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Fixed: Invalid Backend Files from Empty Configuration

· 2 min read
Erik Osterman
Erik Osterman
Founder @ Cloud Posse

Atmos now validates that remote backend configurations are not empty before generating backend files. This prevents invalid Terraform configurations that would fail during terraform init.

The Problem​

When backend_type was set to a remote backend like s3, but the backend section was empty or missing required fields, Atmos would generate an invalid backend configuration:

# Stack configuration with empty backend
components:
  terraform:
    my-component:
      backend_type: s3
      backend: {}  # Empty!

This produced invalid backend.tf.json:

{
  "terraform": {
    "backend": {
      "s3": {}
    }
  }
}

Running terraform init with this configuration would fail because S3 backends require at minimum bucket and key fields.

The Fix​

Atmos now validates that the backend section is not empty when using remote backends (s3, gcs, azurerm, cloud). If the configuration is empty, Atmos skips backend generation with a helpful warning:

Skipping backend generation: 'backend' section is empty but 'backend_type' requires configuration.
Set 'components.terraform.auto_generate_backend_file: false' in atmos.yaml to disable.

The local backend is still allowed to have an empty configuration since Terraform supports it without any required fields.

Example​

Correct configuration with required backend fields:

components:
  terraform:
    my-component:
      backend_type: s3
      backend:
        bucket: "my-terraform-states"
        key: "terraform.tfstate"
        region: "us-east-1"
        dynamodb_table: "terraform-locks"

Upgrade​

Upgrade Atmos to get this validation. If you see the warning, add the required backend configuration fields for your backend type.