Changes found in EBS Block device where there aren't really changes

[hashibot]

This issue was originally opened by @davedash as hashicorp/terraform#4786. It was migrated here as part of the provider split. The original body of the issue is below.

---

    ebs_block_device.#:                                "2" => "1"
    ebs_block_device.2659407853.delete_on_termination: "true" => "1" (forces new resource)
    ebs_block_device.2659407853.device_name:           "/dev/sdf" => "/dev/sdf" (forces new resource)
    ebs_block_device.2659407853.encrypted:             "true" => "1" (forces new resource)
    ebs_block_device.2659407853.iops:                  "150" => "<computed>"
    ebs_block_device.2659407853.snapshot_id:           "" => "<computed>"
    ebs_block_device.2659407853.volume_size:           "50" => "50" (forces new resource)
    ebs_block_device.2659407853.volume_type:           "gp2" => "gp2" (forces new resource)

I keep seeing this on a few instances. apply keeps recreating the instances and then they instances still do the above. These are on t2.small instances in EC2.

Here's the original tf:

resource "aws_instance" "instance" {
  ami = "${var.ami}"  # Ubuntu HVM
  instance_type = "${var.instance_type}"

  tags {
    Name = "${var.env}-${var.name}${var.name_suffix}"
    env = "${var.env}"
    role = "${var.env}-${var.name}"
  }

  ebs_block_device {
    encrypted = 1
    device_name = "/dev/sdf"
    volume_type = "gp2"
    volume_size = 50
  }

  security_groups = ["${split(",", var.security_groups)}"]

  subnet_id = "${element(split(",", var.subnets), var.number)}"

  iam_instance_profile = "${var.env}-${var.name}"
  ebs_optimized = "${var.ebs_optimized}"
  user_data = "${file(var.user_data)}"
  key_name = "davedash"

}

[hashibot]

This comment was originally opened by @wata727 as hashicorp/terraform#4786 (comment). It was migrated here as part of the provider split. The original comment is below.

---

Hi @davedash. I had the same problem.

ebs_block_device is additional block device. If you want to use it, specify root_block_device
When you only specify ebs_block_device, it create ebs_block_device as root_block_device automatically.
aws_instance attribute has root_block_device instead of ebs_block_device in terraform.tfstate
As a result, apply keeps recreating instances.

[hashibot]

This comment was originally opened by @davedash as hashicorp/terraform#4786 (comment). It was migrated here as part of the provider split. The original comment is below.

---

Okay… this makes sense.  

But I feel this is different than before, since almost all of my volumes use a root abs volume.  Does this behavior change based on instance size?  This happens to be my t2.small that trigger this.

-- 
Dave Dash

On January 24, 2016 at 5:40:56 AM, Kazuma Watanabe ([email protected]) wrote:

Hi @davedash. I had the same problem.

ebs_block_device is additional block device. If you want to use it, specify root_block_device
When you only specify ebs_block_device, it create ebs_block_device as root_block_device automatically.
aws_instance attribute has root_block_device instead of ebs_block_device in terraform.tfstate
As a result, apply keeps recreating instances.

—
Reply to this email directly or view it on GitHub.

[hashibot]

This comment was originally opened by @wata727 as hashicorp/terraform#4786 (comment). It was migrated here as part of the provider split. The original comment is below.

---

Sorry, I don't know condition that not happened this problem...
At least I can confirm that on t2.micro and m3.medium instance. The following output is caused on m3.medium instance:

-/+ aws_instance.server
    ami:                                               "ami-383c1956" => "ami-383c1956"
    associate_public_ip_address:                       "true" => "1"
    availability_zone:                                 "ap-northeast-1a" => "<computed>"
    disable_api_termination:                           "false" => "0"
    ebs_block_device.#:                                "0" => "1"
    ebs_block_device.3935708772.delete_on_termination: "" => "1" (forces new resource)
    ebs_block_device.3935708772.device_name:           "" => "/dev/xvda" (forces new resource)
    ebs_block_device.3935708772.encrypted:             "" => "<computed>" (forces new resource)
    ebs_block_device.3935708772.iops:                  "" => "<computed>" (forces new resource)
    ebs_block_device.3935708772.snapshot_id:           "" => "<computed>" (forces new resource)
    ebs_block_device.3935708772.volume_size:           "" => "8" (forces new resource)
    ebs_block_device.3935708772.volume_type:           "" => "gp2" (forces new resource)
    ephemeral_block_device.#:                          "0" => "<computed>"
    instance_initiated_shutdown_behavior:              "stop" => "stop"
    instance_type:                                     "m3.medium" => "m3.medium"
    ...

