# Configure burstable performance instances


The steps for launching, monitoring, and modifying burstable performance instances (T instances) are similar. The key difference is the default credit specification when they launch.

Each T instance family comes with the following *default credit specification*:
+ T4g, T3a, and T3 instances launch as `unlimited`
+ T3 instances on a Dedicated Host can only launch as `standard`
+ T2 instances launch as `standard`

You can [change the default credit specification](#burstable-performance-instance-set-default-credit-specification-for-account) for the account.

**Topics**
+ [

## Configure the credit specification at launch
](#launch-burstable-performance-instances)
+ [

## Configure an Auto Scaling group to set the credit specification as unlimited
](#burstable-performance-instances-auto-scaling-grp)
+ [

## Manage the credit specification of a burstable performance instance
](#modify-burstable-performance-instances)
+ [

## Manage the default credit specification for an account
](#burstable-performance-instance-set-default-credit-specification-for-account)

## Configure the credit specification at launch


You can launch your T instances with a credit specification of `unlimited` or `standard`.

The following procedures describe how to use the EC2 console or the AWS CLI. For information about using an Auto Scaling group, see [Configure an Auto Scaling group to set the credit specification as unlimited](#burstable-performance-instances-auto-scaling-grp).

------
#### [ Console ]

**To configure the credit specification of an instance at launch**

1. Follow the procedure to [launch an instance](ec2-launch-instance-wizard.md).

1. Under **Instance type**, select a T instance type.

1. Expand **Advanced details**. For **Credit specification**, select a credit specification.

1. In the **Summary** panel, review your instance configuration, and then choose **Launch instance**.

------
#### [ AWS CLI ]

**To set the credit specification of an instance at launch**  
Use the [run-instances](https://docs.aws.amazon.com/cli/latest/reference/ec2/run-instances.html) command with the `--credit-specification` option.

```
--credit-specification CpuCredits=unlimited
```

------
#### [ PowerShell ]

**To set the credit specification of an instance at launch**  
Use the [New-EC2Instance](https://docs.aws.amazon.com/powershell/latest/reference/items/New-EC2Instance.html) cmdlet with the `-CreditSpecification_CpuCredit` parameter.

```
-CreditSpecification_CpuCredit unlimited
```

------

## Configure an Auto Scaling group to set the credit specification as unlimited


When T instances are launched or started, they require CPU credits for a good bootstrapping experience. If you use an Auto Scaling group to launch your instances, we recommend that you configure your instances as `unlimited`. If you do, the instances use surplus credits when they are automatically launched or restarted by the Auto Scaling group. Using surplus credits prevents performance restrictions.

### Create a launch template


You must use a *launch template* for launching instances as `unlimited` in an Auto Scaling group. A launch configuration does not support launching instances as `unlimited`.

------
#### [ Console ]

**To create a launch template that sets the credit specification**

1. Follow the [Create a launch template using advanced settings](https://docs.aws.amazon.com/autoscaling/ec2/userguide/advanced-settings-for-your-launch-template.html) procedure in the *Amazon EC2 Auto Scaling User Guide*.

1. In **Launch template contents**, for **Instance type**, choose an instance size.

1. To launch instances as `unlimited` in an Auto Scaling group, under **Advanced details**, for **Credit specification**, choose **Unlimited**.

1. When you've finished defining the launch template parameters, choose **Create launch template**.

------
#### [ AWS CLI ]

**To create a launch template that sets the credit specification**  
Use the [create-launch-template](https://docs.aws.amazon.com/cli/latest/reference/ec2/create-launch-template.html) command.

```
aws ec2 create-launch-template \
    --launch-template-name my-launch-template \
    --version-description FirstVersion \
    --launch-template-data CreditSpecification={CpuCredits=unlimited}
```

------
#### [ PowerShell ]

**To create a launch template that sets the credit specification**  
Use the [New-EC2LaunchTemplate](https://docs.aws.amazon.com/powershell/latest/reference/items/New-EC2LaunchTemplate.html) cmdlet. Define the credit specification for the launch template data as follows.

```
$creditSpec = New-Object Amazon.EC2.Model.CreditSpecificationRequest
$creditSpec.CpuCredits = "unlimited"
$launchTemplateData = New-Object Amazon.EC2.Model.RequestLaunchTemplateData
$launchTemplateData.CreditSpecification = $creditSpec
```

------

### Associate an Auto Scaling group with a launch template


To associate the launch template with an Auto Scaling group, create the Auto Scaling group using the launch template, or add the launch template to an existing Auto Scaling group.

