class AutoScalingGroup (construct)

Language	Type name
.NET	`Amazon.CDK.AWS.AutoScaling.AutoScalingGroup`
Java	`software.amazon.awscdk.services.autoscaling.AutoScalingGroup`
Python	`aws_cdk.aws_autoscaling.AutoScalingGroup`
TypeScript (source)	`@aws-cdk/aws-autoscaling` » `AutoScalingGroup`

Implements IConstruct, IConstruct, IDependable, IResource, ILoadBalancerTarget, IConnectable, IApplicationLoadBalancerTarget, INetworkLoadBalancerTarget, IAutoScalingGroup, IGrantable

A Fleet represents a managed set of EC2 instances.

The Fleet models a number of AutoScalingGroups, a launch configuration, a security group and an instance role.

It allows adding arbitrary commands to the startup scripts of the instances in the fleet.

The ASG spans the availability zones specified by vpcSubnets, falling back to the Vpc default strategy if not specified.

Example

declare const vpc: ec2.Vpc;

const mySecurityGroup = new ec2.SecurityGroup(this, 'SecurityGroup', { vpc });
new autoscaling.AutoScalingGroup(this, 'ASG', {
  vpc,
  instanceType: ec2.InstanceType.of(ec2.InstanceClass.BURSTABLE2, ec2.InstanceSize.MICRO),
  machineImage: new ec2.AmazonLinuxImage(),
  securityGroup: mySecurityGroup,
});

Initializer

new AutoScalingGroup(scope: Construct, id: string, props: AutoScalingGroupProps)

Parameters

scope Construct
id string
props AutoScalingGroupProps

Construct Props

Name	Type	Description
vpc	`IVpc`	VPC to launch these instances in.
allowAllOutbound?	`boolean`	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.
autoScalingGroupName?	`string`	The name of the Auto Scaling group.
blockDevices?	`BlockDevice[]`	Specifies how block devices are exposed to the instance. You can specify virtual devices and EBS volumes.
cooldown?	`Duration`	Default scaling cooldown for this AutoScalingGroup.
desiredCapacity?	`number`	Initial amount of instances in the fleet.
groupMetrics?	`GroupMetrics[]`	Enable monitoring for group metrics, these metrics describe the group rather than any of its instances.
healthCheck?	`HealthCheck`	Configuration for health checks.
ignoreUnmodifiedSizeProperties?	`boolean`	If the ASG has scheduled actions, don't reset unchanged group sizes.
init?	`CloudFormationInit`	Apply the given CloudFormation Init configuration to the instances in the AutoScalingGroup at startup.
initOptions?	`ApplyCloudFormationInitOptions`	Use the given options for applying CloudFormation Init.
instanceMonitoring?	`Monitoring`	Controls whether instances in this group are launched with detailed or basic monitoring.
instanceType?	`InstanceType`	Type of instance to launch.
keyName?	`string`	Name of SSH keypair to grant access to instances.
launchTemplate?	`ILaunchTemplate`	Launch template to use.
machineImage?	`IMachineImage`	AMI to launch.
maxCapacity?	`number`	Maximum number of instances in the fleet.
maxInstanceLifetime?	`Duration`	The maximum amount of time that an instance can be in service.
minCapacity?	`number`	Minimum number of instances in the fleet.
mixedInstancesPolicy?	`MixedInstancesPolicy`	Mixed Instances Policy to use.
newInstancesProtectedFromScaleIn?	`boolean`	Whether newly-launched instances are protected from termination by Amazon EC2 Auto Scaling when scaling in.
notifications?	`NotificationConfiguration[]`	Configure autoscaling group to send notifications about fleet changes to an SNS topic(s).
notificationsTopic?⚠️	`ITopic`	SNS topic to send notifications about fleet changes.
replacingUpdateMinSuccessfulInstancesPercent?⚠️	`number`	Configuration for replacing updates.
requireImdsv2?	`boolean`	Whether IMDSv2 should be required on launched instances.
resourceSignalCount?⚠️	`number`	How many ResourceSignal calls CloudFormation expects before the resource is considered created.
resourceSignalTimeout?⚠️	`Duration`	The length of time to wait for the resourceSignalCount.
role?	`IRole`	An IAM role to associate with the instance profile assigned to this Auto Scaling Group.
rollingUpdateConfiguration?⚠️	`RollingUpdateConfiguration`	Configuration for rolling updates.
securityGroup?	`ISecurityGroup`	Security group to launch the instances in.
signals?	`Signals`	Configure waiting for signals during deployment.
spotPrice?	`string`	The maximum hourly price (in USD) to be paid for any Spot Instance launched to fulfill the request.
terminationPolicies?	`TerminationPolicy[]`	A policy or a list of policies that are used to select the instances to terminate.
updatePolicy?	`UpdatePolicy`	What to do when an AutoScalingGroup's instance configuration is changed.
updateType?⚠️	`UpdateType`	What to do when an AutoScalingGroup's instance configuration is changed.
userData?	`UserData`	Specific UserData to use.
vpcSubnets?	`SubnetSelection`	Where to place instances within the VPC.

