Why Terraform? What it really does in production

Your first real Terraform run: write a file, plan, apply, look at state, change something, and clean up. terraform_data, which is built in, stands in for a real resource, so you need no cloud account and it costs nothing.

You need: Terraform 1.4 or newer (install guide) or OpenTofu (install guide), and a terminal.

1. Make a folder with one file, main.tf

resource "terraform_data" "hello" {
  input = "my first resource"
}

output "message" {
  value = terraform_data.hello.output
}

2. Set up, then preview

terraform init
terraform plan

This is the real plan output from our test run, in full:

  # terraform_data.hello will be created
  + resource "terraform_data" "hello" {
      + id     = (known after apply)
      + input  = "my first resource"
      + output = (known after apply)
    }

Plan: 1 to add, 0 to change, 0 to destroy.

Notice (known after apply): the ID doesn't exist until the resource is really created.

3. Make it real, and see what state remembers

terraform apply
terraform state list

Type yes. You'll see message = "my first resource", and state lists terraform_data.hello.

4. Change your mind

Edit the input to "my changed resource", then:

terraform plan

# terraform_data.hello will be updated in-place and Plan: 0 to add, 1 to change, 0 to destroy. Terraform works out the difference between your file and what exists.

5. Clean up

terraform destroy

Type yes: Destroy complete! Resources: 1 destroyed.

Outputs above are real, captured with OpenTofu 1.12.6 on 3 October 2026, where the header line says "OpenTofu will perform the following actions" instead of "Terraform will…". Not run with the Terraform program itself, whose download is blocked in our test environment.