# AddCapacityOptions

The properties for adding instance capacity to an AutoScalingGroup.

Extends: AddCapacityOptions
Extends: AddAutoScalingGroupCapacityOptions, CommonAutoScalingGroupProps

- Source: [`aws-ecs/lib/cluster.ts`](https://github.com/aws/aws-cdk/blob/v2.274.0/packages/aws-cdk-lib/aws-ecs/lib/cluster.ts#L1206)

## Example

```ts
declare const cluster: ecs.Cluster;

cluster.addCapacity('graviton-cluster', {
  minCapacity: 2,
  instanceType: new ec2.InstanceType('c6g.large'),
  machineImage: ecs.EcsOptimizedImage.amazonLinux2(ecs.AmiHardwareType.ARM),
});
```

## Properties

- `allowAllOutbound`: boolean = true — Whether the instances can initiate connections to anywhere by default.

- `associatePublicIpAddress`: boolean — Whether instances in the Auto Scaling Group should have public IP addresses associated with them.

  **Default:** Use subnet setting.

  `launchTemplate` and `mixedInstancesPolicy` must not be specified when this property is specified

- `autoScalingGroupName`: string — The name of the Auto Scaling group.

  **Default:** Auto generated by CloudFormation

  This name must be unique per Region per account.

- `azCapacityDistributionStrategy`: [CapacityDistributionStrategy](/cdk/api/v2/docs/aws-cdk-lib.aws_autoscaling.CapacityDistributionStrategy.html) = None — The strategy for distributing instances across Availability Zones.

- `blockDevices`: [BlockDevice](/cdk/api/v2/docs/aws-cdk-lib.aws_autoscaling.BlockDevice.html)[] — Specifies how block devices are exposed to the instance. You can specify virtual devices and EBS volumes.

  **Default:** Uses the block device mapping of the AMI

  Each instance that is launched has an associated root device volume,
  either an Amazon EBS volume or an instance store volume.
  You can use block device mappings to specify additional EBS volumes or
  instance store volumes to attach to an instance when it is launched.

  `launchTemplate` and `mixedInstancesPolicy` must not be specified when this property is specified

- `capacityRebalance`: boolean = false — Indicates whether Capacity Rebalancing is enabled.

  When you turn on Capacity Rebalancing, Amazon EC2 Auto Scaling
  attempts to launch a Spot Instance whenever Amazon EC2 notifies that a Spot Instance is at an elevated risk of
  interruption. After launching a new instance, it then terminates an old instance.

- `cooldown`: [Duration](/cdk/api/v2/docs/aws-cdk-lib.Duration.html) = Duration.minutes(5) — Default scaling cooldown for this AutoScalingGroup.

- `defaultInstanceWarmup`: [Duration](/cdk/api/v2/docs/aws-cdk-lib.Duration.html) = None — The amount of time, in seconds, until a newly launched instance can contribute to the Amazon CloudWatch metrics.

  This delay lets an instance finish initializing before Amazon EC2 Auto Scaling aggregates instance metrics,
  resulting in more reliable usage data. Set this value equal to the amount of time that it takes for resource
  consumption to become stable after an instance reaches the InService state.

  To optimize the performance of scaling policies that scale continuously, such as target tracking and
  step scaling policies, we strongly recommend that you enable the default instance warmup, even if its value is set to 0 seconds

  Default instance warmup will not be added if no value is specified

- `deletionProtection`: [DeletionProtection](/cdk/api/v2/docs/aws-cdk-lib.aws_autoscaling.DeletionProtection.html) = DeletionProtection.NONE — Deletion protection for the Auto Scaling group.

- `desiredCapacity`: number — Initial amount of instances in the fleet.

  **Default:** minCapacity, and leave unchanged during deployment

  If this is set to a number, every deployment will reset the amount of
  instances to this number. It is recommended to leave this value blank.

- `groupMetrics`: [GroupMetrics](/cdk/api/v2/docs/aws-cdk-lib.aws_autoscaling.GroupMetrics.html)[] — Enable monitoring for group metrics, these metrics describe the group rather than any of its instances.

  **Default:** no group metrics will be reported

  To report all group metrics use `GroupMetrics.all()`
  Group metrics are reported in a granularity of 1 minute at no additional charge.

- `healthCheck`: [HealthCheck](/cdk/api/v2/docs/aws-cdk-lib.aws_autoscaling.HealthCheck.html) — Use `healthChecks` instead

  **Default:** HealthCheck.ec2 with no grace period

- `healthChecks`: [HealthChecks](/cdk/api/v2/docs/aws-cdk-lib.aws_autoscaling.HealthChecks.html) — Configuration for EC2 or additional health checks.