vpc

Type: IVpc

VPC to launch these instances in.

allowAllOutbound?

Type: boolean (optional, default: true)

Whether the instances can initiate connections to anywhere by default.

associatePublicIpAddress?

Type: boolean (optional, default: Use subnet setting.)

Whether instances in the Auto Scaling Group should have public IP addresses associated with them.

autoScalingGroupName?

Type: string (optional, default: Auto generated by CloudFormation)

The name of the Auto Scaling group.

This name must be unique per Region per account.

blockDevices?

Type: BlockDevice[] (optional, default: Uses the block device mapping of the AMI)

Specifies how block devices are exposed to the instance. You can specify virtual devices and EBS volumes.

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.

cooldown?

Type: Duration (optional, default: Duration.minutes(5))

Default scaling cooldown for this AutoScalingGroup.

desiredCapacity?

Type: number (optional, default: minCapacity, and leave unchanged during deployment)

Initial amount of instances in the fleet.

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?

Type: GroupMetrics[] (optional, default: no group metrics will be reported)

Enable monitoring for group metrics, these metrics describe the group rather than any of its instances.

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

healthCheck?

Type: HealthCheck (optional, default: HealthCheck.ec2 with no grace period)

Configuration for health checks.

ignoreUnmodifiedSizeProperties?

Type: boolean (optional, default: 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.

init?

Type: CloudFormationInit (optional, default: no CloudFormation init)

Apply the given CloudFormation Init configuration to the instances in the AutoScalingGroup at startup.

If you specify init, you must also specify signals to configure the number of instances to wait for and the timeout for waiting for the init process.

initOptions?

Type: ApplyCloudFormationInitOptions (optional, default: default options)

Use the given options for applying CloudFormation Init.

Describes the configsets to use and the timeout to wait

instanceMonitoring?

Type: Monitoring (optional, default: 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.

instanceType?

Type: InstanceType (optional, default: Do not provide any instance type)

Type of instance to launch.

launchTemplate must not be specified when this property is specified.

keyName?

Type: string (optional, default: No SSH access will be possible.)

Name of SSH keypair to grant access to instances.

launchTemplate?

Type: ILaunchTemplate (optional, default: Do not provide any launch template)

Launch template to use.

Launch configuration related settings and MixedInstancesPolicy must not be specified when a launch template is specified.

machineImage?

Type: IMachineImage (optional, default: Do not provide any machine image)

AMI to launch.

launchTemplate must not be specified when this property is specified.

maxCapacity?

Type: number (optional, default: desiredCapacity)

Maximum number of instances in the fleet.

maxInstanceLifetime?

Type: Duration (optional, default: 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 604,800 seconds (7 days). To clear a previously set value, leave this property undefined.

minCapacity?

Type: number (optional, default: 1)

Minimum number of instances in the fleet.

mixedInstancesPolicy?

Type: MixedInstancesPolicy (optional, default: Do not provide any MixedInstancesPolicy)

Mixed Instances Policy to use.

Launch configuration related settings and Launch Template must not be specified when a MixedInstancesPolicy is specified.

newInstancesProtectedFromScaleIn?

Type: boolean (optional, default: 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?

Type: NotificationConfiguration[] (optional, default: No fleet change notifications will be sent.)

Configure autoscaling group to send notifications about fleet changes to an SNS topic(s).

notificationsTopic?⚠️

⚠️ Deprecated: use notifications

Type: ITopic (optional, default: No fleet change notifications will be sent.)

