AutoScalingClient

Amazon EC2 Auto Scaling

Amazon EC2 Auto Scaling is designed to automatically launch and terminate EC2 instances based on user-defined scaling policies, scheduled actions, and health checks.

Installation

NPM
npm install @aws-sdk/client-auto-scaling
Yarn
yarn add @aws-sdk/client-auto-scaling
pnpm
pnpm add @aws-sdk/client-auto-scaling

AutoScalingClient Operations

Command
Summary
AttachInstancesCommand

Attaches one or more EC2 instances to the specified Auto Scaling group.

When you attach instances, Amazon EC2 Auto Scaling increases the desired capacity of the group by the number of instances being attached. If the number of instances being attached plus the desired capacity of the group exceeds the maximum size of the group, the operation fails.

If there is a Classic Load Balancer attached to your Auto Scaling group, the instances are also registered with the load balancer. If there are target groups attached to your Auto Scaling group, the instances are also registered with the target groups.

For more information, see Detach or attach instances  in the Amazon EC2 Auto Scaling User Guide.

AttachLoadBalancerTargetGroupsCommand

This API operation is superseded by AttachTrafficSources , which can attach multiple traffic sources types. We recommend using AttachTrafficSources to simplify how you manage traffic sources. However, we continue to support AttachLoadBalancerTargetGroups. You can use both the original AttachLoadBalancerTargetGroups API operation and AttachTrafficSources on the same Auto Scaling group.

Attaches one or more target groups to the specified Auto Scaling group.

This operation is used with the following load balancer types:

  • Application Load Balancer - Operates at the application layer (layer 7) and supports HTTP and HTTPS.

  • Network Load Balancer - Operates at the transport layer (layer 4) and supports TCP, TLS, and UDP.

  • Gateway Load Balancer - Operates at the network layer (layer 3).

To describe the target groups for an Auto Scaling group, call the DescribeLoadBalancerTargetGroups  API. To detach the target group from the Auto Scaling group, call the DetachLoadBalancerTargetGroups  API.

This operation is additive and does not detach existing target groups or Classic Load Balancers from the Auto Scaling group.

For more information, see Use Elastic Load Balancing to distribute traffic across the instances in your Auto Scaling group  in the Amazon EC2 Auto Scaling User Guide.

AttachLoadBalancersCommand

This API operation is superseded by https://docs.aws.amazon.com/autoscaling/ec2/APIReference/API_AttachTrafficSources.html , which can attach multiple traffic sources types. We recommend using AttachTrafficSources to simplify how you manage traffic sources. However, we continue to support AttachLoadBalancers. You can use both the original AttachLoadBalancers API operation and AttachTrafficSources on the same Auto Scaling group.

Attaches one or more Classic Load Balancers to the specified Auto Scaling group. Amazon EC2 Auto Scaling registers the running instances with these Classic Load Balancers.

To describe the load balancers for an Auto Scaling group, call the DescribeLoadBalancers  API. To detach a load balancer from the Auto Scaling group, call the DetachLoadBalancers  API.

This operation is additive and does not detach existing Classic Load Balancers or target groups from the Auto Scaling group.

For more information, see Use Elastic Load Balancing to distribute traffic across the instances in your Auto Scaling group  in the Amazon EC2 Auto Scaling User Guide.

AttachTrafficSourcesCommand

Attaches one or more traffic sources to the specified Auto Scaling group.

You can use any of the following as traffic sources for an Auto Scaling group:

  • Application Load Balancer

  • Classic Load Balancer

  • Gateway Load Balancer

  • Network Load Balancer

  • VPC Lattice

This operation is additive and does not detach existing traffic sources from the Auto Scaling group.

After the operation completes, use the DescribeTrafficSources  API to return details about the state of the attachments between traffic sources and your Auto Scaling group. To detach a traffic source from the Auto Scaling group, call the DetachTrafficSources  API.

BatchDeleteScheduledActionCommand

Deletes one or more scheduled actions for the specified Auto Scaling group.

BatchPutScheduledUpdateGroupActionCommand

Creates or updates one or more scheduled scaling actions for an Auto Scaling group.

CancelInstanceRefreshCommand

Cancels an instance refresh or rollback that is in progress. If an instance refresh or rollback is not in progress, an ActiveInstanceRefreshNotFound error occurs.

This operation is part of the instance refresh feature  in Amazon EC2 Auto Scaling, which helps you update instances in your Auto Scaling group after you make configuration changes.

