Why Infrastructure as Code

Manual infrastructure changes are untrackable, unreproducible, and error-prone. Infrastructure as code solves all three problems.

With Terraform, your infrastructure is versioned, reviewable, and reproducible. You can spin up a replica of production in minutes. You can see exactly what changed and when.

Project Structure

infra/
modules/
vpc/
ecs-cluster/
rds/
redis/
environments/
dev/
main.tf
variables.tf
staging/
main.tf
variables.tf
production/
main.tf
variables.tf

Modules are reusable. Environments are separate. This structure prevents configuration drift between environments.

State Management

Remote State

Never store state locally. Use S3 with DynamoDB locking.

terraform {
backend "s3" {
bucket         = "my-tf-state"
key            = "production/terraform.tfstate"
region         = "us-east-1"
dynamodb_table = "terraform-locks"
encrypt        = true
}
}

State Locking

DynamoDB locking prevents concurrent runs. Two engineers running Terraform simultaneously would corrupt state without locking.

Module Design

Single Responsibility

Each module does one thing. The VPC module creates networking. The RDS module creates databases. Do not mix concerns.

Variables and Outputs

Modules should accept variables for all configurable values and output all resources that other modules need.

# modules/rds/variables.tf
variable "instance_class" {
type    = string
default = "db.t3.micro"
}

variable "allocated_storage" {
type    = number
default = 20
}

modules/rds/outputs.tf
output "endpoint" {
value = aws_db_instance.main.endpoint
}

Team Workflow

Conclusion

Infrastructure as code is not optional for production systems. Terraform with proper state management, modular design, and CI integration makes infrastructure as reliable as your application code.