SNS topic to send notifications about fleet changes.

replacingUpdateMinSuccessfulInstancesPercent?⚠️

⚠️ Deprecated: Use signals instead

Type: number (optional, default: minSuccessfulInstancesPercent)

Configuration for replacing updates.

Only used if updateType == UpdateType.ReplacingUpdate. Specifies how many instances must signal success for the update to succeed.

requireImdsv2?

Type: boolean (optional, default: false)

Whether IMDSv2 should be required on launched instances.

resourceSignalCount?⚠️

⚠️ Deprecated: Use signals instead.

Type: number (optional, default: 1 if resourceSignalTimeout is set, 0 otherwise)

How many ResourceSignal calls CloudFormation expects before the resource is considered created.

resourceSignalTimeout?⚠️

⚠️ Deprecated: Use signals instead.

Type: Duration (optional, default: Duration.minutes(5) if resourceSignalCount is set, N/A otherwise)

The length of time to wait for the resourceSignalCount.

The maximum value is 43200 (12 hours).

role?

Type: IRole (optional, default: A role will automatically be created, it can be accessed via the role property)

An IAM role to associate with the instance profile assigned to this Auto Scaling Group.

The role must be assumable by the service principal ec2.amazonaws.com:

launchTemplate must not be specified when this property is specified. Example

   const role = new iam.Role(this, 'MyRole', {
     assumedBy: new iam.ServicePrincipal('ec2.amazonaws.com')
   });

rollingUpdateConfiguration?⚠️

⚠️ Deprecated: Use updatePolicy instead

Type: RollingUpdateConfiguration (optional, default: RollingUpdateConfiguration with defaults.)

Configuration for rolling updates.

Only used if updateType == UpdateType.RollingUpdate.

securityGroup?

Type: ISecurityGroup (optional, default: A SecurityGroup will be created if none is specified.)

Security group to launch the instances in.

launchTemplate must not be specified when this property is specified.

signals?

Type: Signals (optional, default: Do not wait for signals)

Configure waiting for signals during deployment.

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

spotPrice?

Type: string (optional, default: 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.

terminationPolicies?

Type: TerminationPolicy[] (optional, default: 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.

updatePolicy?

Type: UpdatePolicy (optional, default: UpdatePolicy.rollingUpdate() if using init, UpdatePolicy.none() otherwise)

What to do when an AutoScalingGroup's instance configuration is changed.

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.

updateType?⚠️

⚠️ Deprecated: Use updatePolicy instead

Type: UpdateType (optional, default: UpdateType.None)

What to do when an AutoScalingGroup's instance configuration is changed.

userData?

Type: UserData (optional, default: A UserData object appropriate for the MachineImage's Operating System is created.)

Specific UserData to use.

The UserData may still be mutated after creation.

launchTemplate must not be specified when this property is specified.

vpcSubnets?

Type: SubnetSelection (optional, default: All Private subnets.)

Where to place instances within the VPC.

Properties

Name	Type	Description
autoScalingGroupArn	`string`	Arn of the AutoScalingGroup.
autoScalingGroupName	`string`	Name of the AutoScalingGroup.
connections	`Connections`	The network connections associated with this resource.
env	`ResourceEnvironment`	The environment this resource belongs to.
grantPrincipal	`IPrincipal`	The principal to grant permissions to.
node	`ConstructNode`	The construct tree node associated with this construct.
osType	`OperatingSystemType`	The type of OS instances of this fleet are running.
role	`IRole`	The IAM Role in the instance profile.
stack	`Stack`	The stack in which this resource is defined.
userData	`UserData`	The Base64-encoded user data to make available to the launched EC2 instances.
albTargetGroup?	`ApplicationTargetGroup`
maxInstanceLifetime?	`Duration`	The maximum amount of time that an instance can be in service.
newInstancesProtectedFromScaleIn?	`boolean`
spotPrice?	`string`	The maximum spot price configured for the autoscaling group.

autoScalingGroupArn

Type: string

Arn of the AutoScalingGroup.

autoScalingGroupName

Type: string

Name of the AutoScalingGroup.

connections

Type: Connections

The network connections associated with this resource.

env

Type: ResourceEnvironment

The environment this resource belongs to.

