Making infrastructure as code (IaC) better: A modular and scalable approach

Infrastructure as Code (IaC) has revolutionized how we provision, manage, and scale cloud environments. But as teams adopt Terraform, Pulumi, or OpenTofu across increasingly complex stacks, the cracks begin to show: brittle modules, hidden drift, poor observability, and a lack of ethical design considerations.

This article explores how to make IaC better—not just more efficient, but more maintainable, transparent, and aligned with long-term product and privacy goals. Whether you’re building multi-cloud SaaS platforms or mentoring DevOps teams, these strategies will help you architect infrastructure that scales with clarity and purpose.

Modularize Everything (But Not Blindly)

Modularization is the cornerstone of maintainable IaC. But blindly abstracting every resource into a module can lead to over-engineering and cognitive overload.

• Group by lifecycle: Separate modules for stateless services, persistent storage, and identity/auth.
• Expose only necessary variables: Avoid leaking internal logic through overly verbose inputs.
• Use composition over inheritance: Prefer small, composable modules over deep nesting.

Instead of a monolithic vm.tf, split into:

modules/
├── compute/
│   ├── vm_linux/
│   └── vm_windows/
├── network/
│   ├── vnet/
│   └── firewall/
├── identity/
│   └── service_principal/

This structure mirrors real-world concerns and simplifies onboarding.

Embrace Immutable Infrastructure

Mutable infrastructure is a breeding ground for drift—those subtle, undocumented changes that quietly erode consistency across environments. When virtual machines or containers are manually patched after deployment, you lose the declarative guarantees that Infrastructure as Code promises. Instead, embrace immutability by baking updates into fresh images using tools like Packer integrated with CI pipelines. This ensures every deployment is reproducible and traceable. Combine this with Terraform’s create_before_destroy lifecycle setting to roll out changes without downtime. And most critically, resist the temptation to SSH into production. Instead, lean on robust observability, structured logging, and automated health checks to maintain visibility without compromising infrastructure integrity.

Terraform Tip:

lifecycle {
  create_before_destroy = true
  prevent_destroy       = false
}

This ensures safe rollouts while allowing recreation when needed.

Make State Management Explicit and Secure

Terraform state is the single source of truth—but it’s also a liability if mismanaged.

Recommendations

• Use remote backends with encryption (e.g., S3 + KMS, Azure Blob + Key Vault).
• Enable state locking to prevent race conditions.
• Version and backup state regularly.

Bonus

Use terraform show and terraform state list in CI pipelines to audit changes before apply.

Build for Observability and Debuggability

Infrastructure as Code (IaC) should be transparent—not just for the original author, but for every team member and future contributor who interacts with it. To achieve this, it’s essential to surface key information through explicit outputs, such as resource IDs, IP addresses, and endpoint URLs, making infrastructure behavior visible and traceable. Modules should be clearly annotated with README files and usage examples to guide onboarding and reuse. Additionally, logging provisioning steps using null_resource and local-exec can provide valuable insight into what happens during deployment, especially when debugging or auditing changes. This level of clarity transforms IaC from a black box into a collaborative, maintainable system.

Example

output "vm_public_ip" {
  value = azurerm_public_ip.vm.ip_address
  description = "Public IP of the VM for debugging purposes"
}

Test Your IaC Like Application Code

Treat your Terraform like code—because it is.

Tools:

• Terratest: Write Go tests to validate infrastructure behavior.
• Checkov / tfsec: Static analysis for security and compliance.
• Pre-commit hooks: Enforce formatting, linting, and validation.

Workflow:

terraform fmt -check
terraform validate
checkov -d .
go test ./test/

Integrate into CI/CD to catch issues before they hit production.

Use Versioning and Semantic Tags

Versioning isn’t just for software—it’s essential for infrastructure modules.

Tips

• Tag module releases (v1.0.0, v1.1.0) in Git.
• Use ref = "v1.0.0" in module sources.
• Document breaking changes in CHANGELOG.md.

This enables safe upgrades and rollback strategies.

