Welcome - Amazon EC2 Auto Scaling
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Welcome

This is the Amazon EC2 Auto Scaling API Reference. Amazon EC2 Auto Scaling is designed to automatically launch and terminate EC2 instances based on user-defined scaling policies, scheduled actions, and health checks. This guide describes the Amazon EC2 Auto Scaling operations that you can call programmatically. For more information about Amazon EC2 Auto Scaling, see the Amazon EC2 Auto Scaling User Guide.

Note

To configure Amazon EC2 instances that are launched by your Auto Scaling group, you can specify a launch template or a launch configuration. Amazon EC2 Auto Scaling recommends that you use Amazon EC2 launch templates. Launch configurations are included as part of the same API as Auto Scaling groups, but launch templates offer more features. For more information, see Amazon EC2 Auto Scaling will no longer add support for new EC2 features to Launch Configurations on the Amazon Compute Blog.

To get started, complete the following tasks:

  1. Create a launch template using CreateLaunchTemplate.

  2. Create an Auto Scaling group using CreateAutoScalingGroup.

To make programmatic API calls, you can also use one of the Amazon SDKs, which consist of libraries and sample code for various programming languages and platforms. The SDKs provide a convenient way to create programmatic access to Amazon EC2 Auto Scaling. For example, the SDKs take care of cryptographically signing requests, managing errors, and retrying requests automatically. For information about the Amazon SDKs, including how to download and install them, see the Amazon SDKs.

API request rate

Amazon EC2 Auto Scaling uses the token bucket algorithm to implement API throttling. With this algorithm, your account has a bucket that holds a specific number of tokens. The number of tokens in the bucket represents your throttling limit at any given second. Amazon EC2 Auto Scaling throttles API requests based on a shared API bucket. For example, calls to the DescribeAutoScalingGroups and DescribeScheduledActions API operations use tokens from the same bucket. Throttling means that Amazon EC2 Auto Scaling rejects a request because the request exceeds the service's limit for the number of requests per second. When a request is throttled, Amazon EC2 Auto Scaling returns a RateExceeded error. For more information, see My Auto Scaling API calls are getting throttled. What can I do to avoid this? in the Amazon Knowledge Center.

Additional information

This document was last published on August 8, 2022.