For resources that are created and managed by the CDK (generally, those created by creating new class instances like Role, Bucket, etc.), this is always the same as the environment of the stack they belong to; however, for imported resources (those obtained from static methods like fromRoleArn, fromBucketName, etc.), that might be different than the stack they were imported into.

grantPrincipal

Type: IPrincipal

The principal to grant permissions to.

node

Type: ConstructNode

The construct tree node associated with this construct.

osType

Type: OperatingSystemType

The type of OS instances of this fleet are running.

role

Type: IRole

The IAM Role in the instance profile.

stack

Type: Stack

The stack in which this resource is defined.

userData

Type: UserData

The Base64-encoded user data to make available to the launched EC2 instances.

albTargetGroup?

Type: ApplicationTargetGroup (optional)

maxInstanceLifetime?

Type: Duration (optional)

The maximum amount of time that an instance can be in service.

newInstancesProtectedFromScaleIn?

Type: boolean (optional)

spotPrice?

Type: string (optional)

The maximum spot price configured for the autoscaling group.

undefined indicates that this group uses on-demand capacity.

Methods

Name	Description
addLifecycleHook(id, props)	Send a message to either an SQS queue or SNS topic when instances launch or terminate.
addSecurityGroup(securityGroup)	Add the security group to all instances via the launch configuration security groups array.
addToRolePolicy(statement)	Adds a statement to the IAM role assumed by instances of this fleet.
addUserData(...commands)	Add command to the startup script of fleet instances.
addWarmPool(options?)	Add a pool of pre-initialized EC2 instances that sits alongside an Auto Scaling group.
applyCloudFormationInit(init, options?)	Use a CloudFormation Init configuration at instance startup.
applyRemovalPolicy(policy)	Apply the given removal policy to this resource.
areNewInstancesProtectedFromScaleIn()	Returns `true` if newly-launched instances are protected from scale-in.
attachToApplicationTargetGroup(targetGroup)	Attach to ELBv2 Application Target Group.
attachToClassicLB(loadBalancer)	Attach to a classic load balancer.
attachToNetworkTargetGroup(targetGroup)	Attach to ELBv2 Application Target Group.
protectNewInstancesFromScaleIn()	Ensures newly-launched instances are protected from scale-in.
scaleOnCpuUtilization(id, props)	Scale out or in to achieve a target CPU utilization.
scaleOnIncomingBytes(id, props)	Scale out or in to achieve a target network ingress rate.
scaleOnMetric(id, props)	Scale out or in, in response to a metric.
scaleOnOutgoingBytes(id, props)	Scale out or in to achieve a target network egress rate.
scaleOnRequestCount(id, props)	Scale out or in to achieve a target request handling rate.
scaleOnSchedule(id, props)	Scale out or in based on time.
scaleToTrackMetric(id, props)	Scale out or in in order to keep a metric around a target value.
toString()	Returns a string representation of this construct.
static fromAutoScalingGroupName(scope, id, autoScalingGroupName)

addLifecycleHook(id, props)

public addLifecycleHook(id: string, props: BasicLifecycleHookProps): LifecycleHook

Parameters

id string
props BasicLifecycleHookProps

Returns

LifecycleHook

Send a message to either an SQS queue or SNS topic when instances launch or terminate.

addSecurityGroup(securityGroup)

public addSecurityGroup(securityGroup: ISecurityGroup): void

Parameters

securityGroup ISecurityGroup — : The security group to add.

Add the security group to all instances via the launch configuration security groups array.

addToRolePolicy(statement)

public addToRolePolicy(statement: PolicyStatement): void

Parameters

statement PolicyStatement

Adds a statement to the IAM role assumed by instances of this fleet.

addUserData(...commands)

public addUserData(...commands: string[]): void

Parameters

commands string

Add command to the startup script of fleet instances.

The command must be in the scripting language supported by the fleet's OS (i.e. Linux/Windows). Does nothing for imported ASGs.

addWarmPool(options?)

public addWarmPool(options?: WarmPoolOptions): WarmPool

Parameters

options WarmPoolOptions

Returns

WarmPool

Add a pool of pre-initialized EC2 instances that sits alongside an Auto Scaling group.

applyCloudFormationInit(init, options?)

public applyCloudFormationInit(init: CloudFormationInit, options?: ApplyCloudFormationInitOptions): void

Parameters

init CloudFormationInit
options ApplyCloudFormationInitOptions

Use a CloudFormation Init configuration at instance startup.

