amazon eks - How to create a state file and acquire lock at parent level in Terraform with modular structure? - Stack Overflow

I have a modular Terraform structure managed with Terragrunt, and I want to maintain the modularity of my configuration. However, I need to create and manage the state file and acquire locks at the parent directory level.

Here’s my current project structure:

.
├── backend-config.yml
├── backend.tf
├── core-dns-csi-driver-addon
│   ├── terragrunt.hcl
├── eks
│   ├── terragrunt.hcl
├── karpenter
│   ├── terragrunt.hcl
├── kube-proxy-vpc-cni-addon
│   ├── terragrunt.hcl
├── local-swarm-nodegroup
│   ├── terragrunt.hcl
├── loki
│   ├── terragrunt.hcl
├── metrics-server
│   ├── terragrunt.hcl
├── provider.tf
├── storageclass
│   ├── terragrunt.hcl
├── terragrunt.hcl  # Parent-level configuration
├── update_yaml.py
└── vpc
    ├── terragrunt.hcl

Requirements:

• State File: A single shared state file at the parent level (e.g., root directory).
• Locking: State file locking using DynamoDB or another mechanism at the parent level.
• Modularity: Retain the modular structure with separate terragrunt.hcl files for each module (e.g., eks, vpc, etc.).

What I Have Tried:

1. Terragrunt Root Configuration:

   Created a root terragrunt.hcl file with the shared back-end configuration:

   remote_state {
     backend = "s3"
     config = {
       bucket         = "my-terraform-state"
       key            = "terraform/parent-level-state.tfstate"
       region         = "us-east-1"
       dynamodb_table = "eks-locks"
       encrypt        = true
     }
   }
   

2. Child Module Configuration:

   Referenced the parent configuration in each module's terragrunt.hcl file:

   include {
     path = find_in_parent_folders()
   }
   

How can I configure Terragrunt to enforce a single state file and locking mechanism at the parent level while keeping the modular structure intact?

How can I apply and destroy at module level, keeping state file intact at parent level?

Is there a better approach to managing modular Terraform configurations with shared state and lock files at the parent level?