Booting servers from a cloud console by clicks was once common practice. Nowadays, most engineering teams build all their infrastructures in code form. If you were thinking of what is Infrastructure as Code and what makes it such a crucial component in DevOps and cloud engineering nowadays, this guide contains all the necessary information about the concept itself, how it works, the tools for it, its advantages, and how you can implement it in your projects.
After finishing this guide, you will know what is Infrastructure as Code and how it has taken the place of traditional infrastructure management in most companies.
What is Infrastructure as Code? A Simple Definition
Well, then, what is Infrastructure as Code in simple terms? Infrastructure as Code, which is usually referred to as IaC, is a technique where the management and provisioning of infrastructure (servers, networks, load balancers, databases, and much more) happen using machine-readable configuration files, rather than any manual or interactive configuration tool.
Unlike an engineer who has to log into the cloud console to create a virtual machine manually through a few clicks, with IaC, the engineer can simply create a configuration file explaining what the infrastructure should be and a tool will create, modify, or delete resources to match the requirements mentioned in the file.
When asked what is Infrastructure as Code, it becomes easier to understand by imagining it as something that doesn’t just exist as manual steps performed by someone, but instead as code itself.
Why Was Infrastructure as Code Created? The Problem It Solves
To better understand Infrastructure as Code, it is necessary to consider the issues that the concept aims to address. Prior to the introduction of IaC, infrastructure was either managed manually or through a poorly documented process using runbooks.
The above-mentioned manual process resulted in a number of problems that include but not limited to:
Configuration drift – manually configured servers tended to become different from one another even though they were required to be identical due to the manual nature of the process which led to some differences every single time
Lack of documentation – the "true" configuration of the servers was stored in the engineer's head, which made it extremely problematic if that particular engineer left the company
Time-consuming provisioning process – creation of new environment manually took lots of time (hours/days)
Challenging disaster recovery – reconstruction of the infrastructure manually after a failure occurred was difficult since there was no proper documentation
Auditability – lack of traceability of changes in infrastructure
Knowing what is Infrastructure as Code means knowing how it aimed to resolve those issues.
What is Infrastructure as Code Built On? Core Principles
Most definitions of what is Infrastructure as Code are based on several key principles which make it different from the previous generation of infrastructure management.
1. Declarative vs Imperative Configuration
Most of the IaC systems work with configurations either declaratively or imperatively. In case of declarative approach (such as Terraform), it is necessary to define the desired final state of the infrastructure and then the system defines its own ways of achieving that. The imperative systems (traditional shell scripts and to some degree Ansible) require a detailed description of the whole process of getting to the desired state of the system. Most contemporary IaC systems use the declarative approach since it is more clear and easy to manage.
2. Idempotency
Idempotency is an important feature of Infrastructure as Code – running the configuration once or multiple times should give the same results without any unwanted actions being done. If the server already conforms to the described configuration, then repeating the IaC procedure should only prove that.
3. Version Control
Since infrastructure is represented with the help of code, then it can be saved together with application code in Git and tracked through the whole history.
4. Automation
Automation of tools to read the configuration files and make changes to the actual infrastructure is an essential feature of IaC that eliminates any manual error-prone tasks from the provisioning process.
These are the core principles that define Infrastructure as Code in essence – a completely new approach to how infrastructure should be designed, managed and developed.
What is Infrastructure as Code Compared to Manual Provisioning?
One of the ways to better comprehend what Infrastructure as Code is would be to make a direct comparison between the old school method of manually configuring everything via console and what Infrastructure as Code does. Configuration drift, inefficiency at scale, and lack of proper documentation is inherent to the old-fashioned way of doing things, but when it comes to Infrastructure as Code, the results are consistent and repeatable with the code itself being your documentation. Change tracking in manual infrastructure is very limited compared to the full version history offered by IaC, and not only is it hard to review and troubleshoot problems in such an infrastructure, but it will be impossible to restore anything once a problem happens.
Types of Infrastructure as Code Tools
In order to know what is Infrastructure as Code, one should learn about the various types of tools which exist, as each solves a unique problem.
Provisioning Tools
These types of tools concentrate on provisioning the actual infrastructure components, such as virtual machines, network, storage, and cloud components.
