Infrastructure as Code
Learn how Infrastructure as Code lets you define cloud resources declaratively for repeatable, version-controlled, automated provisioning.
Infrastructure as Code is a free System Design Basics for Backend Developers lesson on CoddyKit — lesson 4 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the System Design Basics for Backend Developers learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
From Clicking to Code
Manually clicking through a cloud console to create servers and networks is slow, error-prone, and impossible to reproduce. Infrastructure as Code (IaC) defines your infrastructure in files you can version, review, and re-run.
Why IaC Matters
IaC brings software engineering discipline to infrastructure:
- Version control and code review for changes
- Reproducible environments (dev, staging, prod identical)
- Automated, fast provisioning and teardown
- Self-documenting infrastructure
Declarative vs Imperative
IaC tools are usually declarative: you describe the desired end state and the tool figures out how to get there. Imperative scripts instead list the exact steps. Declarative is easier to reason about and converge to.
A Declarative Resource
Here is a declarative definition of a virtual machine. You state what should exist; the tool creates or updates it to match.
resource "aws_instance" "web" {
ami = "ami-123456"
instance_type = "t3.micro"
tags = {
Name = "web-server"
}
}Idempotency
A core IaC property is idempotency: applying the same definition repeatedly yields the same result. If the resource already matches, nothing changes. This makes re-runs safe.
State and Drift
Many tools track a state of what they manage. When reality diverges — someone changes a resource by hand — that is drift. The tool detects drift and can reconcile infrastructure back to the declared definition.
Plan Before Apply
Good IaC workflows preview changes before applying them. A plan step shows exactly what will be created, changed, or destroyed, so you catch a destructive change in review rather than in production.
$ terraform plan
+ aws_instance.web will be created
~ aws_security_group.sg will be updated
- aws_instance.old will be destroyedProvisioning vs Configuration
Two related but distinct jobs:
- Provisioning creates infrastructure (Terraform, CloudFormation, Pulumi)
- Configuration management sets up software on existing machines (Ansible, Chef, Puppet)
Containers and immutable images blur this line.
Modules and Reuse
Avoid copy-paste by packaging infrastructure into reusable modules with input variables. One well-tested module can stamp out identical, parameterized environments for many teams.
module "web" {
source = "./modules/app"
instance_type = "t3.small"
env = "production"
}IaC and Cloud-Native CI/CD
IaC fits naturally into pipelines: a commit triggers a plan, review approves it, and the pipeline applies it. Combined with containers and Kubernetes manifests, the entire stack — network, cluster, and apps — becomes reproducible from code.
Best Practices
Keep IaC healthy: store state remotely and locked, never hardcode secrets, review every plan, keep modules small, and treat infrastructure code exactly like application code — tested and reviewed.
Quick Check
Test your understanding of Infrastructure as Code.
Recap
You learned the foundations of Infrastructure as Code:
- Declarative definitions describe desired state idempotently
- State tracking detects and reconciles drift
- Plan before apply to preview changes safely
- Modules enable reuse; IaC integrates into CI/CD pipelines
Frequently asked questions
Is the “Infrastructure as Code” lesson free?
Yes — the full text of “Infrastructure as Code” is free to read here on the web, and the System Design Basics for Backend Developers course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the System Design Basics for Backend Developers course, upgrade to CoddyKit PRO.
What will I learn in “Infrastructure as Code”?
Learn how Infrastructure as Code lets you define cloud resources declaratively for repeatable, version-controlled, automated provisioning. You practise System Design Basics for Backend Developers with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start System Design Basics for Backend Developers?
No prior experience is required. System Design Basics for Backend Developers on CoddyKit is structured for beginners through advanced learners; this is — lesson 4 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “Infrastructure as Code” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this System Design Basics for Backend Developers lesson?
Yes. Every System Design Basics for Backend Developers lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.