AWS::AutoScaling::LaunchConfiguration - AWS CloudFormation

AWS::AutoScaling::LaunchConfiguration

The AWS::AutoScaling::LaunchConfiguration resource specifies the launch configuration that can be used by an Auto Scaling group to configure Amazon EC2 instances.

When you update the launch configuration for an Auto Scaling group, CloudFormation deletes that resource and creates a new launch configuration with the updated properties and a new name. Existing instances are not affected. To update existing instances when you update the AWS::AutoScaling::LaunchConfiguration resource, you can specify an UpdatePolicy attribute for the group. You can find sample update policies for rolling updates in Auto scaling template snippets.

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

Note

To configure Amazon EC2 instances launched as part of the Auto Scaling group, you can specify a launch template or a launch configuration. We recommend that you use a launch template to make sure that you can use the latest features of Amazon EC2, such as Dedicated Hosts and T2 Unlimited instances. For more information, see Creating a launch template for an Auto Scaling group.

Syntax

To declare this entity in your AWS CloudFormation template, use the following syntax:

JSON

{ "Type" : "AWS::AutoScaling::LaunchConfiguration", "Properties" : { "AssociatePublicIpAddress" : Boolean, "BlockDeviceMappings" : [ BlockDeviceMapping, ... ], "ClassicLinkVPCId" : String, "ClassicLinkVPCSecurityGroups" : [ String, ... ], "EbsOptimized" : Boolean, "IamInstanceProfile" : String, "ImageId" : String, "InstanceId" : String, "InstanceMonitoring" : Boolean, "InstanceType" : String, "KernelId" : String, "KeyName" : String, "LaunchConfigurationName" : String, "MetadataOptions" : MetadataOptions, "PlacementTenancy" : String, "RamDiskId" : String, "SecurityGroups" : [ String, ... ], "SpotPrice" : String, "UserData" : String } }

YAML

Type: AWS::AutoScaling::LaunchConfiguration Properties: AssociatePublicIpAddress: Boolean BlockDeviceMappings: - BlockDeviceMapping ClassicLinkVPCId: String ClassicLinkVPCSecurityGroups: - String EbsOptimized: Boolean IamInstanceProfile: String ImageId: String InstanceId: String InstanceMonitoring: Boolean InstanceType: String KernelId: String KeyName: String LaunchConfigurationName: String MetadataOptions: MetadataOptions PlacementTenancy: String RamDiskId: String SecurityGroups: - String SpotPrice: String UserData: String

Properties

AssociatePublicIpAddress

For Auto Scaling groups that are running in a virtual private cloud (VPC), specifies whether to assign a public IP address to the group's instances. If you specify true, each instance in the Auto Scaling group receives a unique public IP address. For more information, see Launching Auto Scaling instances in a VPC in the Amazon EC2 Auto Scaling User Guide.

If an instance receives a public IP address and is also in a VPC that is defined in the same stack template, you must use the DependsOn attribute to declare a dependency on the VPC-gateway attachment.

Note

If the instance is launched into a default subnet, the default is to assign a public IP address, unless you disabled the option to assign a public IP address on the subnet. If the instance is launched into a nondefault subnet, the default is not to assign a public IP address, unless you enabled the option to assign a public IP address on the subnet.

Required: No

Type: Boolean

Update requires: Replacement

BlockDeviceMappings

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

Required: No

Type: List of BlockDeviceMapping

Update requires: Replacement

ClassicLinkVPCId

The ID of a ClassicLink-enabled VPC to link your EC2-Classic instances to.

For more information, see ClassicLink in the Amazon EC2 User Guide for Linux Instances and Linking EC2-Classic instances to a VPC in the Amazon EC2 Auto Scaling User Guide.

This property can only be used if you are launching EC2-Classic instances.

Required: No

Type: String

Update requires: Replacement

ClassicLinkVPCSecurityGroups

The IDs of one or more security groups for the VPC that you specified in the ClassicLinkVPCId property.

If you specify the ClassicLinkVPCId property, you must specify this property.

Required: Conditional

Type: List of String

Update requires: Replacement

EbsOptimized

Specifies whether the launch configuration is optimized for EBS I/O (true) or not (false). This optimization provides dedicated throughput to Amazon EBS and an optimized configuration stack to provide optimal EBS I/O performance. Additional fees are incurred when you enable EBS optimization for an instance type that is not EBS-optimized by default. For more information, see Amazon EBS–optimized instances in the Amazon EC2 User Guide for Linux Instances.

The default value is false.

Required: No

Type: Boolean

Update requires: Replacement

IamInstanceProfile

Provides the name or the Amazon Resource Name (ARN) of the instance profile associated with the IAM role for the instance. The instance profile contains the IAM role.

