Auto Scaling
API Reference (API Version 2011-01-01)
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Auto Scaling is a web service designed to automatically launch or terminate Amazon Elastic Compute Cloud (Amazon EC2) instances based on user-defined policies, schedules, and health checks. This service is used in conjunction with Amazon CloudWatch and Elastic Load Balancing services.

Auto Scaling provides APIs that you can call by submitting a Query Request. Query requests are HTTP or HTTPS requests that use the HTTP verbs GET or POST and a Query parameter named Action or Operation that specifies the API you are calling. Action is used throughout this documentation, although Operation is also supported for backward compatibility with other Amazon Web Services (AWS) Query APIs.

Calling the API using a Query request is the most direct way to access the web service, but requires that your application handle low-level details such as generating the hash to sign the request and error handling. The benefit of calling the service using a Query request is that you are assured of having access to the complete functionality of the API. For information about signing a a query request, see Use Query Requests to Call Auto Scaling APIs

This guide provides detailed information about Auto Scaling actions, data types, parameters, and errors. For detailed information about Auto Scaling features and their associated API actions, go to the Auto Scaling Developer Guide.

This reference is based on the current WSDL, which is available at:


The examples in this guide assume that your instances are launched in the US East (Northern Virginia) region and use us-east-1 as the endpoint.

You can set up your Auto Scaling infrastructure in other AWS regions. For information about this product's regions and endpoints, see Regions and Endpoints in the Amazon Web Services General Reference.

This document was last updated on October 9, 2014.