Infrastructure as code

Terraform plans that make infrastructure changes reviewable

Treat configuration, state, and apply approvals as a controlled workflow—automation still needs cloud judgment.

ModulesDeclarative HCL Schemas

EngineDAG Dependency Graph

StateEncrypted S3 & DynamoDB

ControlPlan-in-PR & Drift Audits

Infrastructure as Code Engine

Terraform State & Execution Studio

Declarative HashiCorp HCL Module Specifications

IaC Modules

Defining immutable, versioned infrastructure components (VPCs, clusters, IAM roles) through reusable modules with strict type validation.

Reusable HCL Module Contracts

Strict Variable Type Validation

Semver Module Version Pinning

Multi-Cloud Provider Registry

DeclarationHCL ModulesInput Contracts

Graph CoreDAG ExecutionProvider APIs

State & ControlS3 / DynamoDBAtomic Mutex Lock

Signature Technical Lab

Declarative IaC & Remote State Governance Observatory

Inspect how Digital Elliptical architects production Terraform configurations around reusable HCL modules, DAG graph dependencies, remote S3/DynamoDB state locking, and automated drift detection.

Active Terraform Spec

Modular Multi-Account VPC & Transit Gateway

Standardizing enterprise AWS VPC networking across production and staging accounts using parameterized HCL modules with Transit Gateway peering.

01. HCL Module ContractsModule Inputs

Module Invocation

module "vpc" { source = "./modules/aws-vpc", cidr = var.vpc_cidr }

Encapsulates subnets, route tables, and NAT Gateways with strict variable validation rules.

Module Rules

Inputs: vpc_cidr (string), availability_zones (list)

Validation: regex("^10\\..*", var.vpc_cidr)

Outputs: vpc_id, private_subnet_ids, nat_gateway_ips

Pinning: aws provider ~> 5.30

Semver Pinned Providers Prevent Breaking Upstream Changes

02. Dependency Graph & DAGGraph Core

Graph Execution Pattern

DAG resolves VPC -> Subnets -> InternetGateway -> RouteTables -> NAT in parallel

Implicit resource attributes pass vpc.id directly into subnet resource blocks

Lifecycle Rules

lifecycle { prevent_destroy = true } safeguards core routing tables from accidental deletion

DAG Resolves Implicit Attribute Dependencies in Parallel

03. Remote State & Mutex LockingS3 / DynamoDB

Backend Storage

Remote S3 backend in dedicated security account with AES-256 KMS encryption

State Locking EngineDynamoDB table tf-state-locks enforces atomic single-writer mutex locks

Drift & VersioningS3 Object Versioning + MFA Delete protects against state file corruption

DynamoDB State Locks Eliminate Concurrent Apply Race Conditions

Terraform Root Module & Remote State Backend Implementation ContractHashiCorp HCL Contract

Root Module (main.tf)

# 01_main.tf
module "core_network" {
  source             = "git::https://github.com/org/terraform-aws-vpc.git?ref=v2.4.0"
  environment        = var.environment
  vpc_cidr           = "10.100.0.0/16"
  availability_zones = ["us-east-1a", "us-east-1b", "us-east-1c"]
  enable_nat_gateway = true
  single_nat_gateway = var.environment == "prod" ? false : true
  tags = {
    ManagedBy = "Terraform"
    Owner     = "PlatformEngineering"
  }
}

Backend & Providers (backend.tf)

# 02_backend.tf
terraform {
  required_version = ">= 1.7.0"
  required_providers {
    aws = { source = "hashicorp/aws", version = "~> 5.35" }
  }
  backend "s3" {
    bucket         = "corp-tf-state-production"
    key            = "networking/vpc/terraform.tfstate"
    region         = "us-east-1"
    dynamodb_table = "terraform-lock-table"
    encrypt        = true
  }
}

System Architecture

Terraform Declarative IaC & State Engine Topology

A structured breakdown of how HCL modules, DAG dependency graphs, provider RPC plugins, remote state backends, and drift detection pipelines coordinate.

Configuration Input

Declarative HCL Module Plane

Defining parameterized infrastructure components using reusable HashiCorp HCL modules with explicit variable type constraints.

HCL SyntaxModule EncapsulationVariable ValidationOutput Contracts

DAG Resolver

Core Graph & Dependency Engine

Constructing and traversing a Directed Acyclic Graph (DAG) of resources to parallelize provisioning and calculate speculative plans.

Terraform CoreDAG Graph BuilderImplicit DependenciesPlan Diffs

Provider Interface

Cloud Provider Plugin RPC Ecosystem

Communicating with AWS, Google Cloud, Azure, and Kubernetes APIs via compiled Go provider plugins over local gRPC.

AWS ProviderGoogle ProviderAzureRM ProviderKubernetes / Helm

State Governance

Remote State & Mutex Locking Plane

Persisting encrypted state in remote cloud object stores with atomic DynamoDB mutex locking to prevent concurrent state corruption.

S3 / GCS Remote StateDynamoDB State LocksKMS EncryptionWorkspaces

Pipeline Operations

Change Control & Drift Auditing

Gating production applies through speculative PR reviews, automated approval workflows, and scheduled drift detection audits.

Plan-in-PR BotDrift Detection CronDetailed Exit CodesState Import

IaC Fit

When Terraform Infrastructure as Code Fits

You are provisioning multi-cloud or hybrid infrastructure across AWS, Google Cloud, Azure, and Kubernetes requiring declarative change control.
Your engineering workflow requires speculative plan diffs reviewed on GitHub pull requests before applying changes to production.
Infrastructure requires immutable, reusable modules with strict input validation, outputs, and semantic version pinning.
Teams require centralized remote state management with atomic DynamoDB mutex locks to prevent race conditions.

Boundary Analysis

When Ansible or CI/CD Automation Fits Better

You need in-guest operating system configuration, package installations, and software patching (choose Ansible).
You are automating application build and deployment pipelines (choose GitHub Actions / ArgoCD).
You are managing ad-hoc, disposable developer scripts where declarative state tracking adds unnecessary complexity.

Engineering Rigor

Terraform Production Architecture Best Practices

01. PRINCIPLE

Remote State Security

Encrypting state files at rest with cloud KMS keys, restricting bucket IAM access, and enabling object versioning to protect against state corruption.

02. PRINCIPLE

Granular Blast Radius

Decomposing infrastructure into separate state files (networking, compute, data, IAM) rather than maintaining one massive monolithic state file.

03. PRINCIPLE

Plan-in-PR Discipline

Running speculative terraform plan checks on every pull request and requiring senior engineer review before running automated apply.

04. PRINCIPLE

Automated Drift Audits

Scheduling daily CI drift detection runs to catch unauthorized manual changes made directly in cloud provider web consoles.

Next Architecture Step

Discuss Your Infrastructure as Code Strategy

Design reusable HCL modules, configure secure remote state backends with DynamoDB locking, establish plan-in-PR change pipelines, and eliminate configuration drift with our cloud architects.

Schedule Architecture Review Explore GitHub Actions CI/CD →

Terraform IaC Portfolio

Related Technical Proof & Service Capabilities

Technical FAQs

Frequently Asked Questions About Terraform Infrastructure as Code

Does Terraform eliminate the need for cloud expertise?

No. Providers encode APIs, but sound architecture, IAM, networking, and cost judgment remain human responsibilities.

Can all drift be auto-fixed safely?

No. Some drift is emergency hotfix. Triage before apply; blind auto-remediation can be harmful.