For more information, see IAM role for applications that run on Amazon EC2 instances in the Amazon EC2 Auto Scaling User Guide.

Required: No

Type: String

Update requires: Replacement

ImageId

Provides the unique ID of the Amazon Machine Image (AMI) that was assigned during registration. For more information, see Finding a Linux AMI in the Amazon EC2 User Guide for Linux Instances.

Required: Yes

Type: String

Update requires: Replacement

InstanceId

The ID of the Amazon EC2 instance you want to use to create the launch configuration. Use this property if you want the launch configuration to use settings from an existing Amazon EC2 instance. When you use an instance to create a launch configuration, all properties are derived from the instance with the exception of BlockDeviceMapping and AssociatePublicIpAddress. You can override any properties from the instance by specifying them in the launch configuration.

Required: No

Type: String

Update requires: Replacement

InstanceMonitoring

Controls whether instances in this group are launched with detailed (true) or basic (false) monitoring. The default value is true (enabled).

Important

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

Required: No

Type: Boolean

Update requires: Replacement

InstanceType

Specifies the instance type of the EC2 instance. For information about available instance types, see Available instance types in the Amazon EC2 User Guide for Linux Instances.

Required: Yes

Type: String

Update requires: Replacement

KernelId

Provides the ID of the kernel associated with the EC2 AMI.

Note

We recommend that you use PV-GRUB instead of kernels and RAM disks. For more information, see User provided kernels in the Amazon EC2 User Guide for Linux Instances.

Required: No

Type: String

Update requires: Replacement

KeyName

Provides the name of the EC2 key pair.

Important

If you do not specify a key pair, you can't connect to the instance unless you choose an AMI that is configured to allow users another way to log in. For information on creating a key pair, see Amazon EC2 key pairs and Linux instances in the Amazon EC2 User Guide for Linux Instances.

Required: No

Type: String

Update requires: Replacement

LaunchConfigurationName

The name of the launch configuration. This name must be unique per Region per account.

Required: No

Type: String

Minimum: 1

Maximum: 255

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

Update requires: Replacement

MetadataOptions

The metadata options for the instances. For more information, see Configuring the Instance Metadata Options in the Amazon EC2 Auto Scaling User Guide.

Required: No

Type: MetadataOptions

Update requires: Replacement

PlacementTenancy

The tenancy of the instance, either default or dedicated. An instance with dedicated tenancy runs on isolated, single-tenant hardware and can only be launched into a VPC. You must set the value of this property to dedicated if want to launch dedicated instances in a shared tenancy VPC (a VPC with the instance placement tenancy attribute set to default).

If you specify this property, you must specify at least one subnet in the VPCZoneIdentifier property of the AWS::AutoScaling::AutoScalingGroup resource.

For more information, see Configuring instance tenancy with Amazon EC2 Auto Scaling in the Amazon EC2 Auto Scaling User Guide.

Required: No

Type: String

Update requires: Replacement

RamDiskId

The ID of the RAM disk to select.

Note

We recommend that you use PV-GRUB instead of kernels and RAM disks. For more information, see User provided kernels in the Amazon EC2 User Guide for Linux Instances.

Required: No

Type: String

Update requires: Replacement

SecurityGroups

A list that contains the security groups to assign to the instances in the Auto Scaling group. The list can contain both the IDs of existing security groups and references to SecurityGroup resources created in the template.

For more information, see Security groups for your VPC in the Amazon Virtual Private Cloud User Guide.

Required: No

Type: List of String

Update requires: Replacement

SpotPrice

The maximum hourly price you are willing to pay for any Spot Instances launched to fulfill the request. Spot Instances are launched when the price you specify exceeds the current Spot price. For more information, see Requesting Spot Instances for fault-tolerant and flexible applications in the Amazon EC2 Auto Scaling User Guide.

Note

When you change your maximum price by creating a new launch configuration, running instances will continue to run as long as the maximum price for those running instances is higher than the current Spot price.

Valid Range: Minimum value of 0.001

Required: No

Type: String

Update requires: Replacement

UserData

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

For more information, see Instance metadata and user data in the Amazon EC2 User Guide for Linux Instances.

Required: No

Type: String

Maximum: 21847

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

Update requires: Replacement

Return values

Ref

When the logical ID of this resource is provided to the Ref intrinsic function, Ref returns the resource name. For example: mystack-mylaunchconfig-1DDYF1E3B3I.

For more information about using the Ref function, see Ref.

