AWS EKS Introduction - Incorrect attribute value type

[jonigl]

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Terraform Version

Terraform v0.12.1

• provider.aws v2.14.0
• provider.http v1.1.1

Affected Resource(s)

• aws_eks_cluster
• aws_autoscaling_group

Terraform Configuration Files

resource "aws_autoscaling_group" "demo" {
  desired_capacity     = 2
  launch_configuration = "${aws_launch_configuration.demo.id}"
  max_size             = 5
  min_size             = 1
  name                 = "terraform-eks-demo"
  vpc_zone_identifier  = ["${aws_subnet.demo.*.id}"] #<--- Here it's one error

  tag {
    key                 = "Name"
    value               = "terraform-eks-demo"
    propagate_at_launch = true
  }

  tag {
    key                 = "kubernetes.io/cluster/${var.cluster-name}"
    value               = "owned"
    propagate_at_launch = true
  }
}

resource "aws_eks_cluster" "demo" {
  name     = "${var.cluster-name}"
  role_arn = "${aws_iam_role.demo-cluster.arn}"

  vpc_config {
    security_group_ids = ["${aws_security_group.demo-cluster.id}"]
    subnet_ids         = ["${aws_subnet.demo.*.id}"] #<--- Here it's the other error
  }

  depends_on = [
    "aws_iam_role_policy_attachment.demo-cluster-AmazonEKSClusterPolicy",
    "aws_iam_role_policy_attachment.demo-cluster-AmazonEKSServicePolicy",
  ]
}

Expected Behavior

Apply without any errors

Actual Behavior

Error: Incorrect attribute value type
  on eks-cluster.tf line 80, in resource "aws_eks_cluster" "demo":
  80:     subnet_ids         = ["${aws_subnet.demo.*.id}"]
Inappropriate value for attribute "subnet_ids": element 0: string required.

Error: Incorrect attribute value type
  on eks-worker-nodes.tf line 132, in resource "aws_autoscaling_group" "demo":
 132:   vpc_zone_identifier  = ["${aws_subnet.demo.*.id}"]
Inappropriate value for attribute "vpc_zone_identifier": element 0: string
required.

Steps to Reproduce

Try this example: https://github.com/terraform-providers/terraform-provider-aws/tree/master/examples/eks-getting-started

1. terraform apply

References

• Terraform 0.12 + vpc module v2.2 (Inappropriate value for attribute "subnet_ids": element 0: string required.) terraform-aws-modules/terraform-aws-vpc#271

Possible Solution

I used flatten () as @marcincuber suggested in terraform-aws-modules/terraform-aws-vpc#271 to resolve these errors and it worked:

flatten(["${aws_subnet.demo.*.id}"])
flatten(["${aws_subnet.demo.*.id}"])

[bflad]

Related #8950

[dev-e]

Related #401 and #414

[bflad]

Hi folks 👋 This issue was resolved as part of work we did to begin automatically verifying all configurations against Terraform 0.12 in the examples/ directory of the repository. Please open a new issue if there are any continuing issues. 👍

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. Thanks!