Work with burstable performance instances

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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.

Launch a burstable performance instance as Unlimited or Standard

You can launch your T instances as unlimited or standard using the Amazon EC2 console, an AWS SDK, a command line tool, or with an Auto Scaling group.

The following procedures describe how to use the EC2 console or the AWS CLI. For information about using an Auto Scaling group, see Use an Auto Scaling group to launch a burstable performance instance as Unlimited.

Console

To launch a T instance as Unlimited or Standard

1. Follow the procedure to launch an instance.

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

3. Expand Advanced details, and for Credit specification, select a credit specification. If you do not make a selection, the default is used, which is standard for T2, and unlimited for T4g, T3a, and T3.

4. In the Summary panel, review your instance configuration, and then choose Launch instance. For more information, see Launch an EC2 instance using the launch instance wizard in the console.

AWS CLI

To launch a T instance as Unlimited or Standard

Use the run-instances command to launch your instances. Specify the credit specification using the --credit-specification CpuCredits= parameter. Valid credit specifications are unlimited and standard.

• For T4g, T3a, and T3, if you do not include the --credit-specification parameter, the instance launches as unlimited by default.

• For T2, if you do not include the --credit-specification parameter, the instance launches as standard by default.

aws ec2 run-instances \
    --image-id ami-0abcdef1234567890 \
    --count 1 \
    --instance-type t3.micro \
    --key-name MyKeyPair \
    --credit-specification "CpuCredits=unlimited"

Use an Auto Scaling group to launch a burstable performance instance 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.

Note

unlimited mode is not supported for T3 instances that are launched on a Dedicated Host.

Console

To create a launch template that launches instances as Unlimited

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 launches instances as Unlimited

Use the create-launch-template command and specify unlimited as the credit specification.

• For T4g, T3a, and T3, if you do not include the CreditSpecification={CpuCredits=unlimited} value, the instance launches as unlimited by default.

• For T2, if you do not include the CreditSpecification={CpuCredits=unlimited} value, the instance launches as standard by default.

aws ec2 create-launch-template \
    --launch-template-name MyLaunchTemplate \
    --version-description FirstVersion \
    --launch-template-data ImageId=ami-8c1be5f6,InstanceType=t3.medium,CreditSpecification={CpuCredits=unlimited}

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.

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.

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.

Console

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 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 add a launch template to an existing Auto Scaling group

Use the Update-ASAutoScalingGroup cmdlet and specify the -LaunchTemplate_LaunchTemplateId or -LaunchTemplate_LaunchTemplateName parameter.

View the credit specification of a burstable performance instance

You can view the credit specification (unlimited or standard) of a running or stopped T instance.

Console

To view the credit specification of a T instance

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

2. In the left navigation pane, choose Instances.

3. Select the instance.

4. Choose Details and view the Credit specification field. The value is either unlimited or standard.

AWS CLI

To describe the credit specification of a T instance

Use the describe-instance-credit-specifications command. If you do not specify one or more instance IDs, all instances with the credit specification of unlimited are returned, as well as 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

Example output

{
  "InstanceCreditSpecifications": [
    {
        "InstanceId": "i-1234567890abcdef0",
        "CpuCredits": "unlimited"
    }
  ]
}

Modify 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 modify the credit specification of a T instance

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

2. In the left navigation pane, choose Instances.

3. Select the instance. To modify the credit specification for several instances at one time, select all applicable instances.

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

5. To change the credit specification to unlimited, select the checkbox next to the instance ID. To change the credit specification to standard, clear the checkbox next to the instance ID.

AWS CLI

To modify the credit specification of a T instance

Use the modify-instance-credit-specification command. Specify the instance and its credit specification using the --instance-credit-specification parameter. Valid credit specifications are unlimited and standard.

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

Example output

{
  "SuccessfulInstanceCreditSpecifications": [
    {
      "InstanceId": "i- 1234567890abcdef0"
    }
  ],
  "UnsuccessfulInstanceCreditSpecifications": []
}

Set the default credit specification for the 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.

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 set the default credit specification at the account level per Region

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 set the default credit specification at the account level (AWS CLI)

Use the modify-default-credit-specification command. Specify the AWS Region, instance family, and the default credit specification using the --cpu-credits parameter. Valid default credit specifications are unlimited and standard.

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

View the default credit specification

You can view the default credit specification of a T instance family at the account level per AWS Region.

Console

To view the default credit specification at the account level

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.

AWS CLI

To view the default credit specification at the account level

Use the get-default-credit-specification command. Specify the AWS Region and instance family.

aws ec2 get-default-credit-specification --region us-east-1 --instance-family t2