UpdateAutoScalingGroup - Amazon EC2 Auto Scaling

UpdateAutoScalingGroup

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.

Request Parameters

For information about the parameters that are common to all actions, see Common Parameters.

AutoScalingGroupName

The name of the Auto Scaling group.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 255.

Pattern: [\u0020-\uD7FF\uE000-\uFFFD\uD800\uDC00-\uDBFF\uDFFF\r\n\t]*

Required: Yes

AvailabilityZones.member.N

One or more Availability Zones for the group.

Type: Array of strings

Length Constraints: Minimum length of 1. Maximum length of 255.

Pattern: [\u0020-\uD7FF\uE000-\uFFFD\uD800\uDC00-\uDBFF\uDFFF\r\n\t]*

Required: No

CapacityRebalance

Enables or disables Capacity Rebalancing. For more information, see Use Capacity Rebalancing to handle Amazon EC2 Spot Interruptions in the Amazon EC2 Auto Scaling User Guide.

Type: Boolean

Required: No

Context

Reserved.

Type: String

Required: No

DefaultCooldown

Only needed if you use simple scaling policies.

The amount of time, in seconds, between one scaling activity ending and another one starting due to simple scaling policies. For more information, see Scaling cooldowns for Amazon EC2 Auto Scaling in the Amazon EC2 Auto Scaling User Guide.

Type: Integer

Required: No

DefaultInstanceWarmup

The amount of time, in seconds, until a new instance is considered to have finished initializing and resource consumption to become stable after it enters the InService state.

During an instance refresh, Amazon EC2 Auto Scaling waits for the warm-up period after it replaces an instance before it moves on to replacing the next instance. Amazon EC2 Auto Scaling also waits for the warm-up period before aggregating the metrics for new instances with existing instances in the Amazon CloudWatch metrics that are used for scaling, resulting in more reliable usage data. For more information, see Set the default instance warmup for an Auto Scaling group in the Amazon EC2 Auto Scaling User Guide.

Important

To manage various warm-up settings at the group level, we recommend that you set the default instance warmup, even if it is set to 0 seconds. To remove a value that you previously set, include the property but specify -1 for the value. However, we strongly recommend keeping the default instance warmup enabled by specifying a value of 0 or other nominal value.

Type: Integer

Required: No

DesiredCapacity

The desired capacity is the initial capacity of the Auto Scaling group after this operation completes and the capacity it attempts to maintain. This number must be greater than or equal to the minimum size of the group and less than or equal to the maximum size of the group.

Type: Integer

Required: No

DesiredCapacityType

The unit of measurement for the value specified for desired capacity. Amazon EC2 Auto Scaling supports DesiredCapacityType for attribute-based instance type selection only. For more information, see Creating an Auto Scaling group using attribute-based instance type selection in the Amazon EC2 Auto Scaling User Guide.

By default, Amazon EC2 Auto Scaling specifies units, which translates into number of instances.

Valid values: units | vcpu | memory-mib

Type: String

Length Constraints: Minimum length of 1. Maximum length of 255.

Pattern: [\u0020-\uD7FF\uE000-\uFFFD\uD800\uDC00-\uDBFF\uDFFF\r\n\t]*

Required: No

HealthCheckGracePeriod

The amount of time, in seconds, that Amazon EC2 Auto Scaling waits before checking the health status of an EC2 instance that has come into service and marking it unhealthy due to a failed health check. This is useful if your instances do not immediately pass their health checks after they enter the InService state. For more information, see Set the health check grace period for an Auto Scaling group in the Amazon EC2 Auto Scaling User Guide.

Type: Integer

Required: No

HealthCheckType

A comma-separated value string of one or more health check types.

The valid values are EC2, ELB, and VPC_LATTICE. EC2 is the default health check and cannot be disabled. For more information, see Health checks for Auto Scaling instances in the Amazon EC2 Auto Scaling User Guide.

Only specify EC2 if you must clear a value that was previously set.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 32.

Pattern: [\u0020-\uD7FF\uE000-\uFFFD\uD800\uDC00-\uDBFF\uDFFF\r\n\t]*

Required: No

InstanceMaintenancePolicy

An instance maintenance policy. For more information, see Set instance maintenance policy in the Amazon EC2 Auto Scaling User Guide.

Type: InstanceMaintenancePolicy object

Required: No

LaunchConfigurationName

The name of the launch configuration. If you specify LaunchConfigurationName in your update request, you can't specify LaunchTemplate or MixedInstancesPolicy.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 255.

Pattern: [\u0020-\uD7FF\uE000-\uFFFD\uD800\uDC00-\uDBFF\uDFFF\r\n\t]*

Required: No

LaunchTemplate

The launch template and version to use to specify the updates. If you specify LaunchTemplate in your update request, you can't specify LaunchConfigurationName or MixedInstancesPolicy.

