[Bug]: Empty tags on aws_eks_pod_identity_association causes drift

[calvinbui]

Terraform Core Version

1.8.2

AWS Provider Version

5.47.0

Affected Resource(s)

• aws_eks_pod_identity_association

Expected Behavior

No change in resource

No changes. Your infrastructure matches the configuration.

Actual Behavior

Change detected in with tags value.

Relevant Error/Panic Output Snippet

No response

Terraform Configuration Files

I am using the terraform-aws-modules/terraform-aws-eks-pod-identity module.

resource "aws_eks_pod_identity_association" "this" {
  for_each = { for k, v in var.associations : k => v if var.create }

  cluster_name    = try(each.value.cluster_name, var.association_defaults.cluster_name)
  namespace       = try(each.value.namespace, var.association_defaults.namespace)
  service_account = try(each.value.service_account, var.association_defaults.service_account)
  role_arn        = aws_iam_role.this[0].arn

  tags = merge(var.tags, try(each.value.tags, var.association_defaults.tags, {}))
}

Steps to Reproduce

1. Create aws_eks_pod_identity_association with no empty tags (tags = {})

  + resource "aws_eks_pod_identity_association" "this" {
      + association_arn = (known after apply)
      + association_id  = (known after apply)
      + cluster_name    = "mycluster"
      + id              = (known after apply)
      + namespace       = "kube-system"
      + role_arn        = "arn:aws:iam::1234567890:role/aws-ebs-csi-driver-20240426012547740300000001"
      + service_account = "ebs-csi-controller-sa"
      + tags            = {}
      + tags_all        = {
          + "ortto.com/env"           = "xxx"
          + "ortto.com/owner"         = "xxx"
          + "ortto.com/project"       = "xxx"
          + "ortto.com/repo"          = "xxx"
          + "ortto.com/role"          = "xxx"
        }
    }

2. Run another plan and see the resource has drifted with empty tags, even on subsequent applies.

  # module.pod_identity.aws_eks_pod_identity_association.this["xxx"] will be updated in-place
  ~ resource "aws_eks_pod_identity_association" "this" {
        id              = "a-xxx"
      + tags            = {}
        # (7 unchanged attributes hidden)
    }

However is tags is NOT empty, a tag is created, and the module does not detect a drift on the next run.

The tags_all tags from default_tags work and are present on the AWS resource.

Debug Output

No response

Panic Output

No response

Important Factoids

No response

References

Same issue faced in terraform-aws-modules/terraform-aws-eks-pod-identity#7 and referred here.

Would you like to implement a fix?

No

[github-actions]

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[aristosvo]

Hi @calvinbui!

I am not 100% sure this is an resource issue, it might be a configuration issue. Have you tried null instead of {} already?

[calvinbui]

Hi @calvinbui!

I am not 100% sure this is an resource issue, it might be a configuration issue. Have you tried null instead of {} already?

yep that seems like the case.

• {} --> drift
• null --> no drift
• removed the tag key --> no drift

i'll raise the issue back over in the module repo

[github-actions]

Warning

This issue has been closed, meaning that any additional comments are hard for our team to see. Please assume that the maintainers will not see them.

Ongoing conversations amongst community members are welcome, however, the issue will be locked after 30 days. Moving conversations to another venue, such as the AWS Provider forum, is recommended. If you have additional concerns, please open a new issue, referencing this one where needed.

[github-actions]

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