------
#### [ Console ]

**To create an Auto Scaling group using a launch template**

1. Open the Amazon EC2 console at [https://console.aws.amazon.com/ec2/](https://console.aws.amazon.com/ec2/).

1. On the navigation bar at the top of the screen, select the same Region that you used when you created the launch template.

1. In the navigation pane, choose **Auto Scaling Groups**, **Create Auto Scaling group**.

1. Choose **Launch Template**, select your launch template, and then choose **Next Step**.

1. Complete the fields for the Auto Scaling group. When you've finished reviewing your configuration settings on the **Review page**, choose **Create Auto Scaling group**. For more information, see [Creating an Auto Scaling Group Using a Launch Template](https://docs.aws.amazon.com/autoscaling/ec2/userguide/create-asg-launch-template.html) in the *Amazon EC2 Auto Scaling User Guide*.

**To add a launch template to an existing Auto Scaling group**

1. Open the Amazon EC2 console at [https://console.aws.amazon.com/ec2/](https://console.aws.amazon.com/ec2/).

1. On the navigation bar at the top of the screen, select the same Region that you used when you created the launch template.

1. In the navigation pane, choose **Auto Scaling Groups**.

1. From the Auto Scaling group list, select an Auto Scaling group, and choose **Actions**, **Edit**.

1. On the **Details** tab, for **Launch Template**, choose a launch template, and then choose **Save**.

------
#### [ AWS CLI ]

**To create an Auto Scaling group using a launch template**  
Use the [create-auto-scaling-group](https://docs.aws.amazon.com/cli/latest/reference/autoscaling/create-auto-scaling-group.html) command and specify the `--launch-template` parameter.

**To add a launch template to an existing Auto Scaling group**  
Use the [update-auto-scaling-group](https://docs.aws.amazon.com/cli/latest/reference/autoscaling/update-auto-scaling-group.html) command and specify the `--launch-template` parameter. 

------
#### [ PowerShell ]

**To create an Auto Scaling group using a launch template**  
Use the [New-ASAutoScalingGroup](https://docs.aws.amazon.com/powershell/latest/reference/items/New-ASAutoScalingGroup.html) cmdlet and specify the `-LaunchTemplate_LaunchTemplateId` or `-LaunchTemplate_LaunchTemplateName` parameter.

**To add a launch template to an existing Auto Scaling group**  
Use the [Update-ASAutoScalingGroup](https://docs.aws.amazon.com/powershell/latest/reference/items/Update-ASAutoScalingGroup.html) cmdlet and specify the `-LaunchTemplate_LaunchTemplateId` or `-LaunchTemplate_LaunchTemplateName` parameter.

------

## Manage the credit specification of a burstable performance instance


You can switch the credit specification of a running or stopped T instance at any time between `unlimited` and `standard`.

Note that in `unlimited` mode, an instance can spend surplus credits, which might incur an additional charge. For more information, see [Surplus credits can incur charges](burstable-performance-instances-unlimited-mode-concepts.md#unlimited-mode-surplus-credits).

------
#### [ Console ]

**To manage the credit specification of an instance**

1. Open the Amazon EC2 console at [https://console.aws.amazon.com/ec2/](https://console.aws.amazon.com/ec2/).

1. In the left navigation pane, choose **Instances**.

1. (Optional) Select an instance. On its **Details** tab, find **Credit specification**. The value is either `unlimited` or `standard`.

1. (Optional) To modify the credit specification for multiple instances at the same time, select them all.

1. Choose **Actions**, **Instance settings**, **Change credit specification**. This option is enabled only if you selected a T instance.