This does the following:

Attaches the CloudFormation Init metadata to the AutoScalingGroup resource.
Add commands to the UserData to run cfn-init and cfn-signal.
Update the instance's CreationPolicy to wait for cfn-init to finish before reporting success.

applyRemovalPolicy(policy)

public applyRemovalPolicy(policy: RemovalPolicy): void

Parameters

policy RemovalPolicy

Apply the given removal policy to this resource.

The Removal Policy controls what happens to this resource when it stops being managed by CloudFormation, either because you've removed it from the CDK application or because you've made a change that requires the resource to be replaced.

The resource can be deleted (RemovalPolicy.DESTROY), or left in your AWS account for data recovery and cleanup later (RemovalPolicy.RETAIN).

areNewInstancesProtectedFromScaleIn()

public areNewInstancesProtectedFromScaleIn(): boolean

Returns

boolean

Returns true if newly-launched instances are protected from scale-in.

attachToApplicationTargetGroup(targetGroup)

public attachToApplicationTargetGroup(targetGroup: IApplicationTargetGroup): LoadBalancerTargetProps

Parameters

targetGroup IApplicationTargetGroup

Returns

LoadBalancerTargetProps

Attach to ELBv2 Application Target Group.

attachToClassicLB(loadBalancer)

public attachToClassicLB(loadBalancer: LoadBalancer): void

Parameters

loadBalancer LoadBalancer

Attach to a classic load balancer.

attachToNetworkTargetGroup(targetGroup)

public attachToNetworkTargetGroup(targetGroup: INetworkTargetGroup): LoadBalancerTargetProps

Parameters

targetGroup INetworkTargetGroup

Returns

LoadBalancerTargetProps

Attach to ELBv2 Application Target Group.

protectNewInstancesFromScaleIn()

public protectNewInstancesFromScaleIn(): void

Ensures newly-launched instances are protected from scale-in.

scaleOnCpuUtilization(id, props)

public scaleOnCpuUtilization(id: string, props: CpuUtilizationScalingProps): TargetTrackingScalingPolicy

Parameters

id string
props CpuUtilizationScalingProps

Returns

TargetTrackingScalingPolicy

Scale out or in to achieve a target CPU utilization.

scaleOnIncomingBytes(id, props)

public scaleOnIncomingBytes(id: string, props: NetworkUtilizationScalingProps): TargetTrackingScalingPolicy

Parameters

id string
props NetworkUtilizationScalingProps

Returns

TargetTrackingScalingPolicy

Scale out or in to achieve a target network ingress rate.

scaleOnMetric(id, props)

public scaleOnMetric(id: string, props: BasicStepScalingPolicyProps): StepScalingPolicy

Parameters

id string
props BasicStepScalingPolicyProps

Returns

StepScalingPolicy

Scale out or in, in response to a metric.

scaleOnOutgoingBytes(id, props)

public scaleOnOutgoingBytes(id: string, props: NetworkUtilizationScalingProps): TargetTrackingScalingPolicy

Parameters

id string
props NetworkUtilizationScalingProps

Returns

TargetTrackingScalingPolicy

Scale out or in to achieve a target network egress rate.

scaleOnRequestCount(id, props)

public scaleOnRequestCount(id: string, props: RequestCountScalingProps): TargetTrackingScalingPolicy

Parameters

id string
props RequestCountScalingProps

Returns

TargetTrackingScalingPolicy

Scale out or in to achieve a target request handling rate.

The AutoScalingGroup must have been attached to an Application Load Balancer in order to be able to call this.

scaleOnSchedule(id, props)

public scaleOnSchedule(id: string, props: BasicScheduledActionProps): ScheduledAction

Parameters

id string
props BasicScheduledActionProps

Returns

ScheduledAction

Scale out or in based on time.

scaleToTrackMetric(id, props)

public scaleToTrackMetric(id: string, props: MetricTargetTrackingProps): TargetTrackingScalingPolicy

Parameters

id string
props MetricTargetTrackingProps

Returns

TargetTrackingScalingPolicy

Scale out or in in order to keep a metric around a target value.

toString()

public toString(): string

Returns

string

Returns a string representation of this construct.

static fromAutoScalingGroupName(scope, id, autoScalingGroupName)

public static fromAutoScalingGroupName(scope: Construct, id: string, autoScalingGroupName: string): IAutoScalingGroup

Parameters

scope Construct
id string
autoScalingGroupName string

Returns

IAutoScalingGroup