When you cancel an instance refresh, this does not roll back any changes that it made. Use the RollbackInstanceRefresh  API to roll back instead.

CompleteLifecycleActionCommand

Completes the lifecycle action for the specified token or instance with the specified result.

This step is a part of the procedure for adding a lifecycle hook to an Auto Scaling group:

  1. (Optional) Create a launch template or launch configuration with a user data script that runs while an instance is in a wait state due to a lifecycle hook.

  2. (Optional) Create a Lambda function and a rule that allows Amazon EventBridge to invoke your Lambda function when an instance is put into a wait state due to a lifecycle hook.

  3. (Optional) Create a notification target and an IAM role. The target can be either an Amazon SQS queue or an Amazon SNS topic. The role allows Amazon EC2 Auto Scaling to publish lifecycle notifications to the target.

  4. Create the lifecycle hook. Specify whether the hook is used when the instances launch or terminate.

  5. If you need more time, record the lifecycle action heartbeat to keep the instance in a wait state.

  6. If you finish before the timeout period ends, send a callback by using the CompleteLifecycleAction  API call.

For more information, see Complete a lifecycle action  in the Amazon EC2 Auto Scaling User Guide.

CreateAutoScalingGroupCommand

We strongly recommend using a launch template when calling this operation to ensure full functionality for Amazon EC2 Auto Scaling and Amazon EC2.

Creates an Auto Scaling group with the specified name and attributes.

If you exceed your maximum limit of Auto Scaling groups, the call fails. To query this limit, call the DescribeAccountLimits  API. For information about updating this limit, see Quotas for Amazon EC2 Auto Scaling  in the Amazon EC2 Auto Scaling User Guide.

If you're new to Amazon EC2 Auto Scaling, see the introductory tutorials in Get started with Amazon EC2 Auto Scaling  in the Amazon EC2 Auto Scaling User Guide.

Every Auto Scaling group has three size properties (DesiredCapacity, MaxSize, and MinSize). Usually, you set these sizes based on a specific number of instances. However, if you configure a mixed instances policy that defines weights for the instance types, you must specify these sizes with the same units that you use for weighting instances.

CreateLaunchConfigurationCommand

Creates a launch configuration.

If you exceed your maximum limit of launch configurations, the call fails. To query this limit, call the DescribeAccountLimits  API. For information about updating this limit, see Quotas for Amazon EC2 Auto Scaling  in the Amazon EC2 Auto Scaling User Guide.

For more information, see Launch configurations  in the Amazon EC2 Auto Scaling User Guide.

Amazon EC2 Auto Scaling configures instances launched as part of an Auto Scaling group using either a launch template or a launch configuration. We strongly recommend that you do not use launch configurations. They do not provide full functionality for Amazon EC2 Auto Scaling or Amazon EC2. For information about using launch templates, see Launch templates  in the Amazon EC2 Auto Scaling User Guide.

CreateOrUpdateTagsCommand

Creates or updates tags for the specified Auto Scaling group.

When you specify a tag with a key that already exists, the operation overwrites the previous tag definition, and you do not get an error message.

For more information, see Tag Auto Scaling groups and instances  in the Amazon EC2 Auto Scaling User Guide.

DeleteAutoScalingGroupCommand

Deletes the specified Auto Scaling group.

If the group has instances or scaling activities in progress, you must specify the option to force the deletion in order for it to succeed. The force delete operation will also terminate the EC2 instances. If the group has a warm pool, the force delete option also deletes the warm pool.

To remove instances from the Auto Scaling group before deleting it, call the DetachInstances  API with the list of instances and the option to decrement the desired capacity. This ensures that Amazon EC2 Auto Scaling does not launch replacement instances.

To terminate all instances before deleting the Auto Scaling group, call the UpdateAutoScalingGroup  API and set the minimum size and desired capacity of the Auto Scaling group to zero.

If the group has scaling policies, deleting the group deletes the policies, the underlying alarm actions, and any alarm that no longer has an associated action.

For more information, see Delete your Auto Scaling infrastructure  in the Amazon EC2 Auto Scaling User Guide.

DeleteLaunchConfigurationCommand

Deletes the specified launch configuration.

The launch configuration must not be attached to an Auto Scaling group. When this call completes, the launch configuration is no longer available for use.

DeleteLifecycleHookCommand

Deletes the specified lifecycle hook.

If there are any outstanding lifecycle actions, they are completed first (ABANDON for launching instances, CONTINUE for terminating instances).