Prioritize Idempotency and Predictability

Infrastructure as Code should be predictable and repeatable—producing the same outcome every time it runs, without surprises. To achieve this level of reliability, avoid using random values unless they serve a specific, intentional purpose. Be cautious with constructs like count and for_each, as improper use can lead to unintended resource deletions or re-creations. Input validation blocks are also essential, helping enforce constraints and catch misconfigurations early. Together, these practices ensure your IaC remains stable, auditable, and safe to deploy across environments.

Example

variable "region" {
  type = string
  validation {
    condition     = contains(["eastus", "westus"], var.region)
    error_message = "Region must be eastus or westus"
  }
}

Make IaC Collaborative and Documented

IaC is a team sport. Don’t let your modules become black boxes.

Tools:

• Use ADR (Architecture Decision Records) to document tradeoffs.
• Maintain module registries with usage examples.
• Encourage code reviews with clear diffs and context.

Tip:

Use terraform plan -out=tfplan and terraform show -json tfplan to generate machine-readable diffs for review.

Automate Everything (But Stay Intentional)

Automation is powerful—but it should never be blind.

Automate

• CI/CD pipelines for plan, apply, and destroy.
• Drift detection with scheduled terraform plan.
• Cost estimation with tools like Infracost.

Avoid

• Auto-apply without human review.
• Destroying resources without backups.
• Ignoring failed applies—always investigate.

Bonus: Terraform Tips for Multi-Cloud Deployments

When deploying infrastructure across multiple cloud providers like AWS, Azure, and GCP, maintaining modularity and abstraction is essential to avoid complexity and ensure scalability. Each cloud has its own syntax, resource types, and quirks, so using provider aliases allows you to cleanly separate configurations and manage them in parallel without conflicts. This is especially useful when you need to instantiate resources from different clouds within the same Terraform project.

To streamline your architecture, it’s wise to abstract common infrastructure patterns — such as virtual machines, storage buckets, or networking—into cloud-specific modules. These modules encapsulate provider-specific logic while exposing a consistent interface, making it easier to reuse and maintain code across environments. For example, you might have a vm_module that deploys EC2 instances on AWS, VMs on Azure, and Compute Engine on GCP, all driven by the same input variables.

Finally, managing state is critical in multi-cloud setups. Using Terraform workspaces or separate state files per environment (e.g., dev, staging, prod) helps isolate deployments, prevent accidental overwrites, and support environment-specific configurations. This separation also improves collaboration and CI/CD workflows by reducing the risk of state file contention.

Together, these strategies create a clean, scalable foundation for multi-cloud IaC that’s easier to test, extend, and secure.

Example:

provider "aws" {
  alias  = "us"
  region = "us-east-1"
}

provider "aws" {
  alias  = "eu"
  region = "eu-west-1"
}

Conclusion

Making Infrastructure as Code better isn’t just about writing cleaner HCL—it’s about designing systems that scale, empower teams, and respect users. By embracing modularity, observability, ethical design, and collaborative workflows, you can build infrastructure that’s not just functional, but foundational.

Whether you’re deploying privacy-first SaaS platforms or mentoring DevOps teams, these principles will help you architect with clarity, confidence, and impact.

Related Posts

• The Diverging Paths of Infrastructure as Code: How OpenTofu Handles State Management Differently from Terraform
• The Essential Guide to Docker for Packaging and Deploying Microservices
• Understanding OpenTofu config files
• What are the different files used by Terraform?
• How Infrastructure as Code delivers unprecedented time savings
• ClickOps vs. IaC: Why Terraform wins in the modern cloud era
• What is Terraform?
• Deploy Azure like a pro: your first Terraform main.tf made simple
• The function of the main.tf file
• Why developers are moving away from Terraform—and what they're choosing instead
• What is OpenTofu? Terraform’s open-source alternative

Adam Lloyd-Jones

Adam is a privacy-first SaaS builder, technical educator, and automation strategist. He leads modular infrastructure projects across AWS, Azure, and GCP, blending deep cloud expertise with ethical marketing and content strategy.

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