Terraform apply fails when not providing AMI

[matheus-rdo]

Description

terraform apply fails when the "ami" property is not set. According to the documentation, this property is optional. I was expecting to use the default linux AMI.

module "ec2_instance" {
  source  = "terraform-aws-modules/ec2-instance/aws"
  version = "~> 3.0"

  name = "my_ec2"
  ami  = ""  ## default value

  # omit others...
}

Error

module.ec2_instance.aws_instance.this[0]: Creating...
╷
│ Error: Error launching source instance: MissingParameter: The request must contain the parameter ImageId
│       status code: 400, request id: 8d52454d-80f1-4056-9d1b-f973b65b013f
│
│   with module.ec2_instance.aws_instance.this[0],
│   on .terraform\modules\ec2_instance\main.tf line 5, in resource "aws_instance" "this":
│    5: resource "aws_instance" "this" {
│

Versions

• Terraform: Terraform v1.1.0
• Provider(s): Terraform v1.1.0
• Module: ec2-instance

[antonbabenko]

ami is actually required. More info here - https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/instance#ami

[matheus-rdo]

ami is actually required. More info here - https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/instance#ami

I was reading through the terraform-aws-modules documentation. It says the field is optional https://registry.terraform.io/modules/terraform-aws-modules/ec2-instance/aws/latest

Thanks!

[antonbabenko]

It is optional if you disable the creation of the module's resources like this:

https://github.com/terraform-aws-modules/terraform-aws-ec2-instance/blob/ab731d112e37971368066b5dbecf35b075a853aa/examples/complete/main.tf#L80-L84

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