DeleteNotificationConfigurationCommand

Deletes the specified notification.

DeletePolicyCommand

Deletes the specified scaling policy.

Deleting either a step scaling policy or a simple scaling policy deletes the underlying alarm action, but does not delete the alarm, even if it no longer has an associated action.

For more information, see Delete a scaling policy  in the Amazon EC2 Auto Scaling User Guide.

DeleteScheduledActionCommand

Deletes the specified scheduled action.

DeleteTagsCommand

Deletes the specified tags.

DeleteWarmPoolCommand

Deletes the warm pool for the specified Auto Scaling group.

For more information, see Warm pools for Amazon EC2 Auto Scaling  in the Amazon EC2 Auto Scaling User Guide.

DescribeAccountLimitsCommand

Describes the current Amazon EC2 Auto Scaling resource quotas for your account.

When you establish an Amazon Web Services account, the account has initial quotas on the maximum number of Auto Scaling groups and launch configurations that you can create in a given Region. For more information, see Quotas for Amazon EC2 Auto Scaling  in the Amazon EC2 Auto Scaling User Guide.

DescribeAdjustmentTypesCommand

Describes the available adjustment types for step scaling and simple scaling policies.

The following adjustment types are supported:

  • ChangeInCapacity

  • ExactCapacity

  • PercentChangeInCapacity

DescribeAutoScalingGroupsCommand

Gets information about the Auto Scaling groups in the account and Region.

If you specify Auto Scaling group names, the output includes information for only the specified Auto Scaling groups. If you specify filters, the output includes information for only those Auto Scaling groups that meet the filter criteria. If you do not specify group names or filters, the output includes information for all Auto Scaling groups.

This operation also returns information about instances in Auto Scaling groups. To retrieve information about the instances in a warm pool, you must call the DescribeWarmPool  API.

DescribeAutoScalingInstancesCommand

Gets information about the Auto Scaling instances in the account and Region.

DescribeAutoScalingNotificationTypesCommand

Describes the notification types that are supported by Amazon EC2 Auto Scaling.

DescribeInstanceRefreshesCommand

Gets information about the instance refreshes for the specified Auto Scaling group from the previous six weeks.

This operation is part of the instance refresh feature  in Amazon EC2 Auto Scaling, which helps you update instances in your Auto Scaling group after you make configuration changes.

To help you determine the status of an instance refresh, Amazon EC2 Auto Scaling returns information about the instance refreshes you previously initiated, including their status, start time, end time, the percentage of the instance refresh that is complete, and the number of instances remaining to update before the instance refresh is complete. If a rollback is initiated while an instance refresh is in progress, Amazon EC2 Auto Scaling also returns information about the rollback of the instance refresh.

DescribeLaunchConfigurationsCommand

Gets information about the launch configurations in the account and Region.

DescribeLifecycleHookTypesCommand

Describes the available types of lifecycle hooks.

The following hook types are supported:

  • autoscaling:EC2_INSTANCE_LAUNCHING

  • autoscaling:EC2_INSTANCE_TERMINATING

DescribeLifecycleHooksCommand

Gets information about the lifecycle hooks for the specified Auto Scaling group.

DescribeLoadBalancerTargetGroupsCommand

This API operation is superseded by DescribeTrafficSources , which can describe multiple traffic sources types. We recommend using DetachTrafficSources to simplify how you manage traffic sources. However, we continue to support DescribeLoadBalancerTargetGroups. You can use both the original DescribeLoadBalancerTargetGroups API operation and DescribeTrafficSources on the same Auto Scaling group.

Gets information about the Elastic Load Balancing target groups for the specified Auto Scaling group.

To determine the attachment status of the target group, use the State element in the response. When you attach a target group to an Auto Scaling group, the initial State value is Adding. The state transitions to Added after all Auto Scaling instances are registered with the target group. If Elastic Load Balancing health checks are enabled for the Auto Scaling group, the state transitions to InService after at least one Auto Scaling instance passes the health check. When the target group is in the InService state, Amazon EC2 Auto Scaling can terminate and replace any instances that are reported as unhealthy. If no registered instances pass the health checks, the target group doesn't enter the InService state.

Target groups also have an InService state if you attach them in the CreateAutoScalingGroup  API call. If your target group state is InService, but it is not working properly, check the scaling activities by calling DescribeScalingActivities  and take any corrective actions necessary.