Type: LaunchTemplateSpecification object

Required: No

MaxInstanceLifetime

The maximum amount of time, in seconds, that an instance can be in service. The default is null. If specified, the value must be either 0 or a number equal to or greater than 86,400 seconds (1 day). To clear a previously set value, specify a new value of 0. For more information, see Replacing Auto Scaling instances based on maximum instance lifetime in the Amazon EC2 Auto Scaling User Guide.

Type: Integer

Required: No

MaxSize

The maximum size of the Auto Scaling group.

Note

With a mixed instances policy that uses instance weighting, Amazon EC2 Auto Scaling may need to go above MaxSize to meet your capacity requirements. In this event, Amazon EC2 Auto Scaling will never go above MaxSize by more than your largest instance weight (weights that define how many units each instance contributes to the desired capacity of the group).

Type: Integer

Required: No

MinSize

The minimum size of the Auto Scaling group.

Type: Integer

Required: No

MixedInstancesPolicy

The mixed instances policy. For more information, see Auto Scaling groups with multiple instance types and purchase options in the Amazon EC2 Auto Scaling User Guide.

Type: MixedInstancesPolicy object

Required: No

NewInstancesProtectedFromScaleIn

Indicates whether newly launched instances are protected from termination by Amazon EC2 Auto Scaling when scaling in. For more information about preventing instances from terminating on scale in, see Using instance scale-in protection in the Amazon EC2 Auto Scaling User Guide.

Type: Boolean

Required: No

PlacementGroup

The name of an existing placement group into which to launch your instances. For more information, see Placement groups in the Amazon EC2 User Guide for Linux Instances.

Note

A cluster placement group is a logical grouping of instances within a single Availability Zone. You cannot specify multiple Availability Zones and a cluster placement group.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 255.

Pattern: [\u0020-\uD7FF\uE000-\uFFFD\uD800\uDC00-\uDBFF\uDFFF\r\n\t]*

Required: No

ServiceLinkedRoleARN

The Amazon Resource Name (ARN) of the service-linked role that the Auto Scaling group uses to call other Amazon Web Services on your behalf. For more information, see Service-linked roles in the Amazon EC2 Auto Scaling User Guide.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 1600.

Pattern: [\u0020-\uD7FF\uE000-\uFFFD\uD800\uDC00-\uDBFF\uDFFF\r\n\t]*

Required: No

TerminationPolicies.member.N

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

Valid values: Default | AllocationStrategy | ClosestToNextInstanceHour | NewestInstance | OldestInstance | OldestLaunchConfiguration | OldestLaunchTemplate | arn:aws:lambda:region:account-id:function:my-function:my-alias

Type: Array of strings

Length Constraints: Minimum length of 1. Maximum length of 1600.

Pattern: [\u0020-\uD7FF\uE000-\uFFFD\uD800\uDC00-\uDBFF\uDFFF\r\n\t]*

Required: No

VPCZoneIdentifier

A comma-separated list of subnet IDs for a virtual private cloud (VPC). If you specify VPCZoneIdentifier with AvailabilityZones, the subnets that you specify must reside in those Availability Zones.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 2047.

Pattern: [\u0020-\uD7FF\uE000-\uFFFD\uD800\uDC00-\uDBFF\uDFFF\r\n\t]*

Required: No

Errors

For information about the errors that are common to all actions, see Common Errors.

ResourceContention

You already have a pending update to an Amazon EC2 Auto Scaling resource (for example, an Auto Scaling group, instance, or load balancer).

HTTP Status Code: 500

ScalingActivityInProgress

The operation can't be performed because there are scaling activities in progress.

HTTP Status Code: 400

ServiceLinkedRoleFailure

The service-linked role is not yet ready for use.

HTTP Status Code: 500

Examples

Example 1: Update the health check settings of an existing Auto Scaling group

This example updates the health check settings for the Auto Scaling group my-asg.

Sample Request

https://autoscaling.amazonaws.com/?Action=UpdateAutoScalingGroup &AutoScalingGroupName=my-asg &HealthCheckType=ELB &HealthCheckGracePeriod=300 &Version=2011-01-01 &AUTHPARAMS

Example 2: Update the VPC subnets of an existing Auto Scaling group

This example updates the VPC subnets for the Auto Scaling group my-asg.

Sample Request

https://autoscaling.amazonaws.com/?Action=UpdateAutoScalingGroup &AutoScalingGroupName=my-asg &VPCZoneIdentifier=subnet-057fa0918fEXAMPLE%2Csubnet-610acd08EXAMPLE%2Csubnet-530fc83aEXAMPLE &Version=2011-01-01 &AUTHPARAMS

See Also

For more information about using this API in one of the language-specific AWS SDKs, see the following: