RFE: support for no_device in aws_instance ephemeral_block_device

[mblakele]

Terraform Version

Terraform v0.7.1

Affected Resource(s)

Please list the resources as a list, for example:

• aws_instance

Terraform Configuration Files

resource "aws_instance" "test" {
  # Block ephemeral storage, which confuses the setup process.
  ephemeral_block_device {
    device_name = "/dev/sdb"
    no_device = "true"
    virtual_name = "ephemeral0"
  }
}

Expected Behavior

If I'm reading https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/block-device-mapping-concepts.html correctly, terraform should set NoDevice for the specified device_name.

To add volumes to an instance using the command line
...

For example, suppose that an EBS-backed AMI specifies the following block device mapping:

/dev/sdb=ephemeral0
/dev/sdh=snap-1234567890abcdef0
/dev/sdj=:100
To prevent /dev/sdj from attaching to an instance launched from this AMI, use the following mapping:

{
    "DeviceName": "/dev/sdj",
    "NoDevice": ""
}

Also virtual_name probably shouldn't be there when no_device is set — but terraform 0.7.1 requires it.

Actual Behavior

aws_instance.test: ephemeral_block_device.0: invalid or unknown key: no_device

Steps to Reproduce

1. terraform plan

Possible workaround: create the AMI without the ephemeral mappings. But I'd rather not do that because I'd have to maintain two AMIs and that would be the only difference between them.

[jweir]

This issue is burning me too. Packer had this issue and was fixed via hashicorp/packer@2a94b59

[timonwong]

Hi, when this issue is fixed, it should address #5390, when the BlockingMappingDevice from an AMI contains ephemerals, "NoDevice" have to be set on EBS-only instance, or the AutoRecover feature from AWS won't work.

[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.

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