Remarks

CloudFormation marks the Auto Scaling group as successful (by setting its status to CREATE_COMPLETE) when its desired capacity is reached. However, if SpotPrice is set in the launch configuration, then desired capacity is not used as a criteria for success. Whether your request is fulfilled depends on Spot Instance capacity and your maximum price. If the current Spot price is less than your specified maximum price, Amazon EC2 Auto Scaling uses the desired capacity as the target capacity for the group. If the request for Spot Instances is unsuccessful, it keeps trying.

You cannot define a duration for the Spot Instances as you can with a Spot Fleet.

Examples

The following examples create launch configurations that can be used by an Auto Scaling group to configure Amazon EC2 instances.

For more template snippets, see Auto scaling template snippets.

Amazon EBS-backed AMI and defined block device mappings

This example shows a launch configuration with a BlockDeviceMappings property that lists two devices: a 30 gigabyte EBS root volume mapped to /dev/sda1 and a 100 gigabyte EBS volume mapped to /dev/sdm. The /dev/sdm volume uses the default EBS volume type based on the region and is not deleted when terminating the instance it is attached to.

CloudFormation supports parameters from the AWS Systems Manager Parameter Store. In this example, the ImageId property of the AWS::AutoScaling::LaunchConfiguration references the latest Amazon Linux 2 AMI (EBS-backed image) from the Parameter Store. For more information, see AWS Systems Manager Parameter Store in the AWS Systems Manager User Guide and the blog post Query for the latest Amazon Linux AMI IDs using AWS Systems Manager Parameter Store on the AWS Compute Blog.

JSON

{ "AWSTemplateFormatVersion": "2010-09-09", "Parameters": { "LatestAmiId": { "Description": "Region specific image from the Parameter Store", "Type": "AWS::SSM::Parameter::Value<AWS::EC2::Image::Id>", "Default": "/aws/service/ami-amazon-linux-latest/amzn2-ami-hvm-x86_64-gp2" }, "InstanceType": { "Description": "Amazon EC2 instance type for the instances", "Type": "String", "AllowedValues": [ "t3.micro", "t3.small", "t3.medium" ], "Default": "t3.micro" } }, "Resources":{ "myLaunchConfig":{ "Type":"AWS::AutoScaling::LaunchConfiguration", "Properties":{ "ImageId":{ "Ref":"LatestAmiId" }, "SecurityGroups":[ { "Ref":"myEC2SecurityGroup" } ], "InstanceType":{ "Ref":"InstanceType" }, "BlockDeviceMappings":[ { "DeviceName":"/dev/sda1", "Ebs":{ "VolumeSize":"30", "VolumeType":"gp2" } }, { "DeviceName":"/dev/sdm", "Ebs":{ "VolumeSize":"100", "DeleteOnTermination":"false" } } ] } } } }

YAML

--- AWSTemplateFormatVersion: 2010-09-09 Parameters: LatestAmiId: Description: Region specific image from the Parameter Store Type: 'AWS::SSM::Parameter::Value<AWS::EC2::Image::Id>' Default: '/aws/service/ami-amazon-linux-latest/amzn2-ami-hvm-x86_64-gp2' InstanceType: Description: Amazon EC2 instance type for the instances Type: String AllowedValues: - t3.micro - t3.small - t3.medium Default: t3.micro Resources: myLaunchConfig: Type: AWS::AutoScaling::LaunchConfiguration Properties: ImageId: !Ref LatestAmiId SecurityGroups: - Ref: "myEC2SecurityGroup" InstanceType: Ref: "InstanceType" BlockDeviceMappings: - DeviceName: /dev/sda1 Ebs: VolumeSize: 30 VolumeType: "gp2" - DeviceName: /dev/sdm Ebs: VolumeSize: 100 DeleteOnTermination: "false"

Instance store-backed AMI with Spot price and IAM role

This example shows a launch configuration that launches Spot Instances in the Auto Scaling group. This launch configuration will only be active if the current Spot price is less than the price in the template specification (0.045). It also demonstrates a launch configuration that uses the IamInstanceProfile property. For an example of a full template, including the definition of, and further references from the InstanceProfile object referenced here as RootInstanceProfile, see auto_scaling_with_instance_profile.template.

In this example, the ImageId property of the AWS::AutoScaling::LaunchConfiguration references the latest Amazon Linux AMI (instance store/S3-backed image) from the Parameter Store. The BlockDeviceMappings property lists a virtual device ephemeral0 mapped to /dev/sdc.

