CODEWITHSUNDEEP
terraformterraform-provider-aws
hosselausso
hosselausso

Reputation: 1087

How to enable/disable disk according to variable in Terraform-AWS?

I want to create a AWS instance and according to a variable, create an additional disk or not. This would allow me keeping the same .tf file and just specify via command line variables when I need the disk.

...
variable "create-extra-disk" {
    default=false
}
...
resource "aws_instance" "my_instance" {
    count           = "${var.instance_count}"
    ami             = "${var.image_id}"
    instance_type   = "${var.type}"
    key_name        = "${aws_key_pair.my-keypair.key_name}"
    security_groups = ["${aws_security_group.basic_sg.name}"]

    ebs_block_device {
        # enable = "${var.create-extra-disk}" # I'd like something like this
        device_name = "/dev/sdb"
        volume_size = 100
        volume_type = "gp2"
        delete_on_termination = true
    }
    ...

Upvotes: 0

Views: 915

Answers (2)

RyanKim
RyanKim

Reputation: 1785

You can use separated resources for ec2, ebs, and ebs attachment for configurability, https://www.terraform.io/docs/providers/aws/r/ebs_volume.html https://www.terraform.io/docs/providers/aws/r/volume_attachment.html

Above code seems to be terraform 0.11 or under,

variable "create-extra-disk" {
  default = true
} 

resource "aws_instance" "my_instance" {
  count         = "${var.instance_count}"
  ...
}

resource "aws_ebs_volume" "additional" {
  count             = "${var.create-extra-disk == true ? var.instance_count : 0}"
  availability_zone = "${var.region}"
  size              = 100
  type              = "gp2"
}

resource "aws_volume_attachment" "ebs_att" {
  count       = "${var.create-extra-disk == true ? var.instance_count : 0}"
  device_name = "/dev/sdb"
  volume_id   = "${element(aws_ebs_volume.additional.*.id, count.index)}"
  instance_id = "${element(aws_instance.my_instance.*.id, count.index)}"
}

Upvotes: 1

Mahattam
Mahattam

Reputation: 5763

You need to create two resources and use of count with a variable to include the condition to run the extra disk part, all this would be in the single file.

...
variable "create-extra-disk" {
default=false
}
...
resource "aws_instance" "my_instance" {
count           = "${var.instance_count && var.create-extra-disk == true ? 1 : 0}"
ami             = "${var.image_id}"
instance_type   = "${var.type}"
key_name        = "${aws_key_pair.my-keypair.key_name}"
security_groups = ["${aws_security_group.basic_sg.name}"]
}

resource "aws_instance" "my_instance_with_ebs" {
count           = "${var.instance_count && var.create-extra-disk == true ? 1 : 0 }"
ami             = "${var.image_id}"
instance_type   = "${var.type}"
key_name        = "${aws_key_pair.my-keypair.key_name}"
security_groups = ["${aws_security_group.basic_sg.name}"]

ebs_block_device {
    device_name = "/dev/sdb"
    volume_size = 100
    volume_type = "gp2"
    delete_on_termination = true
}

Upvotes: 0

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