Terraform – cloud agnostic provisioning tool with declarative language HCL, supports virtually all major cloud providers
AWS CloudFormation – Amazon’s native IaC tool which provisions AWS components using JSON/YAML templates
Azure Resource Manager (ARM) Templates / Bicep – Microsoft’s native IaC tools for provisioning Azure components
Pulumi – an IaC tool which allows developers to define their infrastructure in general purpose programming languages such as Python, TypeScript, or Go
In order to know what is Infrastructure as Code, one should learn about the various types of tools which exist, as each solves a unique problem.
Provisioning Tools
These types of tools concentrate on provisioning the actual infrastructure components, such as virtual machines, network, storage, and cloud components.
Terraform – cloud agnostic provisioning tool with declarative language HCL, supports virtually all major cloud providers
AWS CloudFormation – Amazon’s native IaC tool which provisions AWS components using JSON/YAML templates
Azure Resource Manager (ARM) Templates / Bicep – Microsoft’s native IaC tools for provisioning Azure components
Pulumi – an IaC tool which allows developers to define their infrastructure in general purpose programming languages such as Python, TypeScript, or Go
Configuration Management Tools
These tools are centered around configuring and managing the software and configurations in already provisioned servers.
Ansible – an agentless configuration management tool which uses playbooks written in YAML format
Chef – configuration management tool using a domain-specific language written in Ruby, using client-server architecture
Puppet – configuration management tool written in Puppet’s own declarative language
Even though provisioning tools and configuration management tools address two separate problems, both are often used in combination in practice. For example, provisioning a virtual machine using Terraform, and then configuring the software using Ansible. In order to understand what is Infrastructure as Code in practical terms, we need to understand these two tools classes and their interaction with one another.
These tools aim at setting up and managing the software on servers already provided.
Ansible – Agentless configuration management solution utilizing playbooks written in YAML language.
Chef – Configuration management solution utilizing Ruby-based Domain Specific Language and client-server architecture.
Puppet – Another configuration management solution utilizing own declarative language and client-server architecture.
While there is a difference between provisioning and configuration management tools and they solve distinct issues, in practice many companies deploy both categories of tools. For instance, Terraform could be used to provide a virtual machine and Ansible to set up software running on it. The knowledge about what is Infrastructure as Code in practice often comes down to learning about how these two groups of tools cooperate.
A Simple Infrastructure as Code Example
To make what is Infrastructure as Code more concrete, here's a basic Terraform example that provisions a single virtual machine on AWS:
resource "aws_instance" "web_server" {
ami = "ami-0c55b159cbfafe1f0"
instance_type = "t2.micro"
tags = {
Name = "WebServer"
}
}
Instead of manually clicking through the AWS console to launch this instance, an engineer runs terraform apply, and Terraform automatically creates the resource to match this declaration. If the instance type needs to change later, the engineer simply updates the file, commits the change, and runs terraform apply again — Terraform calculates exactly what needs to change and applies only that difference.
This small example captures the essence of what is Infrastructure as Code in daily practice: infrastructure changes flow through code, not manual clicks.
Why Does Infrastructure as Code Matter? Key Benefits
Having discussed what Infrastructure as Code is, let's discuss why many companies started using Infrastructure as Code.
1. Consistency and Less Drift
As infrastructure is coded and deployed automatically, environments become consistent because there are no minor differences introduced by manual setup.
2. Fastness and Efficiency
Deployment of new environments, both for development, testing or scaling purposes, takes only several minutes because the whole process is automated.
3. Version Control and Traceability
All infrastructure updates are stored in Git and therefore there is a possibility to see what was updated and when, which brings a lot of benefits comparing to unrecorded manual updates.
4. More collaboration
Infrastructure updates can pass the same procedure as application code update (pull requests, code reviews, etc.)
5. Better Disaster Recovery
As everything is described using code, it will be possible to recreate the environment after a disaster simply by running the IaC software, instead of having to try to recreate an environment based on one’s memory or poor documentation.
6. Cost Reductions
By automating provisioning and de-provisioning processes, one will be able to create an environment only when it is necessary and destroy it after the process is done, thus saving money spent on unused infrastructure.