  **Default:** EC2 type with no grace period

  Even when using `HealthChecks.withAdditionalChecks()`, the EC2 type is implicitly included.

- `ignoreUnmodifiedSizeProperties`: boolean = true — If the ASG has scheduled actions, don't reset unchanged group sizes.

  Only used if the ASG has scheduled actions (which may scale your ASG up
  or down regardless of cdk deployments). If true, the size of the group
  will only be reset if it has been changed in the CDK app. If false, the
  sizes will always be changed back to what they were in the CDK app
  on deployment.

- `instanceLifecyclePolicy`: [InstanceLifecyclePolicy](/cdk/api/v2/docs/aws-cdk-lib.aws_autoscaling.InstanceLifecyclePolicy.html) = None — An instance lifecycle policy that defines how instances should be handled during lifecycle events, particularly when lifecycle hooks are abandoned or fail.

- `instanceMonitoring`: [Monitoring](/cdk/api/v2/docs/aws-cdk-lib.aws_autoscaling.Monitoring.html) = Monitoring.DETAILED — Controls whether instances in this group are launched with detailed or basic monitoring.

  When detailed monitoring is enabled, Amazon CloudWatch generates metrics every minute and your account
  is charged a fee. When you disable detailed monitoring, CloudWatch generates metrics every 5 minutes.

  `launchTemplate` and `mixedInstancesPolicy` must not be specified when this property is specified

- `instanceType`: [InstanceType](/cdk/api/v2/docs/aws-cdk-lib.aws_ec2.InstanceType.html) (required) — The EC2 instance type to use when launching instances into the AutoScalingGroup.

- `keyName`: string — - Use `keyPair` instead - https://docs.aws.amazon.com/cdk/api/v2/docs/aws-cdk-lib.aws_ec2-readme.html#using-an-existing-ec2-key-pair

  **Default:** No SSH access will be possible.

  `launchTemplate` and `mixedInstancesPolicy` must not be specified when this property is specified

  You can either specify `keyPair` or `keyName`, not both.

- `keyPair`: [IKeyPair](/cdk/api/v2/docs/aws-cdk-lib.aws_ec2.IKeyPair.html) — The SSH keypair to grant access to the instance.

  **Default:** No SSH access will be possible.

  Feature flag `AUTOSCALING_GENERATE_LAUNCH_TEMPLATE` must be enabled to use this property.

  `launchTemplate` and `mixedInstancesPolicy` must not be specified when this property is specified.

  You can either specify `keyPair` or `keyName`, not both.

- `machineImage`: [IMachineImage](/cdk/api/v2/docs/aws-cdk-lib.aws_ec2.IMachineImage.html) — The ECS-optimized AMI variant to use.

  **Default:** Automatically updated, ECS-optimized Amazon Linux 2

  The default is to use an ECS-optimized AMI of Amazon Linux 2 which is
  automatically updated to the latest version on every deployment. This will
  replace the instances in the AutoScalingGroup. Make sure you have not disabled
  task draining, to avoid downtime when the AMI updates.

  To use an image that does not update on every deployment, pass:

  ```ts
  const machineImage = ecs.EcsOptimizedImage.amazonLinux2(ecs.AmiHardwareType.STANDARD, {
    cachedInContext: true,
  });
  ```

  For more information, see [Amazon ECS-optimized
  AMIs](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/ecs-optimized_AMI.html).

  You must define either `machineImage` or `machineImageType`, not both.

- `machineImageType`: [MachineImageType](/cdk/api/v2/docs/aws-cdk-lib.aws_ecs.MachineImageType.html) — What type of machine image this is.

  **Default:** Automatically determined from `machineImage`, if available, otherwise `MachineImageType.AMAZON_LINUX_2`.

  Depending on the setting, different UserData will automatically be added
  to the `AutoScalingGroup` to configure it properly for use with ECS.

  If you create an `AutoScalingGroup` yourself and are adding it via
  `addAutoScalingGroup()`, you must specify this value. If you are adding an
  `autoScalingGroup` via `addCapacity`, this value will be determined
  from the `machineImage` you pass.

- `maxCapacity`: number = desiredCapacity — Maximum number of instances in the fleet.

- `maxInstanceLifetime`: [Duration](/cdk/api/v2/docs/aws-cdk-lib.Duration.html) = none — The maximum amount of time that an instance can be in service.

  The maximum duration applies
  to all current and future instances in the group. As an instance approaches its maximum duration,
  it is terminated and replaced, and cannot be used again.

  You must specify a value of at least 86,400 seconds (one day). To clear a previously set value,
  leave this property undefined.

- `minCapacity`: number = 1 — Minimum number of instances in the fleet.

- `newInstancesProtectedFromScaleIn`: boolean = false — Whether newly-launched instances are protected from termination by Amazon EC2 Auto Scaling when scaling in.