For help with failed health checks, see Troubleshooting Amazon EC2 Auto Scaling: Health checks  in the Amazon EC2 Auto Scaling User Guide. For more information, see Use Elastic Load Balancing to distribute traffic across the instances in your Auto Scaling group  in the Amazon EC2 Auto Scaling User Guide.

You can use this operation to describe target groups that were attached by using AttachLoadBalancerTargetGroups , but not for target groups that were attached by using AttachTrafficSources .

DescribeLoadBalancersCommand

This API operation is superseded by DescribeTrafficSources , which can describe multiple traffic sources types. We recommend using DescribeTrafficSources to simplify how you manage traffic sources. However, we continue to support DescribeLoadBalancers. You can use both the original DescribeLoadBalancers API operation and DescribeTrafficSources on the same Auto Scaling group.

Gets information about the load balancers for the specified Auto Scaling group.

This operation describes only Classic Load Balancers. If you have Application Load Balancers, Network Load Balancers, or Gateway Load Balancers, use the DescribeLoadBalancerTargetGroups  API instead.

To determine the attachment status of the load balancer, use the State element in the response. When you attach a load balancer to an Auto Scaling group, the initial State value is Adding. The state transitions to Added after all Auto Scaling instances are registered with the load balancer. If Elastic Load Balancing health checks are enabled for the Auto Scaling group, the state transitions to InService after at least one Auto Scaling instance passes the health check. When the load balancer is in the InService state, Amazon EC2 Auto Scaling can terminate and replace any instances that are reported as unhealthy. If no registered instances pass the health checks, the load balancer doesn't enter the InService state.

Load balancers also have an InService state if you attach them in the CreateAutoScalingGroup  API call. If your load balancer state is InService, but it is not working properly, check the scaling activities by calling DescribeScalingActivities  and take any corrective actions necessary.

For help with failed health checks, see Troubleshooting Amazon EC2 Auto Scaling: Health checks  in the Amazon EC2 Auto Scaling User Guide. For more information, see Use Elastic Load Balancing to distribute traffic across the instances in your Auto Scaling group  in the Amazon EC2 Auto Scaling User Guide.

DescribeMetricCollectionTypesCommand

Describes the available CloudWatch metrics for Amazon EC2 Auto Scaling.

DescribeNotificationConfigurationsCommand

Gets information about the Amazon SNS notifications that are configured for one or more Auto Scaling groups.

DescribePoliciesCommand

Gets information about the scaling policies in the account and Region.

DescribeScalingActivitiesCommand

Gets information about the scaling activities in the account and Region.

When scaling events occur, you see a record of the scaling activity in the scaling activities. For more information, see Verify a scaling activity for an Auto Scaling group  in the Amazon EC2 Auto Scaling User Guide.

If the scaling event succeeds, the value of the StatusCode element in the response is Successful. If an attempt to launch instances failed, the StatusCode value is Failed or Cancelled and the StatusMessage element in the response indicates the cause of the failure. For help interpreting the StatusMessage, see Troubleshooting Amazon EC2 Auto Scaling  in the Amazon EC2 Auto Scaling User Guide.

DescribeScalingProcessTypesCommand

Describes the scaling process types for use with the ResumeProcesses  and SuspendProcesses  APIs.

DescribeScheduledActionsCommand

Gets information about the scheduled actions that haven't run or that have not reached their end time.

To describe the scaling activities for scheduled actions that have already run, call the DescribeScalingActivities  API.

DescribeTagsCommand

Describes the specified tags.

You can use filters to limit the results. For example, you can query for the tags for a specific Auto Scaling group. You can specify multiple values for a filter. A tag must match at least one of the specified values for it to be included in the results.

You can also specify multiple filters. The result includes information for a particular tag only if it matches all the filters. If there's no match, no special message is returned.

For more information, see Tag Auto Scaling groups and instances  in the Amazon EC2 Auto Scaling User Guide.

DescribeTerminationPolicyTypesCommand

Describes the termination policies supported by Amazon EC2 Auto Scaling.

For more information, see Configure termination policies for Amazon EC2 Auto Scaling  in the Amazon EC2 Auto Scaling User Guide.

DescribeTrafficSourcesCommand

Gets information about the traffic sources for the specified Auto Scaling group.

You can optionally provide a traffic source type. If you provide a traffic source type, then the results only include that traffic source type.

If you do not provide a traffic source type, then the results include all the traffic sources for the specified Auto Scaling group.

