We have added a pair of new API functions to Auto Scaling and we have made another pair of existing functions more powerful.
DescribeAccountLimits tells you the maximum number of Launch Configurations and Auto Scaling Groups set for your account. If you need more of either one, simply fill out the EC2 Instance Request form and include the required number of each item in the Use Case field.
AttachInstances lets you attach one or more existing EC2 instances to an existing Auto Scaling group. This API can be useful if you need to warm up or manually prepare new instances for use.
The CreateLaunchConfiguration function can now use a running instance as a template for a new Launch Configuration. You can create a template that is an exact match (with the exception of the Availability Zone, which you need to set when you create the Auto Scaling group), or you can override any desired attributes.
The CreateAutoScalingGroup function now accepts an Instance ID as an optional parameter. If this parameter is supplied, the function uses the instance to create an Auto Scaling group and a Launch Configuration.
A Cool Use Case
You can use the new CreateAutoScalingGroup functionality and the new AttachInstances function to migrate an existing static system to an auto scaled version. This will allow you to upgrade without incurring any downtime or launching extraneous instances.