  By default, Auto Scaling can terminate an instance at any time after launch
  when scaling in an Auto Scaling Group, subject to the group's termination
  policy. However, you may wish to protect newly-launched instances from
  being scaled in if they are going to run critical applications that should
  not be prematurely terminated.

  This flag must be enabled if the Auto Scaling Group will be associated with
  an ECS Capacity Provider with managed termination protection.

- `notifications`: [NotificationConfiguration](/cdk/api/v2/docs/aws-cdk-lib.aws_autoscaling.NotificationConfiguration.html)[] — Configure autoscaling group to send notifications about fleet changes to an SNS topic(s).

  **Default:** No fleet change notifications will be sent.

- `signals`: [Signals](/cdk/api/v2/docs/aws-cdk-lib.aws_autoscaling.Signals.html) — Configure waiting for signals during deployment.

  **Default:** Do not wait for signals

  Use this to pause the CloudFormation deployment to wait for the instances
  in the AutoScalingGroup to report successful startup during
  creation and updates. The UserData script needs to invoke `cfn-signal`
  with a success or failure code after it is done setting up the instance.

  Without waiting for signals, the CloudFormation deployment will proceed as
  soon as the AutoScalingGroup has been created or updated but before the
  instances in the group have been started.

  For example, to have instances wait for an Elastic Load Balancing health check before
  they signal success, add a health-check verification by using the
  cfn-init helper script. For an example, see the verify_instance_health
  command in the Auto Scaling rolling updates sample template:

  https://github.com/awslabs/aws-cloudformation-templates/blob/master/aws/services/AutoScaling/AutoScalingRollingUpdates.yaml

- `spotInstanceDraining`: boolean = false — Specify whether to enable Automated Draining for Spot Instances running Amazon ECS Services.

  For more information, see [Using Spot Instances](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/container-instance-spot.html).

- `spotPrice`: string = none — The maximum hourly price (in USD) to be paid for any Spot Instance launched to fulfill the request.

  Spot Instances are
  launched when the price you specify exceeds the current Spot market price.

  `launchTemplate` and `mixedInstancesPolicy` must not be specified when this property is specified

- `ssmSessionPermissions`: boolean = false — Add SSM session permissions to the instance role.

  Setting this to `true` adds the necessary permissions to connect
  to the instance using SSM Session Manager. You can do this
  from the AWS Console.

  NOTE: Setting this flag to `true` may not be enough by itself.
  You must also use an AMI that comes with the SSM Agent, or install
  the SSM Agent yourself. See
  [Working with SSM Agent](https://docs.aws.amazon.com/systems-manager/latest/userguide/ssm-agent.html)
  in the SSM Developer Guide.

- `terminationPolicies`: [TerminationPolicy](/cdk/api/v2/docs/aws-cdk-lib.aws_autoscaling.TerminationPolicy.html)[] = `TerminationPolicy.DEFAULT` — A policy or a list of policies that are used to select the instances to terminate.

  The policies are executed in the order that you list them.

- `terminationPolicyCustomLambdaFunctionArn`: string — A lambda function Arn that can be used as a custom termination policy to select the instances to terminate.

  **Default:** No lambda function Arn will be supplied

  This property must be specified if the TerminationPolicy.CUSTOM_LAMBDA_FUNCTION
  is used.

- `topicEncryptionKey`: [IKey](/cdk/api/v2/docs/aws-cdk-lib.aws_kms.IKey.html) — If `AddAutoScalingGroupCapacityOptions.taskDrainTime` is non-zero, then the ECS cluster creates an SNS Topic to as part of a system to drain instances of tasks when the instance is being shut down. If this property is provided, then this key will be used to encrypt the contents of that SNS Topic. See [SNS Data Encryption](https://docs.aws.amazon.com/sns/latest/dg/sns-data-encryption.html) for more information.

  **Default:** The SNS Topic will not be encrypted.

- `updatePolicy`: [UpdatePolicy](/cdk/api/v2/docs/aws-cdk-lib.aws_autoscaling.UpdatePolicy.html) — What to do when an AutoScalingGroup's instance configuration is changed.

  **Default:** `UpdatePolicy.rollingUpdate()` if using `init`, `UpdatePolicy.none()` otherwise

  This is applied when any of the settings on the ASG are changed that
  affect how the instances should be created (VPC, instance type, startup
  scripts, etc.). It indicates how the existing instances should be
  replaced with new instances matching the new config. By default, nothing
  is done and only new instances are launched with the new config.

- `vpcSubnets`: [SubnetSelection](/cdk/api/v2/docs/aws-cdk-lib.aws_ec2.SubnetSelection.html) — Where to place instances within the VPC.

  **Default:** All Private subnets.