RDS enabled_cloudwatch_logs_exports - InvalidParameterCombination: No modifications were requested

[Constantin07]

Terraform Version

Terraform v0.11.10

Affected Resource(s)

aws_db_instance

Terraform Configuration Files

RDS instance with the below attribute configuration.

enabled_cloudwatch_logs_exports = ["audit", "slowquery", "error"]

Debug Output

------------------------------------------------------------------------

An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:
  ~ update in-place

Terraform will perform the following actions:

  ~ module.db.module.db_instance.aws_db_instance.this
      enabled_cloudwatch_logs_exports.1: "error" => "slowquery"
      enabled_cloudwatch_logs_exports.2: "slowquery" => "error"

Plan: 0 to add, 1 to change, 0 to destroy.

------------------------------------------------------------------------

This plan was saved to: /dev/uat_out.txt

To perform exactly these actions, run the following command to apply:

    terraform apply "/dev/uat_out.txt"

module.db.module.db_instance.aws_db_instance.this: Modifying... (ID: dev-ew1-mu-db-rds)
  enabled_cloudwatch_logs_exports.1: "error" => "slowquery"
  enabled_cloudwatch_logs_exports.2: "slowquery" => "error"

Error: Error applying plan:

1 error(s) occurred:

* module.db.module.db_instance.aws_db_instance.this: 1 error(s) occurred:
* aws_db_instance.this: Error modifying DB Instance dev-ew1-mu-db-rds: InvalidParameterCombination: No modifications were requested
	status code: 400, request id: d80dcacc-33f0-49ba-95c2-2796d5c09ff9

Terraform does not automatically rollback in the face of errors.
Instead, your Terraform state file has been partially updated with
any resources that successfully completed. Please address the error
above and apply again to incrementally change your infrastructure.

Expected Behavior

On subsequent runs it shouldn't detect any changes.

Actual Behavior

If I re-run the plan - it keeps saying that there is an update required.
See the plan output - it just tries to change order.

Steps to Reproduce

run terraform apply on a RDS instance with enabled_cloudwatch_logs_exports enabled and then try to re-run the plan agin.

Important Factoids

It looks like the ordering in enabled_cloudwatch_logs_exports is important.
If I set it like this it works fine.

enabled_cloudwatch_logs_exports = ["audit", "error", "slowquery"]

Note: The documentation doesn't mention that the list should be alphabetically ordered to work properly.

[bflad]

The fix for this has been merged and will release with version 3.9.0 of the Terraform AWS Provider, likely tomorrow. 👍

[ghost]

This has been released in version 3.9.0 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 for triage. Thanks!

[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!