Use Terraform for_each with a module to provision per-environment infrastructure with environment-specific variable maps

Steps

1. Define a variable of type map(object(...)): variable "environments" { type = map(object({ region = string; instance_type = string; min_capacity = number })) }
2. Populate the variable in terraform.tfvars or via a .tfvars file per environment: environments = { staging = { region = "us-east-1"; instance_type = "t3.medium"; min_capacity = 1 }; prod = { region = "us-east-1"; instance_type = "m6i.large"; min_capacity = 3 } }
3. Use for_each in the module call: module "env" { for_each = var.environments; source = "./modules/app-environment"; region = each.value.region; instance_type = each.value.instance_type }
4. Inside the child module, use each.key as a name prefix for resources to avoid naming collisions: name = "${each.key}-cluster"
5. Run terraform plan and confirm two module instances appear: module.env["staging"] and module.env["prod"] with their respective configurations
6. To add a new environment, add it to the map variable and run terraform plan / apply — only the new environment's resources are created, existing environments are unaffected