# ModifyDefaultCreditSpecification
<a name="API_ModifyDefaultCreditSpecification"></a>

Modifies the default credit option for CPU usage of burstable performance instances. The default credit option is set at the account level per Amazon Web Services Region, and is specified per instance family. All new burstable performance instances in the account launch using the default credit option.

 `ModifyDefaultCreditSpecification` is an asynchronous operation, which works at an Amazon Web Services Region level and modifies the credit option for each Availability Zone. All zones in a Region are updated within five minutes. But if instances are launched during this operation, they might not get the new credit option until the zone is updated. To verify whether the update has occurred, you can call `GetDefaultCreditSpecification` and check `DefaultCreditSpecification` for updates.

For more information, see [Burstable performance instances](https://docs.amazonaws.cn/AWSEC2/latest/UserGuide/burstable-performance-instances.html) in the *Amazon EC2 User Guide*.

## Request Parameters
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The following parameters are for this specific action. For more information about required and optional parameters that are common to all actions, see [Common Query Parameters](CommonParameters.md).

 **CpuCredits**   
The credit option for CPU usage of the instance family.  
Valid Values: `standard` \$1 `unlimited`   
Type: String  
Required: Yes

 **DryRun**   
Checks whether you have the required permissions for the operation, without actually making the request, and provides an error response. If you have the required permissions, the error response is `DryRunOperation`. Otherwise, it is `UnauthorizedOperation`.  
Type: Boolean  
Required: No

 **InstanceFamily**   
The instance family.  
Type: String  
Valid Values: `t2 | t3 | t3a | t4g`   
Required: Yes

## Response Elements
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The following elements are returned by the service.

 **instanceFamilyCreditSpecification**   
The default credit option for CPU usage of the instance family.  
Type: [InstanceFamilyCreditSpecification](API_InstanceFamilyCreditSpecification.md) object

 **requestId**   
The ID of the request.  
Type: String

## Errors
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For information about the errors that are common to all actions, see [Common client error codes](errors-overview.md#CommonErrors).

## Examples
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### Example 1
<a name="API_ModifyDefaultCreditSpecification_Example_1"></a>

This example modifies the default credit option for CPU usage to `unlimited` for all instances in the T2 instance family in the specified Region.

#### Sample Request
<a name="API_ModifyDefaultCreditSpecification_Example_1_Request"></a>

```
https://ec2.amazonaws.com/?Action=ModifyDefaultCreditSpecification
&Region=us-east-1
&InstanceFamily=t2
&CpuCredits=unlimited
&AUTHPARAMS
```

#### Sample Response
<a name="API_ModifyDefaultCreditSpecification_Example_1_Response"></a>

```
<ModifyDefaultCreditSpecificationResponse xmlns="http://ec2.amazonaws.com/doc/2016-11-15/">
    <requestId>11111111-2222-3333-4444-5555EXAMPLE</requestId>
    <instanceFamilyCreditSpecification>
        <cpuCredits>unlimited</cpuCredits>
        <instanceFamily>t2</instanceFamily>
    </instanceFamilyCreditSpecification>
</ModifyDefaultCreditSpecificationResponse>
```

### Example 2
<a name="API_ModifyDefaultCreditSpecification_Example_2"></a>

This example modifies the default credit option for CPU usage to `standard` for all instances in the T3 instance family in the specified Region.

#### Sample Request
<a name="API_ModifyDefaultCreditSpecification_Example_2_Request"></a>

```
https://ec2.amazonaws.com/?Action=ModifyDefaultCreditSpecification
&Region=us-east-1
&InstanceFamily=t3
&CpuCredits=standard
&AUTHPARAMS
```

#### Sample Response
<a name="API_ModifyDefaultCreditSpecification_Example_2_Response"></a>

```
<ModifyDefaultCreditSpecificationResponse xmlns="http://ec2.amazonaws.com/doc/2016-11-15/">
    <requestId>11111111-2222-3333-4444-5555EXAMPLE</requestId>
    <instanceFamilyCreditSpecification>
        <cpuCredits>standard</cpuCredits>
        <instanceFamily>t3</instanceFamily>
    </instanceFamilyCreditSpecification>
</ModifyDefaultCreditSpecificationResponse>
```

## See Also
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For more information about using this API in one of the language-specific Amazon SDKs, see the following:
+  [Amazon Command Line Interface V2](https://docs.amazonaws.cn/goto/cli2/ec2-2016-11-15/ModifyDefaultCreditSpecification) 
+  [Amazon SDK for .NET V4](https://docs.amazonaws.cn/goto/DotNetSDKV4/ec2-2016-11-15/ModifyDefaultCreditSpecification) 
+  [Amazon SDK for C\$1\$1](https://docs.amazonaws.cn/goto/SdkForCpp/ec2-2016-11-15/ModifyDefaultCreditSpecification) 
+  [Amazon SDK for Go v2](https://docs.amazonaws.cn/goto/SdkForGoV2/ec2-2016-11-15/ModifyDefaultCreditSpecification) 
+  [Amazon SDK for Java V2](https://docs.amazonaws.cn/goto/SdkForJavaV2/ec2-2016-11-15/ModifyDefaultCreditSpecification) 
+  [Amazon SDK for JavaScript V3](https://docs.amazonaws.cn/goto/SdkForJavaScriptV3/ec2-2016-11-15/ModifyDefaultCreditSpecification) 
+  [Amazon SDK for Kotlin](https://docs.amazonaws.cn/goto/SdkForKotlin/ec2-2016-11-15/ModifyDefaultCreditSpecification) 
+  [Amazon SDK for PHP V3](https://docs.amazonaws.cn/goto/SdkForPHPV3/ec2-2016-11-15/ModifyDefaultCreditSpecification) 
+  [Amazon SDK for Python](https://docs.amazonaws.cn/goto/boto3/ec2-2016-11-15/ModifyDefaultCreditSpecification) 
+  [Amazon SDK for Ruby V3](https://docs.amazonaws.cn/goto/SdkForRubyV3/ec2-2016-11-15/ModifyDefaultCreditSpecification)