# InstanceGroupModifyConfig
<a name="API_InstanceGroupModifyConfig"></a>

Modify the size or configurations of an instance group.

## Contents
<a name="API_InstanceGroupModifyConfig_Contents"></a>

 ** InstanceGroupId **   <a name="EMR-Type-InstanceGroupModifyConfig-InstanceGroupId"></a>
Unique ID of the instance group to modify.  
Type: String  
Length Constraints: Minimum length of 0. Maximum length of 256.  
Pattern: `[\u0020-\uD7FF\uE000-\uFFFD\uD800\uDC00-\uDBFF\uDFFF\r\n\t]*`   
Required: Yes

 ** Configurations **   <a name="EMR-Type-InstanceGroupModifyConfig-Configurations"></a>
A list of new or modified configurations to apply for an instance group.  
Type: Array of [Configuration](API_Configuration.md) objects  
Required: No

 ** EC2InstanceIdsToTerminate **   <a name="EMR-Type-InstanceGroupModifyConfig-EC2InstanceIdsToTerminate"></a>
The Amazon EC2 InstanceIds to terminate. After you terminate the instances, the instance group will not return to its original requested size.  
Type: Array of strings  
Required: No

 ** InstanceCount **   <a name="EMR-Type-InstanceGroupModifyConfig-InstanceCount"></a>
Target size for the instance group.  
Type: Integer  
Required: No

 ** ReconfigurationType **   <a name="EMR-Type-InstanceGroupModifyConfig-ReconfigurationType"></a>
Type of reconfiguration requested. Valid values are MERGE and OVERWRITE.  
Type: String  
Valid Values: `OVERWRITE | MERGE`   
Required: No

 ** ShrinkPolicy **   <a name="EMR-Type-InstanceGroupModifyConfig-ShrinkPolicy"></a>
Policy for customizing shrink operations.  
Type: [ShrinkPolicy](API_ShrinkPolicy.md) object  
Required: No

## See Also
<a name="API_InstanceGroupModifyConfig_SeeAlso"></a>

For more information about using this API in one of the language-specific AWS SDKs, see the following:
+  [AWS SDK for C\$1\$1](https://docs.aws.amazon.com/goto/SdkForCpp/elasticmapreduce-2009-03-31/InstanceGroupModifyConfig) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/elasticmapreduce-2009-03-31/InstanceGroupModifyConfig) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/elasticmapreduce-2009-03-31/InstanceGroupModifyConfig)