Unconfigurable attribute "domain" error in EC2 module with EIP enabled

[f3-esajid]

Description

I'm encountering an error when setting create_eip = true in the module. The module fails during apply with the following error:

Error: Value for unconfigurable attribute

  with module.ec2_instance.aws_eip.this,
  on .terraform/modules/ec2_instance/main.tf line 619, in resource "aws_eip" "this":
  619:   domain = var.eip_domain

Can't configure a value for "domain": its value will be decided automatically based on the result of applying this configuration.

It appears the module is explicitly setting the domain argument on the aws_eip resource, which is now inferred automatically by the AWS provider and should no longer be set manually.

Minimal reproducible configuration:

module "ec2_instance" {
  source                        = "terraform-aws-modules/ec2-instance/aws"
  name                          = "test-ec2"
  ami                           = "ami-025685dfa31c58aa4"
  instance_type                 = "t3.micro"
  subnet_id                     = "subnet-12345678"
  vpc_security_group_ids        = ["sg-12345678"]
  associate_public_ip_address   = true
  create_eip                    = true
  monitoring                    = true
  disable_api_termination       = true
  instance_initiated_shutdown_behavior = "stop"
  create_iam_instance_profile   = true
  iam_role_name                 = "test-role"
  iam_instance_profile          = "test-profile"
  iam_role_policies = {
    AmazonSSMManagedInstanceCore = "arn:aws:iam::aws:policy/AmazonSSMManagedInstanceCore"
  }
  root_block_device = [{
    volume_type           = "gp3"
    volume_size           = 20
    delete_on_termination = true
  }]
}

• ✋ I have searched the open/closed issues and my issue is not listed.

⚠️ Note

• .terraform directory has been deleted
• Project was reinitialized with terraform init
• Issue confirmed to persist after retries

Versions

• Module version [Required]: v5.7.0
• Provider version(s):

provider registry.terraform.io/hashicorp/aws v5.51.0

Reproduction Code [Required]

module "ec2_instance" {
  source                        = "terraform-aws-modules/ec2-instance/aws"
  name                          = "test-ec2"
  ami                           = "ami-025685dfa31c58aa4"
  instance_type                 = "t3.micro"
  subnet_id                     = "subnet-12345678"
  vpc_security_group_ids        = ["sg-12345678"]
  associate_public_ip_address   = true
  create_eip                    = true
  monitoring                    = true
  disable_api_termination       = true
  instance_initiated_shutdown_behavior = "stop"
  create_iam_instance_profile   = true
  iam_role_name                 = "test-role"
  iam_instance_profile          = "test-profile"
  iam_role_policies = {
    AmazonSSMManagedInstanceCore = "arn:aws:iam::aws:policy/AmazonSSMManagedInstanceCore"
  }
  root_block_device = [{
    volume_type           = "gp3"
    volume_size           = 20
    delete_on_termination = true
  }]
}

Expected behavior

Terraform should provision the EC2 instance and automatically associate an Elastic IP using the module.

Actual behavior

Terraform errors during plan/apply due to unconfigurable domain argument being set inside the module.

Terminal Output Screenshot(s)

Error: Value for unconfigurable attribute
│ 
│   with module.ec2_instance.aws_eip.this,
│   on .terraform/modules/ec2_instance/main.tf line 619, in resource "aws_eip" "this":
│  619:   domain = var.eip_domain
│ 
│ Can't configure a value for "domain": its value will be decided automatically based on the result of applying this configuration.

Additional context

This likely stems from a change in AWS provider behavior where the domain attribute in aws_eip is now inferred automatically. The module should remove or guard against setting domain explicitly.

[f3-esajid]

creating new instances is getting break due to this