DescribeWarmPoolCommand

Gets information about a warm pool and its instances.

For more information, see Warm pools for Amazon EC2 Auto Scaling  in the Amazon EC2 Auto Scaling User Guide.

DetachInstancesCommand

Removes one or more instances from the specified Auto Scaling group.

After the instances are detached, you can manage them independent of the Auto Scaling group.

If you do not specify the option to decrement the desired capacity, Amazon EC2 Auto Scaling launches instances to replace the ones that are detached.

If there is a Classic Load Balancer attached to the Auto Scaling group, the instances are deregistered from the load balancer. If there are target groups attached to the Auto Scaling group, the instances are deregistered from the target groups.

For more information, see Detach or attach instances  in the Amazon EC2 Auto Scaling User Guide.

DetachLoadBalancerTargetGroupsCommand

This API operation is superseded by DetachTrafficSources , which can detach multiple traffic sources types. We recommend using DetachTrafficSources to simplify how you manage traffic sources. However, we continue to support DetachLoadBalancerTargetGroups. You can use both the original DetachLoadBalancerTargetGroups API operation and DetachTrafficSources on the same Auto Scaling group.

Detaches one or more target groups from the specified Auto Scaling group.

When you detach a target group, it enters the Removing state while deregistering the instances in the group. When all instances are deregistered, then you can no longer describe the target group using the DescribeLoadBalancerTargetGroups  API call. The instances remain running.

You can use this operation to detach target groups that were attached by using AttachLoadBalancerTargetGroups , but not for target groups that were attached by using AttachTrafficSources .

DetachLoadBalancersCommand

This API operation is superseded by DetachTrafficSources , which can detach multiple traffic sources types. We recommend using DetachTrafficSources to simplify how you manage traffic sources. However, we continue to support DetachLoadBalancers. You can use both the original DetachLoadBalancers API operation and DetachTrafficSources on the same Auto Scaling group.

Detaches one or more Classic Load Balancers from the specified Auto Scaling group.

This operation detaches only Classic Load Balancers. If you have Application Load Balancers, Network Load Balancers, or Gateway Load Balancers, use the DetachLoadBalancerTargetGroups  API instead.

When you detach a load balancer, it enters the Removing state while deregistering the instances in the group. When all instances are deregistered, then you can no longer describe the load balancer using the DescribeLoadBalancers  API call. The instances remain running.

DetachTrafficSourcesCommand

Detaches one or more traffic sources from the specified Auto Scaling group.

When you detach a traffic source, it enters the Removing state while deregistering the instances in the group. When all instances are deregistered, then you can no longer describe the traffic source using the DescribeTrafficSources  API call. The instances continue to run.

DisableMetricsCollectionCommand

Disables group metrics collection for the specified Auto Scaling group.

EnableMetricsCollectionCommand

Enables group metrics collection for the specified Auto Scaling group.

You can use these metrics to track changes in an Auto Scaling group and to set alarms on threshold values. You can view group metrics using the Amazon EC2 Auto Scaling console or the CloudWatch console. For more information, see Monitor CloudWatch metrics for your Auto Scaling groups and instances  in the Amazon EC2 Auto Scaling User Guide.

EnterStandbyCommand

Moves the specified instances into the standby state.

If you choose to decrement the desired capacity of the Auto Scaling group, the instances can enter standby as long as the desired capacity of the Auto Scaling group after the instances are placed into standby is equal to or greater than the minimum capacity of the group.

If you choose not to decrement the desired capacity of the Auto Scaling group, the Auto Scaling group launches new instances to replace the instances on standby.

For more information, see Temporarily removing instances from your Auto Scaling group  in the Amazon EC2 Auto Scaling User Guide.

ExecutePolicyCommand

Executes the specified policy. This can be useful for testing the design of your scaling policy.

ExitStandbyCommand

Moves the specified instances out of the standby state.

After you put the instances back in service, the desired capacity is incremented.

For more information, see Temporarily removing instances from your Auto Scaling group  in the Amazon EC2 Auto Scaling User Guide.

GetPredictiveScalingForecastCommand

Retrieves the forecast data for a predictive scaling policy.

Load forecasts are predictions of the hourly load values using historical load data from CloudWatch and an analysis of historical trends. Capacity forecasts are represented as predicted values for the minimum capacity that is needed on an hourly basis, based on the hourly load forecast.

A minimum of 24 hours of data is required to create the initial forecasts. However, having a full 14 days of historical data results in more accurate forecasts.

