Terragrunt: keeping 30 environments DRY

Stop copy-pasting backend and provider blocks across environments — generate them and keep inputs in one place.

At thirty environments, plain Terraform means thirty near-identical backend and provider blocks that drift the moment someone edits one. Terragrunt generates the boilerplate from a single root file and keeps only the per-environment inputs in each leaf — DRY without magic.

Define the backend once

remote_state {
  backend = "s3"
  generate = { path = "backend.tf", if_exists = "overwrite" }
  config = {
    bucket = "acme-tfstate"
    key    = "${path_relative_to_include()}/terraform.tfstate"
    region = "eu-west-1"
    encrypt = true
  }
}

Each environment is just inputs

include "root" { path = find_in_parent_folders() }
terraform { source = "git::[email protected]:acme/modules.git//app?ref=v2.1" }
inputs = {
  instance_count = 6
  environment    = "prod"
}

Operate the whole tree

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