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 for the 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.

Console

To configure the credit specification of an instance at launch

1. Follow the procedure to launch an instance.

2. Under Instance type, select a T instance type.

3. Expand Advanced details. For Credit specification, select a credit specification.

4. 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 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 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 procedure in the Amazon EC2 Auto Scaling User Guide.

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

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

4. 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 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 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/.

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

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

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

5. 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 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/.

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

3. In the navigation pane, choose Auto Scaling Groups.

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

5. 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 command and specify the --launch-template parameter.

To add a launch template to an existing Auto Scaling group

Use the update-auto-scaling-group command and specify the --launch-template parameter.

PowerShell

To create an Auto Scaling group using a launch template

Use the New-ASAutoScalingGroup 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 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.

Console

To manage the credit specification of an instance

1. Open the Amazon EC2 console at https://console.aws.amazon.com/ec2/.

2. In the left navigation pane, choose Instances.

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

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

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

6. 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 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 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 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 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. 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/.

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

3. On the left navigation pane, choose EC2 Dashboard.

4. From Account attributes, choose Default credit specification.

5. Choose Manage.

6. 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 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 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 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 cmdlet. The following example sets the value to unlimited.

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