JSON

{ "AWSTemplateFormatVersion": "2010-09-09", "Parameters": { "LatestAmiId": { "Description": "Region specific image from the Parameter Store", "Type": "AWS::SSM::Parameter::Value<AWS::EC2::Image::Id>", "Default": "/aws/service/ami-amazon-linux-latest/amzn-ami-hvm-x86_64-s3" } }, "Resources":{ "myLaunchConfig":{ "Type":"AWS::AutoScaling::LaunchConfiguration", "Properties":{ "ImageId":{ "Ref":"LatestAmiId" }, "SecurityGroups":[ { "Ref":"myEC2SecurityGroup" } ], "InstanceType":"m3.medium", "SpotPrice":"0.045", "IamInstanceProfile":{ "Ref":"RootInstanceProfile" }, "BlockDeviceMappings": [ { "DeviceName": "/dev/sdc", "VirtualName": "ephemeral0" } ] } } } }

YAML

--- AWSTemplateFormatVersion: 2010-09-09 Parameters: LatestAmiId: Description: Region specific image from the Parameter Store Type: 'AWS::SSM::Parameter::Value<AWS::EC2::Image::Id>' Default: '/aws/service/ami-amazon-linux-latest/amzn-ami-hvm-x86_64-s3' Resources: myLaunchConfig: Type: AWS::AutoScaling::LaunchConfiguration Properties: ImageId: !Ref LatestAmiId SecurityGroups: - !Ref myEC2SecurityGroup InstanceType: m3.medium SpotPrice: "0.045" IamInstanceProfile: !Ref RootInstanceProfile BlockDeviceMappings: - DeviceName: /dev/sdc VirtualName: ephemeral0

Provisioned IOPS EBS-optimized volume with key-pair name and user data

This example demonstrates a launch configuration that configures the EbsOptmized property to launch instances with a provisioned IOPS EBS-optimized volume. This can increase the performance of your EBS-backed instances.

Note

For instances that are not EBS–optimized by default, you must enable EBS optimization to achieve the level of performance described in the Amazon EBS-optimized instances documentation in the Amazon Elastic Compute Cloud User Guide. For current generation instance types, EBS-optimization is enabled by default at no additional cost. Enabling EBS optimization for a previous generation instance type that is not EBS-optimized by default incurs additional fees.

When you use a launch configuration such as this one, your m1.large instances will contain optimized EBS root volumes with the provisioned IOPS settings that you specified in the AMI. Because you cannot specify the IOPS settings in a launch configuration, the AMI must be configured with a block device mapping that specifies the desired number of IOPS. The following are key attributes of this EBS-optimized instance configuration:

  • An instance type of m1.large or greater. This is required for EBS optimization. This optimization is only available for certain instance types and sizes.

  • An EBS-backed AMI with a volume type of io1 and the number of IOPS you want to provision for the volume.

  • The size of the EBS volume must accommodate the IOPS you need. There is a 50:1 ratio between IOPS and Gibibytes (GiB) of storage.

For more information about IOPS performance with provisioned IOPS volumes, see Provisioned IOPS SSD (io1 and io2) volumes in the Amazon Elastic Compute Cloud User Guide.

For more performance tips, see Amazon EBS volume performance on Linux instances in the Amazon Elastic Compute Cloud User Guide.

JSON

{ "Resources":{ "myLaunchConfig":{ "Type":"AWS::AutoScaling::LaunchConfiguration", "Properties":{ "ImageId":"ami-02354e95b39ca8dec", "SecurityGroups":[ { "Ref":"myEC2SecurityGroup" }, "myExistingEC2SecurityGroup" ], "InstanceType":"m1.large", "KeyName":{ "Ref":"KeyName" }, "UserData": {"Fn::Base64": {"Fn::Join": ["", [ "#!/bin/bash -x\n", "/opt/aws/bin/cfn-init -v --stack ", {"Ref": "AWS::StackName"}, " --resource myLaunchConfig ", " --configsets default ", " --region ", {"Ref": "AWS::Region"}, "\n", "/opt/aws/bin/cfn-signal -e $? --stack ", {"Ref": "AWS::StackName"}, " --resource myASG ", " --region ", {"Ref": "AWS::Region"}, "\n" ]]}}, "EbsOptimized":"true" } } } }

YAML

--- Resources: myLaunchConfig: Type: AWS::AutoScaling::LaunchConfiguration Properties: ImageId: "ami-02354e95b39ca8dec" SecurityGroups: - Ref: "myEC2SecurityGroup" - myExistingEC2SecurityGroup InstanceType: "m1.large" KeyName: Ref: "KeyName" UserData: !Base64 | #!/bin/bash -x yum install -y aws-cfn-bootstrap /opt/aws/bin/cfn-init -v --stack !Ref 'AWS::StackName' --resource myLaunchConfig --configsets default --region !Ref 'AWS::Region' /opt/aws/bin/cfn-signal -e $? --stack !Ref 'AWS::StackName' --resource myASG --region !Ref 'AWS::Region' EbsOptimized: "true"