Resource: aws_launch_configuration

Provides a resource to create a new launch configuration, used for autoscaling groups.

Example Usage

data "aws_ami" "ubuntu" {
  most_recent = true

  filter {
    name   = "name"
    values = ["ubuntu/images/hvm-ssd/ubuntu-trusty-14.04-amd64-server-*"]
  }

  filter {
    name   = "virtualization-type"
    values = ["hvm"]
  }

  owners = ["099720109477"] # Canonical
}

resource "aws_launch_configuration" "as_conf" {
  name          = "web_config"
  image_id      = data.aws_ami.ubuntu.id
  instance_type = "t2.micro"
}

Using with AutoScaling Groups

Launch Configurations cannot be updated after creation with the Amazon Web Service API. In order to update a Launch Configuration, Terraform will destroy the existing resource and create a replacement. In order to effectively use a Launch Configuration resource with an AutoScaling Group resource, it's recommended to specify create_before_destroy in a lifecycle block. Either omit the Launch Configuration name attribute, or specify a partial name with name_prefix. Example:

data "aws_ami" "ubuntu" {
  most_recent = true

  filter {
    name   = "name"
    values = ["ubuntu/images/hvm-ssd/ubuntu-trusty-14.04-amd64-server-*"]
  }

  filter {
    name   = "virtualization-type"
    values = ["hvm"]
  }

  owners = ["099720109477"] # Canonical
}

resource "aws_launch_configuration" "as_conf" {
  name_prefix   = "terraform-lc-example-"
  image_id      = data.aws_ami.ubuntu.id
  instance_type = "t2.micro"

  lifecycle {
    create_before_destroy = true
  }
}

resource "aws_autoscaling_group" "bar" {
  name                 = "terraform-asg-example"
  launch_configuration = aws_launch_configuration.as_conf.name
  min_size             = 1
  max_size             = 2

  lifecycle {
    create_before_destroy = true
  }
}

With this setup Terraform generates a unique name for your Launch Configuration and can then update the AutoScaling Group without conflict before destroying the previous Launch Configuration.

Using with Spot Instances

Launch configurations can set the spot instance pricing to be used for the Auto Scaling Group to reserve instances. Simply specifying the spot_price parameter will set the price on the Launch Configuration which will attempt to reserve your instances at this price. See the AWS Spot Instance documentation for more information or how to launch Spot Instances with Terraform.

data "aws_ami" "ubuntu" {
  most_recent = true

  filter {
    name   = "name"
    values = ["ubuntu/images/hvm-ssd/ubuntu-trusty-14.04-amd64-server-*"]
  }

  filter {
    name   = "virtualization-type"
    values = ["hvm"]
  }

  owners = ["099720109477"] # Canonical
}

resource "aws_launch_configuration" "as_conf" {
  image_id      = data.aws_ami.ubuntu.id
  instance_type = "m4.large"
  spot_price    = "0.001"

  lifecycle {
    create_before_destroy = true
  }
}

resource "aws_autoscaling_group" "bar" {
  name                 = "terraform-asg-example"
  launch_configuration = aws_launch_configuration.as_conf.name
}

Argument Reference

The following arguments are required:

The following arguments are optional:

Block devices

Each of the *_block_device attributes controls a portion of the AWS Launch Configuration's "Block Device Mapping". It's a good idea to familiarize yourself with AWS's Block Device Mapping docs to understand the implications of using these attributes.

Each AWS Instance type has a different set of Instance Store block devices available for attachment. AWS publishes a list of which ephemeral devices are available on each type. The devices are always identified by the virtual_name in the format ephemeral{0..N}.

Modifying any of the ebs_block_device settings requires resource replacement.

ephemeral_block_device

root_block_device

Attribute Reference

This resource exports the following attributes in addition to the arguments above:

Import

In Terraform v1.5.0 and later, use an import block to import launch configurations using the name. For example:

import {
  to = aws_launch_configuration.as_conf
  id = "terraform-lg-123456"
}

Using terraform import, import launch configurations using the name. For example:

% terraform import aws_launch_configuration.as_conf terraform-lg-123456