1. For **Unlimited mode**, select or clear the checkbox next to each instance ID.

------
#### [ AWS CLI ]

**To get the credit specification of an instance**  
Use the [describe-instance-credit-specifications](https://docs.aws.amazon.com/cli/latest/reference/ec2/describe-instance-credit-specifications.html) command. If you do not specify an instance ID, all instances with the credit specification of `unlimited` are returned. The output would also include instances that were previously configured with the `unlimited` credit specification. For example, if you resize a T3 instance to an M4 instance, while it is configured as `unlimited`, Amazon EC2 returns the M4 instance.

```
aws ec2 describe-instance-credit-specifications \
    --instance-id i-1234567890abcdef0 \
    --query InstanceCreditSpecifications[].CpuCredits \
    --output text
```

The following is example output.

```
unlimited
```

**To set the credit specification of an instance**  
Use the [modify-instance-credit-specification](https://docs.aws.amazon.com/cli/latest/reference/ec2/modify-instance-credit-specification.html) command.

```
aws ec2 modify-instance-credit-specification \
    --region us-east-1 \
    --instance-credit-specification "InstanceId=i-1234567890abcdef0,CpuCredits=unlimited"
```

------
#### [ PowerShell ]

**To get the credit specification of an instance**  
Use the [Get-EC2CreditSpecification](https://docs.aws.amazon.com/powershell/latest/reference/items/Get-EC2CreditSpecification.html) cmdlet.

```
(Get-EC2CreditSpecification `
    -InstanceId i-1234567890abcdef0).CpuCredits
```

The following is example output.

```
unlimited
```

**To set the credit specification of an instance**  
Use the [Edit-EC2InstanceCreditSpecification](https://docs.aws.amazon.com/powershell/latest/reference/items/Edit-EC2InstanceCreditSpecification.html) cmdlet.

```
Edit-EC2InstanceCreditSpecification `
    -Region us-east-1 `
    -InstanceCreditSpecification @({InstanceId="i-1234567890abcdef0" CpuCredits="unlimited"})
```

------

## Manage the default credit specification for an account


Each T instance family comes with a [default credit specification](#default-credit-spec). You can change the default credit specification for each T instance family at the account level per AWS Region. The valid values for the default credit specification are `unlimited` and `standard`.

If you use the launch instance wizard in the EC2 console to launch instances, the value you select for the credit specification overrides the account-level default credit specification. If you use the AWS CLI to launch instances, all new T instances in the account launch using the default credit specification. The credit specification for existing running or stopped instances is not affected.

**Consideration**  
The default credit specification for an instance family can be modified only once in a rolling 5-minute period, and up to four times in a rolling 24-hour period.

------
#### [ Console ]

**To manage the default credit specification**

1. Open the Amazon EC2 console at [https://console.aws.amazon.com/ec2/](https://console.aws.amazon.com/ec2/).

1. To change the AWS Region, use the Region selector in the upper-right corner of the page.

1. In the navigation pane, choose **Dashboard**.

1. On the **Account attributes** card, under **Settings**, choose **Default credit specification**.

1. Choose **Manage**.

1. For each instance family, choose **Unlimited** or **Standard**, and then choose **Update**.

------
#### [ AWS CLI ]

**To get the default credit specification**  
Use the [get-default-credit-specification](https://docs.aws.amazon.com/cli/latest/reference/ec2/get-default-credit-specification.html) command.

```
aws ec2 get-default-credit-specification \
    --region us-east-1 \
    --instance-family t2 \
    --query InstanceFamilyCreditSpecifications[].CpuCredits \
    --output text
```

The following is example output.

```
standard
```

**To set the default credit specification**  
Use the [modify-default-credit-specification](https://docs.aws.amazon.com/cli/latest/reference/ec2/modify-default-credit-specification.html) command. The following example sets the value to `unlimited`.

```
aws ec2 modify-default-credit-specification \
    --region us-east-1 \
    --instance-family t2 \
    --cpu-credits unlimited
```

------
#### [ PowerShell ]

**To get the default credit specification**  
Use the [Get-EC2DefaultCreditSpecification](https://docs.aws.amazon.com/powershell/latest/reference/items/Get-EC2DefaultCreditSpecification.html) cmdlet.

```
(Get-EC2DefaultCreditSpecification `
    -Region us-east-1 `
    -InstanceFamily t2).CpuCredits
```

The following is example output.

```
standard
```

**To set the default credit specification**  
Use the [Edit-EC2DefaultCreditSpecification](https://docs.aws.amazon.com/powershell/latest/reference/items/Edit-EC2DefaultCreditSpecification.html) cmdlet. The following example sets the value to `unlimited`.

```
Edit-EC2DefaultCreditSpecification `
    -Region us-east-1 `
    -InstanceFamily t2 `
    -CpuCredit unlimited
```

------