Terraform-provider-aws: No change when modifying aws_instance.ebs_block_device.volume_size

[hashibot[bot]]

_This issue was originally opened by @adaranutsa as hashicorp/terraform#17769. It was migrated here as a result of the provider split. The original body of the issue is below._

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I'm trying to resize the EBS volume within an ebs_block_device on an EC2 instance. Running plan or apply shows no changes are needed.

Terraform Version

Terraform v0.11.5
+ provider.aws v1.13.0

Affected Resource(s)

• aws_instance

Terraform Configuration Files

resource "aws_instance" "main" {
  ami                    = "ami-12345678"
  instance_type          = "t2.micro"
  vpc_security_group_ids = ["sg-12345678"]
  subnet_id              = "subnet-12345678"

  ebs_block_device {
    device_name = "xvdf"
    volume_size = "50"
    volume_type = "gp2"
    snapshot_id = "snap-1234567890abcdefg"
  }

  ebs_block_device {
    device_name = "xvdd"
    volume_size = "35"
    volume_type = "gp2"
    snapshot_id = "snap-1234567890abcdefg"
  }

  ebs_block_device {
    device_name = "xvde"
    volume_size = "40"
    volume_type = "gp2"
    snapshot_id = "snap-1234567890abcdefg"
  }
}

Expected Behavior

The EBS volume size should have been modified.

Actual Behavior

Nothing happens.

Apply complete! Resources: 0 added, 0 changed, 0 destroyed.

Steps to Reproduce

terraform apply

Change any ebs_block_device.volume_size to 100

terraform apply

Additional Context

I'm launching the instance from an AMI that already has the volumes configured. I'm simply creating the ebs_block_device blocks to match to the device_name on the AMI so that I can control the volume size. It works fine when deploying from scratch but when I try to change the volume size after the instance already exists, nothing happens.

References

This issue is the same as the following which seems to have been fixed but not for aws_instance.

14826

[catsby]

Hey there @adaranutsa – sorry to say that I believe this is a known limitation of Terraform with regards to block devices and aws_instance:

• https://www.terraform.io/docs/providers/aws/r/instance.html#block-devices

See the note on that page, copied here for reference:

NOTE: Currently, changes to *_block_device configuration of existing resources cannot be automatically detected by Terraform. After making updates to block device configuration, resource recreation can be manually triggered by using the taint command.

Sorry for the trouble!

I'm going to ping @bflad to see if hey can verify this limitation still exists.

[catsby]

Closing for now

[heldersepu]

Any update on this issue?
Would be nice if a fix was included in the next version...

[hashibot[bot]]

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!