WINDOWS_2012_SQL_SERVER_WEB_2012
WINDOWS_2012_SQL_SERVER_EXPRESS_2008
WINDOWS_2012_SQL_SERVER_STANDARD_2008
WINDOWS_2012_SQL_SERVER_WEB_2008
WINDOWS_2008R2_BASE
WINDOWS_2008R2_SQL_SERVER_EXPRESS_2012
WINDOWS_2008R2_SQL_SERVER_STANDARD_2012
WINDOWS_2008R2_SQL_SERVER_WEB_2012
WINDOWS_2008R2_SQL_SERVER_EXPRESS_2008
WINDOWS_2008R2_SQL_SERVER_STANDARD_2008
WINDOWS_2008R2_SQL_SERVER_WEB_2008
WINDOWS_2008RTM_BASE
WINDOWS_2008RTM_SQL_SERVER_EXPRESS_2008
WINDOWS_2008RTM_SQL_SERVER_STANDARD_2008
WINDOWS_2008_BEANSTALK_IIS75
WINDOWS_2012_BEANSTALK_IIS8
VPC_NAT

The following keys are deprecated but still recognized:

WINDOWS_2008_BASE
WINDOWS_2008_SQL_SERVER_EXPRESS_2012
WINDOWS_2008_SQL_SERVER_STANDARD_2012
WINDOWS_2008_SQL_SERVER_WEB_2012
WINDOWS_2008_SQL_SERVER_EXPRESS_2008
WINDOWS_2008_SQL_SERVER_STANDARD_2008
WINDOWS_2008_SQL_SERVER_WEB_2008

Get-EC2ImageByName Enhancements

Amazon periodically revises the set of Microsoft Windows images that Amazon makes available to customers and for a period, the Get-EC2ImageByName cmdlet could return the latest image for a key, plus one or more prior versions. For example, at the time of writing this post, running the command Get-EC2ImageByName -Name windows_2012r2_base emitted two images as output. If run in a pipeline that then proceeds to invoke the New-EC2Instance cmdlet, for example, instances of multiple images could then be started—perhaps not what was expected. To obtain and start the latest image only, you would have to either index the returned collection, which could contain one or several objects, or insert a call to Select-Object in your pipeline to extract the first item before then calling New-EC2Instance (the first item in the output from Get-EC2ImageByName is always the latest version).

With the new release, when a single key is supplied to the -Name parameter, the cmdlet emits only the single latest machine image that is available. This makes using the cmdlet in a ‘get | start’ pattern much safer and more convenient:

# guaranteed to only return one image to launch
PS C:> Get-EC2ImageByName -Name windows_2012r2_base | New-EC2Instance -InstanceType t1.micro ...

If you do need to get all versions of a given image, this is supported using the new ”-AllAvailable” switch. The following command outputs all available versions of the Windows Server 2012 R2 image, which may be one or several images:

PS C:> Get-EC2ImageByName -Name windows_2012r2_base -AllAvailable

The cmdlet can also emit all available versions when either more than one value is supplied for the -Name parameter or a custom key value is supplied, as it is assumed in these scenarios you are expecting a collection to work with:

# use of multiple keys (custom or built-in) yields all versions
PS C:> Get-EC2ImageByName -Name windows_2012r2_base,windows_2008r2_base

# use of a custom key, single or multiple, yields all versions
PS C:> Get-EC2ImageByName -Name "Windows_Server-2003*"

These updates to the Get-EC2ImageByName cmdlet were driven in part by feedback from our users. If you have an idea or suggestion for new features that would make your scripting life easier, please get in touch with us! One way is via the AWS PowerShell Scripting forum here.