If you want to know about that, you should ask in AWS developer forum. https://forums.aws.amazon.com/tags/ec2?categoryID=9

[hashibot]

This comment was originally opened by @simonluijk as hashicorp/terraform#4786 (comment). It was migrated here as part of the provider split. The original comment is below.

---

I am seeing this too. But it is not related to root_block_device. In my case (and I suspect the OP's too) it is caused by an aws_volume_attachment to the same instance. Whenever Terraform refreshes it adds the volume attached with the aws_volume_attachment to ebs_block_device.4278008646.* in the state file. When creating the plan it wants to remove this device as there is no ebs_block_device definition for it.

[hashibot]

This comment was originally opened by @mxs as hashicorp/terraform#4786 (comment). It was migrated here as part of the provider split. The original comment is below.

---

I am seeing this also, like OP i have ebs_block_device in my aws_instance config. I don't have a aws_volume_attachment config.

ebs_block_device.#:                                "2" => "1"
    ebs_block_device.2250803247.delete_on_termination: "false" => "0" (forces new resource)
    ebs_block_device.2250803247.device_name:           "/dev/sdp" => "/dev/sdp" (forces new resource)
    ebs_block_device.2250803247.encrypted:             "false" => "<computed>"
    ebs_block_device.2250803247.iops:                  "6" => "<computed>"
    ebs_block_device.2250803247.snapshot_id:           "" => "<computed>"
    ebs_block_device.2250803247.volume_size:           "2" => "2" (forces new resource)
    ebs_block_device.2250803247.volume_type:           "gp2" => "gp2" (forces new resource)
    ebs_block_device.504524833.delete_on_termination:  "1" => "0"
    ebs_block_device.504524833.device_name:            "/dev/xvdcz" => ""

[hashibot]

This comment was originally opened by @davedash as hashicorp/terraform#4786 (comment). It was migrated here as part of the provider split. The original comment is below.

---

Even with

  lifecycle {
    ignore_changes = ["ebs_block_device", "root_block_device"]
  }

I still get issues:

-/+ module.dev.docker-instance.aws_instance.instance
    ami:                        "ami-2b3b6041" => "ami-2b3b6041"
    availability_zone:          "us-east-1a" => "<computed>"
    ebs_optimized:              "false" => "0"
    ephemeral_block_device.#:   "0" => "<computed>"
    iam_instance_profile:       "dev-docker" => "dev-docker"
    instance_state:             "running" => "<computed>"
    instance_type:              "t2.small" => "t2.small"
    key_name:                   "davedash" => "davedash"
    placement_group:            "" => "<computed>"
    public_dns:                 "" => "<computed>"
    public_ip:                  "" => "<computed>"
    security_groups.#:          "2" => "2"
    security_groups.1667421418: "sg-e74eff81" => "sg-e74eff81"
    security_groups.4253194611: "sg-fee58e9a" => "sg-fee58e9a"
    source_dest_check:          "true" => "1"
    subnet_id:                  "subnet-130abe38" => "subnet-130abe38"
    tags.#:                     "3" => "3"
    tags.Name:                  "dev-docker" => "dev-docker"
    tags.env:                   "dev" => "dev"
    tags.role:                  "dev-docker" => "dev-docker"
    tenancy:                    "default" => "<computed>"
    user_data:                  "50d98c37ef90b3a8b5453959d9217578748579e9" => "50d98c37ef90b3a8b5453959d9217578748579e9"
    vpc_security_group_ids.#:   "2" => "<computed>"

[hashibot]

This comment was originally opened by @ashb as hashicorp/terraform#4786 (comment). It was migrated here as part of the provider split. The original comment is below.

---

@davedash That last comment is known and being tracked in hashicorp/terraform#5627

[github-actions]

Marking this issue as stale due to inactivity. This helps our maintainers find and focus on the active issues. If this issue receives no comments in the next 30 days it will automatically be closed. Maintainers can also remove the stale label.

If this issue was automatically closed and you feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. Thank you!

[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!