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Auto Scaling
API Reference (API Version 2011-01-01)

AttachInstances

Attaches one or more EC2 instances to the specified Auto Scaling group.

When you attach instances, Auto Scaling increases the desired capacity of the group by the number of instances being attached. If the number of instances being attached plus the desired capacity of the group exceeds the maximum size of the group, the operation fails.

If there is a Classic Load Balancer attached to your Auto Scaling group, the instances are also registered with the load balancer. If there are target groups attached to your Auto Scaling group, the instances are also registered with the target groups.

For more information, see Attach EC2 Instances to Your Auto Scaling Group in the Auto Scaling User Guide.

Request Parameters

For information about the parameters that are common to all actions, see Common Parameters.

AutoScalingGroupName

The name of the group.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 1600.

Pattern: [\u0020-\uD7FF\uE000-\uFFFD\uD800\uDC00-\uDBFF\uDFFF\r\n\t]*

Required: Yes

InstanceIds.member.N

One or more instance IDs.

Type: Array of strings

Length Constraints: Minimum length of 1. Maximum length of 19.

Pattern: [\u0020-\uD7FF\uE000-\uFFFD\uD800\uDC00-\uDBFF\uDFFF\r\n\t]*

Required: No

Errors

For information about the errors that are common to all actions, see Common Errors.

ResourceContention

You already have a pending update to an Auto Scaling resource (for example, a group, instance, or load balancer).

HTTP Status Code: 500

Example

Sample Request

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https://autoscaling.amazonaws.com/?Action=AttachInstances &AutoScalingGroupName=my-asg &InstanceIds.member.1=i-12345678 &Version=2011-01-01 &AUTHPARAMS

See Also

For more information about using this API in one of the language-specific AWS SDKs, see the following: