[Bug]: v5.68.0 ConcurrentModification error when using aws_iam_role with inline_policy

[lorengordon]

Terraform Core Version

1.9.5

AWS Provider Version

5.68.0

Affected Resource(s)

• aws_iam_role

Expected Behavior

Terraform apply should complete successfully, creating the IAM Role and attaching all inline policies specified by the inline_policy blocks.

Actual Behavior

Terraform attempts too many simultaneous operations, and the AWS API reports a ConcurrentModification error.

Relevant Error/Panic Output Snippet

│ Error: creating IAM Role (tardigrade-role-epsilon-kwinax): operation error IAM: CreateRole, https response error StatusCode: 409, RequestID: 00a5d8fd-70f5-45c1-9293-7004e1f5299a, ConcurrentModification:
│
│   with module.create_roles["tardigrade-role-epsilon-kwinax"].aws_iam_role.this,
│   on ../../modules/role/main.tf line 2, in resource "aws_iam_role" "this":
│    2: resource "aws_iam_role" "this" {

Terraform Configuration Files

https://github.com/plus3it/terraform-aws-tardigrade-iam-principals/tree/master/tests/create_roles

Steps to Reproduce

Run init and apply in the create_roles/prereq directory.
Run init and apply in the create_roles directory.

Debug Output

No response

Panic Output

No response

Important Factoids

Possibly related to changes from the new exclusive pattern? #39203

References

No response

Would you like to implement a fix?

None

[github-actions]

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[lorengordon]

Fwiw, if I downgrade to v5.67.0, then the error goes away. So pretty sure the problem is coming from something introduced in v5.68.0.

[lorengordon]

Hmm, nope, just a race condition. 5.67.0 is affected also. I guess maybe the error response is new, and not currently handled in the retryable errors logic?

[jar-b]

This is an odd one. We don't retry this error during role creation or inline policy creation (either via inline_policy or aws_iam_role_policy). Adding retry logic seems a reasonable solution.

That said, I'm a bit confused how this happens on CreateRole, which should be the first operation before anything else could happen concurrently. Perhaps there is some nuance with propagation of changes when roles are deleted and re-created? Either way, if it's happening often enough to reproduce across multiple provider versions we should attempt a fix. I'll assign myself.

[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]

This functionality has been released in v5.69.0 of the Terraform AWS Provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template. Thank you!

[lorengordon]

Thanks @jar-b! I just tested several times with v5.69.0 and the issue indeed appears resolved. Appreciate the quick patch!

[github-actions]

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.
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