7. Scalability
With IaC, it will become much simpler to deploy infrastructure in various environments or locations, as the same code will be used, but with some minor differences in parameters.
Common Use Cases: What is Infrastructure as Code Used For?
Examples of how Infrastructure as Code is used in practice can help understand its application better. Such examples are:
- Cloud infrastructure provisioning – the process of setting up virtual machines, networks, storage, and managed services in such cloud providers as AWS, Azure, GCP, and others
- Multitarget configuration consistency – making sure that configurations of dev, test, and production environments are identical and avoid such problems as something works in test but not in production
- Disaster recovery and business continuity – quick and easy rebuild of the infrastructure after the outage or failure
- Kubernetes and container platform provisioning – provision clusters and infrastructure on which containerized apps will be running
- Security and compliance enforcement – coding security group rules and access policies
- Automatic CI/CD pipeline provisioning – automatically provisioning test environment and later tearing it down once the pipeline is finished
- Multi-cloud and hybrid cloud management – using Terraform and similar technologies to manage infrastructure in different clouds from a single codebase
All these are examples of different aspects of the problem which IaC solves.
Declarative vs Imperative IaC: A Deeper Look
Understanding what Infrastructure as Code actually is also implies a deeper understanding of declarative vs imperative approaches because the choice of this aspect heavily affects the way a team works with its tools.
A declarative approach implies stating the end result - "there should be three web servers running this configuration" - and letting the tool decide which actions have to be taken in order to achieve the desired end result - creating new resources, changing something in the existing infrastructure, or getting rid of unnecessary resources. Both Terraform and CloudFormation use a declarative approach.
In contrast, an imperative approach involves stating a particular sequence of commands necessary to get a certain result - "create this server, then install this package, then start this service". Although Ansible playbooks are rather declarative definitions of tasks, the approach implies executing tasks in a particular order, thus being more imperative than the state-driven model used by Terraform.
Modern teams tend to prefer declarative IaC when it comes to provisioning because of its simplicity and convenience - there is no need to think of all possible initial states and only one desired end result has to be stated.
Getting Started: How to Begin Implementing Infrastructure as Code
If you're convinced by what is Infrastructure as Code and want to start applying it, here's a practical path many teams follow:
- Start small. Pick a single, low-risk piece of infrastructure — like a development environment — and define it in code before attempting a full production migration.
- Choose a tool that fits your stack. Terraform is a strong default for cloud-agnostic provisioning, while cloud-native options like CloudFormation or ARM templates make sense if you're deeply committed to a single provider.
- Store configuration in version control. Treat your infrastructure code exactly like application code, with proper branching and pull request workflows.
- Use remote state management. For tools like Terraform, store state files remotely (not locally) so teams can collaborate safely without conflicting changes.
- Introduce code review for infrastructure changes. Require pull requests and approvals before infrastructure changes are applied, just as you would for application code.
- Integrate with CI/CD. Automate the process of validating, planning, and applying infrastructure changes as part of your existing pipelines.
- Gradually expand coverage. Migrate more of your infrastructure to code over time, rather than attempting to convert everything at once.
Best Practices for Infrastructure as Code
Once you grasp the meaning behind Infrastructure as Code, the following best practices will allow you to avoid some typical mistakes:
- Make your configurations modular. Divide complex configurations into smaller modules that can be reused instead of keeping everything in a huge single configuration file.
- Do not keep your secrets in plain text. Do not include passwords and other credentials in configuration files but use specific secret management solutions.
- Test your infrastructure changes first. Almost all IaC frameworks have "plan" or "dry-run" mode that allows you to see how the changes will be applied without any actual actions taken.
- Lock down your state files. If the tool uses state files, make sure you keep them safe and control their access because they might contain sensitive information about resources.
- Document your modules and variables. Well-named and well-documented modules and variables allow others to use your IaC more easily.
- Do not manually change resources managed with code. Any manual "click-ops" modifications of resources controlled by IaC will lead to divergence.
