» 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 supported:

name - (Optional) The name of the launch configuration. If you leave this blank, Terraform will auto-generate a unique name.
name_prefix - (Optional) Creates a unique name beginning with the specified prefix. Conflicts with name.
image_id - (Required) The EC2 image ID to launch.
instance_type - (Required) The size of instance to launch.
iam_instance_profile - (Optional) The name attribute of the IAM instance profile to associate with launched instances.
key_name - (Optional) The key name that should be used for the instance.
security_groups - (Optional) A list of associated security group IDS.
associate_public_ip_address - (Optional) Associate a public ip address with an instance in a VPC.
vpc_classic_link_id - (Optional) The ID of a ClassicLink-enabled VPC. Only applies to EC2-Classic instances. (eg. vpc-2730681a)
vpc_classic_link_security_groups - (Optional) The IDs of one or more security groups for the specified ClassicLink-enabled VPC (eg. sg-46ae3d11).
user_data - (Optional) The user data to provide when launching the instance. Do not pass gzip-compressed data via this argument; see user_data_base64 instead.
user_data_base64 - (Optional) Can be used instead of user_data to pass base64-encoded binary data directly. Use this instead of user_data whenever the value is not a valid UTF-8 string. For example, gzip-encoded user data must be base64-encoded and passed via this argument to avoid corruption.
enable_monitoring - (Optional) Enables/disables detailed monitoring. This is enabled by default.
ebs_optimized - (Optional) If true, the launched EC2 instance will be EBS-optimized.
root_block_device - (Optional) Customize details about the root block device of the instance. See Block Devices below for details.
ebs_block_device - (Optional) Additional EBS block devices to attach to the instance. See Block Devices below for details.
ephemeral_block_device - (Optional) Customize Ephemeral (also known as "Instance Store") volumes on the instance. See Block Devices below for details.
spot_price - (Optional; Default: On-demand price) The maximum price to use for reserving spot instances.
placement_tenancy - (Optional) The tenancy of the instance. Valid values are "default" or "dedicated", see AWS's Create Launch Configuration for more details

» 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.

The root_block_device mapping supports the following:

volume_type - (Optional) The type of volume. Can be "standard", "gp2", or "io1". (Default: "standard").
volume_size - (Optional) The size of the volume in gigabytes.
iops - (Optional) The amount of provisioned IOPS. This must be set with a volume_type of "io1".
delete_on_termination - (Optional) Whether the volume should be destroyed on instance termination (Default: true).

Modifying any of the root_block_device settings requires resource replacement.

Each ebs_block_device supports the following:

device_name - (Required) The name of the device to mount.
snapshot_id - (Optional) The Snapshot ID to mount.
volume_type - (Optional) The type of volume. Can be "standard", "gp2", or "io1". (Default: "standard").
volume_size - (Optional) The size of the volume in gigabytes.
iops - (Optional) The amount of provisioned IOPS. This must be set with a volume_type of "io1".
delete_on_termination - (Optional) Whether the volume should be destroyed on instance termination (Default: true).
encrypted - (Optional) Whether the volume should be encrypted or not. Do not use this option if you are using snapshot_id as the encrypted flag will be determined by the snapshot. (Default: false).

Modifying any ebs_block_device currently requires resource replacement.

Each ephemeral_block_device supports the following:

device_name - The name of the block device to mount on the instance.
virtual_name - The Instance Store Device Name (e.g. "ephemeral0")

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}".

NOTE: Changes to *_block_device configuration of existing resources cannot currently be detected by Terraform. After updating to block device configuration, resource recreation can be manually triggered by using the taint command.

» Attributes Reference

In addition to all arguments above, the following attributes are exported:

id - The ID of the launch configuration.
name - The name of the launch configuration.

» Import

Launch configurations can be imported using the name, e.g.

$ terraform import aws_launch_configuration.as_conf terraform-lg-123456