How to interpolate count.index in the tags resource of an aws_ebs_volume

[Jonah]

Hi all,

I'm trying to use count.index to add tags to volumes attached to some aws instance created with count = N. This is the complete Terraform code:

resource "aws_instance" "prod-db" {
  ami           = "ami-xxxxxxxx"
  instance_type = "r4.2xlarge"
  key_name      = "operation-prod"
  availability_zone = "${var.availability-zones[count.index%2]}"
  subnet_id     = "${var.prod-db-subnets[var.availability-zones[count.index%2]]}"
  vpc_security_group_ids = ["sg-xxxxxx", "sg-yyyyyy", "sg-zzzzzz", "sg-kkkkkk"]
  ebs_optimized = "true"

  tags = "${merge(
    local.common_tags,
    map(
      "Name", "prod-db${count.index+1}",
      "Product", "xx",
      "Role", "yy",
    )
  )}"

  iam_instance_profile = "prod-db"

  count = 2
}
resource "aws_ebs_volume" "prod-db_opt" {
  availability_zone = "${element(aws_instance.prod-db.*.availability_zone, count.index)}"
  size = 20
  tags = "${aws_instance.prod-db.0.tags}"

  count = 2

}

This code is syntactically correct but the tag Name will be "prod-db1" for all the volumes. I couldn't find a way to replace "aws_instance.prod-db.0.tags" with "aws_instance.prod-db.N.tags" where N is the expansion of ${count.index} so that each volume has the same name of the attached instance.

[Matthew Ceroni]

You set the tags to the tags of only the first instance resource. Just use element like you do for the attachment.

[Miroslav E. Hadzhiev]

You also need to put spaces between the "+" sign and the other chars.