Challenges and Limitations of Infrastructure as Code
An important aspect of gaining knowledge regarding what is Infrastructure as Code includes being aware of the trade-offs involved. Some of these are as follows:
- Learning curve – teams used to manual approaches take some time to adapt to new software, languages, and procedures
- Complexity in managing state – the usage of state files for Terraform and similar tools creates some challenges in terms of management, particularly when working in teams
- Fragmentation of tooling – separate teams use their own tools for IaC, leading to fragmentation
- Risk of widespread problems – incorrect configuration spread to more instances will have much greater effect than in a manual approach
- Upfront investment in time – changing manually configured infrastructure to the code form requires effort beforehand
Awareness of such trade-offs is equally important to knowing what is Infrastructure as Code from a conceptual point of view.
Infrastructure as Code in DevOps and CI/CD Pipelines
Learning about Infrastructure as Code is necessary for everyone who is working with DevOps, because IaC serves as the foundation stone for most CI/CD pipelines. The changes made in infrastructure are usually validated and implemented as part of a pipeline: the pull request initiates a "plan" stage of the pipeline, which shows the changes made; a colleague verifies and approves this change, and merging this change initiates the "apply" phase of the pipeline.
The integration of IaC into CI/CD processes is also vital for the GitOps approach, when Git becomes the sole source of information not only for the application code, but for infrastructure configuration as well. In combination with configuration management tools and container orchestration platforms such as Kubernetes, IaC becomes a basis of modern cloud-based system development.
The Future of Infrastructure as Code
Going forward, there are certain trends that are influencing what is Infrastructure as Code going to be in the upcoming years:
Policy as Code – software tools for implementing policies within code, which block changes that violate policies from being implemented
AI-assisted IaC code creation – more frequent application of AI-based tools for creating, analyzing, and debugging infrastructure code
Adoption of general-purpose languages – Pulumi and other tools that allow creating infrastructure code using general-purpose programming languages are becoming increasingly popular in addition to domain-specific languages like HCL used by Terraform
Greater integration with Platform Engineering – IaC is being used more often to implement internal development platforms and self-service infrastructure management portals, thus hiding complexity from developers
Efforts to standardize the field – as the field develops, one can expect greater uniformity of approaches
All of these trends indicate that knowing what is Infrastructure as Code today will be important in the future.
Conclusion
But then, what really is Infrastructure as Code? It is one of the fundamental DevOps practices, which entails the replacement of tedious and error-prone infrastructure management through version control and automation of code. This practice brings about the same advantages that software engineers have enjoyed for many years due to the use of code-based practices. With increasing complexity of cloud infrastructures, it has become necessary for any individual involved in DevOps, cloud engineering or platform engineering to know what is Infrastructure as Code. If you would like to learn how to create your own Terraform, Ansible, CI/CD and cloud infrastructure projects based on the concepts of what is Infrastructure as Code, you may check out the DevOps Course.
Frequently Asked Questions About Infrastructure as Code
What is Infrastructure as Code in one sentence?
What is Infrastructure as Code, simply put: it's the practice of managing and provisioning infrastructure through machine-readable configuration files rather than manual processes, enabling consistent, version-controlled, and automated infrastructure management.
What is Infrastructure as Code used for most commonly?
Infrastructure as Code is most commonly used for provisioning cloud infrastructure, maintaining consistency across development, staging, and production environments, and enabling fast, reliable disaster recovery.
What is the difference between Infrastructure as Code and configuration management?
Infrastructure as Code (provisioning tools like Terraform) focuses on creating and managing the underlying infrastructure resources themselves, while configuration management tools (like Ansible or Chef) focus on configuring the software and settings on top of already-provisioned servers. Many teams use both together.
Do I need to know how to code to use Infrastructure as Code tools?
Most IaC tools use relatively approachable, declarative configuration languages (like Terraform's HCL or YAML for Ansible) rather than requiring deep general-purpose programming knowledge, though some tools like Pulumi do let you use full programming languages if preferred.
What is the most popular Infrastructure as Code tool?
Terraform is widely regarded as the most popular cloud-agnostic Infrastructure as Code tool, thanks to its broad provider support, large community, and mature ecosystem, though cloud-native options like AWS CloudFormation remain popular for teams fully committed to a single cloud provider.