For more information, see Predictive scaling for Amazon EC2 Auto Scaling  in the Amazon EC2 Auto Scaling User Guide.

PutLifecycleHookCommand

Creates or updates a lifecycle hook for the specified Auto Scaling group.

Lifecycle hooks let you create solutions that are aware of events in the Auto Scaling instance lifecycle, and then perform a custom action on instances when the corresponding lifecycle event occurs.

This step is a part of the procedure for adding a lifecycle hook to an Auto Scaling group:

  1. (Optional) Create a launch template or launch configuration with a user data script that runs while an instance is in a wait state due to a lifecycle hook.

  2. (Optional) Create a Lambda function and a rule that allows Amazon EventBridge to invoke your Lambda function when an instance is put into a wait state due to a lifecycle hook.

  3. (Optional) Create a notification target and an IAM role. The target can be either an Amazon SQS queue or an Amazon SNS topic. The role allows Amazon EC2 Auto Scaling to publish lifecycle notifications to the target.

  4. Create the lifecycle hook. Specify whether the hook is used when the instances launch or terminate.

  5. If you need more time, record the lifecycle action heartbeat to keep the instance in a wait state using the RecordLifecycleActionHeartbeat  API call.

  6. If you finish before the timeout period ends, send a callback by using the CompleteLifecycleAction  API call.

For more information, see Amazon EC2 Auto Scaling lifecycle hooks  in the Amazon EC2 Auto Scaling User Guide.

If you exceed your maximum limit of lifecycle hooks, which by default is 50 per Auto Scaling group, the call fails.

You can view the lifecycle hooks for an Auto Scaling group using the DescribeLifecycleHooks  API call. If you are no longer using a lifecycle hook, you can delete it by calling the DeleteLifecycleHook  API.

PutNotificationConfigurationCommand

Configures an Auto Scaling group to send notifications when specified events take place. Subscribers to the specified topic can have messages delivered to an endpoint such as a web server or an email address.

This configuration overwrites any existing configuration.

For more information, see Amazon SNS notification options for Amazon EC2 Auto Scaling  in the Amazon EC2 Auto Scaling User Guide.

If you exceed your maximum limit of SNS topics, which is 10 per Auto Scaling group, the call fails.

PutScalingPolicyCommand

Creates or updates a scaling policy for an Auto Scaling group. Scaling policies are used to scale an Auto Scaling group based on configurable metrics. If no policies are defined, the dynamic scaling and predictive scaling features are not used.

For more information about using dynamic scaling, see Target tracking scaling policies  and Step and simple scaling policies  in the Amazon EC2 Auto Scaling User Guide.

For more information about using predictive scaling, see Predictive scaling for Amazon EC2 Auto Scaling  in the Amazon EC2 Auto Scaling User Guide.

You can view the scaling policies for an Auto Scaling group using the DescribePolicies  API call. If you are no longer using a scaling policy, you can delete it by calling the DeletePolicy  API.

PutScheduledUpdateGroupActionCommand

Creates or updates a scheduled scaling action for an Auto Scaling group.

For more information, see Scheduled scaling  in the Amazon EC2 Auto Scaling User Guide.

You can view the scheduled actions for an Auto Scaling group using the DescribeScheduledActions  API call. If you are no longer using a scheduled action, you can delete it by calling the DeleteScheduledAction  API.

If you try to schedule your action in the past, Amazon EC2 Auto Scaling returns an error message.

PutWarmPoolCommand

Creates or updates a warm pool for the specified Auto Scaling group. A warm pool is a pool of pre-initialized EC2 instances that sits alongside the Auto Scaling group. Whenever your application needs to scale out, the Auto Scaling group can draw on the warm pool to meet its new desired capacity.

This operation must be called from the Region in which the Auto Scaling group was created.

You can view the instances in the warm pool using the DescribeWarmPool  API call. If you are no longer using a warm pool, you can delete it by calling the DeleteWarmPool  API.

For more information, see Warm pools for Amazon EC2 Auto Scaling  in the Amazon EC2 Auto Scaling User Guide.

RecordLifecycleActionHeartbeatCommand

Records a heartbeat for the lifecycle action associated with the specified token or instance. This extends the timeout by the length of time defined using the PutLifecycleHook  API call.

This step is a part of the procedure for adding a lifecycle hook to an Auto Scaling group:

  1. (Optional) Create a launch template or launch configuration with a user data script that runs while an instance is in a wait state due to a lifecycle hook.

