aws_instance: for inline EBS volumes, throughput is ignored if iops are specified

[matthiasr]

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Terraform CLI and Terraform AWS Provider Version

Terraform v0.14.5

• provider registry.terraform.io/hashicorp/aws v3.25.0
• provider registry.terraform.io/hashicorp/external v2.0.0
• provider registry.terraform.io/hashicorp/template v2.2.0

Affected Resource(s)

• aws_instance resource

Terraform Configuration Files

Please include all Terraform configurations required to reproduce the bug. Bug reports without a functional reproduction may be closed without investigation.

provider "aws" {
  region = "eu-west-1"
}

resource "aws_instance" "ebs" {
  count         = 1
  ami           = "ami-043cb8e8f53c04caf"
  instance_type = "t3.micro"
  subnet_id     = "[redacted]"

  root_block_device {
    volume_size = 250
    volume_type = "gp3"

    iops       = 4000
    throughput = 300
  }
}

Debug Output

https://gist.github.com/matthiasr/463670006387c005e78d42910a78f822

Expected Behavior

Root EBS volume has throughput 300

Actual Behavior

EBS volume has throughput 125.

I tested this separately for the ebs_block_device and it shows the same behavior. I believe the ebs_volume resource does not have this issue, but have not extensively tested it as we mostly use inline volumes.

Steps to Reproduce

1. terraform plan the above HCL
2. note that the plan says throughput = 300
3. apply the plan
4. terraform state show aws_instance.ebs[0] shows throughput = 125 (as does the EC2 console)

Important Factoids

I think I see where this is happening in the code, and will submit a PR shortly.

References

• aws_instance: Support for gp3 volumes #16620 introduced support for throughput

[ghost]

This has been released in version 3.28.0 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!