  2. (Optional) Create a Lambda function and a rule that allows Amazon EventBridge to invoke your Lambda function when an instance is put into a wait state due to a lifecycle hook.

  3. (Optional) Create a notification target and an IAM role. The target can be either an Amazon SQS queue or an Amazon SNS topic. The role allows Amazon EC2 Auto Scaling to publish lifecycle notifications to the target.

  4. Create the lifecycle hook. Specify whether the hook is used when the instances launch or terminate.

  5. If you need more time, record the lifecycle action heartbeat to keep the instance in a wait state.

  6. If you finish before the timeout period ends, send a callback by using the CompleteLifecycleAction  API call.

For more information, see Amazon EC2 Auto Scaling lifecycle hooks  in the Amazon EC2 Auto Scaling User Guide.

ResumeProcessesCommand

Resumes the specified suspended auto scaling processes, or all suspended process, for the specified Auto Scaling group.

For more information, see Suspend and resume Amazon EC2 Auto Scaling processes  in the Amazon EC2 Auto Scaling User Guide.

RollbackInstanceRefreshCommand

Cancels an instance refresh that is in progress and rolls back any changes that it made. Amazon EC2 Auto Scaling replaces any instances that were replaced during the instance refresh. This restores your Auto Scaling group to the configuration that it was using before the start of the instance refresh.

This operation is part of the instance refresh feature  in Amazon EC2 Auto Scaling, which helps you update instances in your Auto Scaling group after you make configuration changes.

A rollback is not supported in the following situations:

  • There is no desired configuration specified for the instance refresh.

  • The Auto Scaling group has a launch template that uses an Amazon Web Services Systems Manager parameter instead of an AMI ID for the ImageId property.

  • The Auto Scaling group uses the launch template's $Latest or $Default version.

When you receive a successful response from this operation, Amazon EC2 Auto Scaling immediately begins replacing instances. You can check the status of this operation through the DescribeInstanceRefreshes  API operation.

SetDesiredCapacityCommand

Sets the size of the specified Auto Scaling group.

If a scale-in activity occurs as a result of a new DesiredCapacity value that is lower than the current size of the group, the Auto Scaling group uses its termination policy to determine which instances to terminate.

For more information, see Manual scaling  in the Amazon EC2 Auto Scaling User Guide.

SetInstanceHealthCommand

Sets the health status of the specified instance.

For more information, see Set up a custom health check for your Auto Scaling group  in the Amazon EC2 Auto Scaling User Guide.

SetInstanceProtectionCommand

Updates the instance protection settings of the specified instances. This operation cannot be called on instances in a warm pool.

For more information, see Use instance scale-in protection  in the Amazon EC2 Auto Scaling User Guide.

If you exceed your maximum limit of instance IDs, which is 50 per Auto Scaling group, the call fails.

StartInstanceRefreshCommand

Starts an instance refresh.

This operation is part of the instance refresh feature  in Amazon EC2 Auto Scaling, which helps you update instances in your Auto Scaling group. This feature is helpful, for example, when you have a new AMI or a new user data script. You just need to create a new launch template that specifies the new AMI or user data script. Then start an instance refresh to immediately begin the process of updating instances in the group.

If successful, the request's response contains a unique ID that you can use to track the progress of the instance refresh. To query its status, call the DescribeInstanceRefreshes  API. To describe the instance refreshes that have already run, call the DescribeInstanceRefreshes  API. To cancel an instance refresh that is in progress, use the CancelInstanceRefresh  API.

An instance refresh might fail for several reasons, such as EC2 launch failures, misconfigured health checks, or not ignoring or allowing the termination of instances that are in Standby state or protected from scale in. You can monitor for failed EC2 launches using the scaling activities. To find the scaling activities, call the DescribeScalingActivities  API.

If you enable auto rollback, your Auto Scaling group will be rolled back automatically when the instance refresh fails. You can enable this feature before starting an instance refresh by specifying the AutoRollback property in the instance refresh preferences. Otherwise, to roll back an instance refresh before it finishes, use the RollbackInstanceRefresh  API.

SuspendProcessesCommand

Suspends the specified auto scaling processes, or all processes, for the specified Auto Scaling group.

If you suspend either the Launch or Terminate process types, it can prevent other process types from functioning properly. For more information, see Suspend and resume Amazon EC2 Auto Scaling processes  in the Amazon EC2 Auto Scaling User Guide.

To resume processes that have been suspended, call the ResumeProcesses  API.

TerminateInstanceInAutoScalingGroupCommand

Terminates the specified instance and optionally adjusts the desired group size. This operation cannot be called on instances in a warm pool.

This call simply makes a termination request. The instance is not terminated immediately. When an instance is terminated, the instance status changes to terminated. You can't connect to or start an instance after you've terminated it.

If you do not specify the option to decrement the desired capacity, Amazon EC2 Auto Scaling launches instances to replace the ones that are terminated.

By default, Amazon EC2 Auto Scaling balances instances across all Availability Zones. If you decrement the desired capacity, your Auto Scaling group can become unbalanced between Availability Zones. Amazon EC2 Auto Scaling tries to rebalance the group, and rebalancing might terminate instances in other zones. For more information, see Manual scaling  in the Amazon EC2 Auto Scaling User Guide.

UpdateAutoScalingGroupCommand

We strongly recommend that all Auto Scaling groups use launch templates to ensure full functionality for Amazon EC2 Auto Scaling and Amazon EC2.

Updates the configuration for the specified Auto Scaling group.

To update an Auto Scaling group, specify the name of the group and the property that you want to change. Any properties that you don't specify are not changed by this update request. The new settings take effect on any scaling activities after this call returns.

If you associate a new launch configuration or template with an Auto Scaling group, all new instances will get the updated configuration. Existing instances continue to run with the configuration that they were originally launched with. When you update a group to specify a mixed instances policy instead of a launch configuration or template, existing instances may be replaced to match the new purchasing options that you specified in the policy. For example, if the group currently has 100% On-Demand capacity and the policy specifies 50% Spot capacity, this means that half of your instances will be gradually terminated and relaunched as Spot Instances. When replacing instances, Amazon EC2 Auto Scaling launches new instances before terminating the old ones, so that updating your group does not compromise the performance or availability of your application.

Note the following about changing DesiredCapacity, MaxSize, or MinSize:

  • If a scale-in activity occurs as a result of a new DesiredCapacity value that is lower than the current size of the group, the Auto Scaling group uses its termination policy to determine which instances to terminate.

  • If you specify a new value for MinSize without specifying a value for DesiredCapacity, and the new MinSize is larger than the current size of the group, this sets the group's DesiredCapacity to the new MinSize value.

  • If you specify a new value for MaxSize without specifying a value for DesiredCapacity, and the new MaxSize is smaller than the current size of the group, this sets the group's DesiredCapacity to the new MaxSize value.

To see which properties have been set, call the DescribeAutoScalingGroups  API. To view the scaling policies for an Auto Scaling group, call the DescribePolicies  API. If the group has scaling policies, you can update them by calling the PutScalingPolicy  API.

AutoScalingClient Configuration

Parameter
Type
Description
defaultsMode
Optional
DefaultsMode | Provider<DefaultsMode>
The @smithy/smithy-client#DefaultsMode that will be used to determine how certain default configuration options are resolved in the SDK.
disableHostPrefix
Optional
boolean
Disable dynamically changing the endpoint of the client based on the hostPrefix trait of an operation.
extensions
Optional
RuntimeExtension[]
Optional extensions
logger
Optional
Logger
Optional logger for logging debug/info/warn/error.
maxAttempts
Optional
number | Provider<number>
Value for how many times a request will be made at most in case of retry.
profile
Optional
string
Setting a client profile is similar to setting a value for the AWS_PROFILE environment variable. Setting a profile on a client in code only affects the single client instance, unlike AWS_PROFILE.When set, and only for environments where an AWS configuration file exists, fields configurable by this file will be retrieved from the specified profile within that file. Conflicting code configuration and environment variables will still have higher priority.For client credential resolution that involves checking the AWS configuration file, the client's profile (this value) will be used unless a different profile is set in the credential provider options.
region
Optional
string | Provider<string>
The AWS region to which this client will send requests
requestHandler
Optional
__HttpHandlerUserInput
The HTTP handler to use or its constructor options. Fetch in browser and Https in Nodejs.
retryMode
Optional
string | Provider<string>
Specifies which retry algorithm to use.
useDualstackEndpoint
Optional
boolean | Provider<boolean>
Enables IPv6/IPv4 dualstack endpoint.
useFipsEndpoint
Optional
boolean | Provider<boolean>
Enables FIPS compatible endpoints.
Additional config fields are described in the full configuration type: AutoScalingClientConfig