Infrastructure as Code: Benefits, Tools & Best Practices

What is Infrastructure as Code?

Infrastructure as Code (IaC) is a practice that treats infrastructure like software, using code to define and manage IT resources. Instead of manually configuring hardware and software, IaC uses machine-readable definition files to provision and manage resources, enabling automation, consistency, and scalability. 

Using declarative or imperative syntax, teams define the desired state of their environments in configuration files. These files are then executed by IaC tools, which interact with cloud provider APIs to provision and manage resources. Key concepts of IaC include definition files, automation, consistency, scalability, and version control.

Benefits of IaC include: 

• Reduced errors: Automating infrastructure management minimizes manual errors. 
• Faster deployment: IaC speeds up the deployment process by automating infrastructure provisioning. 
• Improved consistency: Consistent infrastructure across different environments improves reliability and reduces troubleshooting efforts. 
• Increased collaboration: IaC enables developers and operations teams to collaborate more effectively by using a common language (code). 
• Cost savings: Automation can lead to cost savings by optimizing resource utilization and reducing manual labor. 
• Enhanced security: IaC can enforce security policies and best practices by baking them into the infrastructure code. 
• Better auditability: Version control and code review workflows make it easier to track changes and audit infrastructure deployments. 
• Minimized risk: Codifying infrastructure reduces uncertainty by ensuring environments are predictable and reproducible.
• Single source of truth: Configuration files act as the authoritative reference for all infrastructure states, eliminating drift between environments.

Examples of IaC in action: 

• CloudFormation (AWS): A service that allows users to define and provision AWS resources using templates. 
• Terraform: A tool that enables users to define and provision infrastructure across multiple cloud providers and on-premises environments. 
• Azure Resource Manager (ARM): A service for managing Azure resources using declarative templates. 
• Ansible: An automation tool that can be used to manage infrastructure and automate tasks, including provisioning and configuration. 
• Pulumi: A tool that allows users to define infrastructure using familiar programming languages like Python, Go, and TypeScript. 
• Puppet: A configuration management tool that automates infrastructure provisioning and enforces desired system states across servers.
• Chef: A tool that uses code to automate infrastructure configuration, deployment, and management, ideal for complex, multi-tier environments. 

Infrastructure as Code benefits

IaC promises a number of benefits, including the following:

• Reduced errors: IaC reduces human intervention by codifying infrastructure setup, minimizing typos, missed steps, and misconfigurations during deployments.
• Faster deployment: By automating the setup of environments, IaC eliminates human error and ensures that infrastructure is deployed the same way every time. This accelerates deployment cycles and reduces downtime caused by misconfigurations.
• Improved consistency: Using the same code to provision environments ensures they are identical across development, testing, and production.
• Increased collaboration: Storing infrastructure as code in version control allows developers and operations teams to work together using pull requests and reviews.
• Cost savings: IaC reduces the need for manual labor and minimizes the risk of expensive errors or over-provisioned resources. Automated provisioning and deprovisioning also help ensure cloud environments are only live when needed.
• Enhanced security: Security checks can be embedded directly in code, enabling teams to enforce compliance and catch vulnerabilities early in the pipeline.
• Better auditability: Version-controlled infrastructure makes it easy to trace, review, and roll back changes for compliance and troubleshooting.
• Minimized risk: Automated, version-controlled infrastructure limits configuration drift and makes it easy to roll back to previous states. This helps teams detect and resolve issues faster, lowering the risk of outages and compliance violations.
• Single source of truth: All infrastructure definitions are stored as code in a centralized repository, making configurations transparent, auditable, and easy to manage. This supports collaboration and simplifies change tracking across teams. 

How does Infrastructure as Code work?

Infrastructure as code works by defining infrastructure configurations in human-readable code files, typically using declarative or imperative syntax. These configurations are then interpreted by IaC tools, which provision and manage the required infrastructure resources automatically.

Declarative vs. imperative approaches

• Declarative IaC specifies what the desired state of the infrastructure should be. The tool figures out the steps to reach that state. Examples include Terraform and AWS CloudFormation.
• Imperative IaC describes how to achieve the desired infrastructure setup, step by step. Tools like Ansible and Chef often follow this approach.

Key components

1. Definition files: IaC uses configuration files (often in formats like JSON or YAML) to describe the desired state of the infrastructure. 
2. Automation: IaC automates the provisioning and management of infrastructure, reducing manual effort and errors. 
3. Consistency: IaC ensures consistency across different environments (development, testing, production) by using the same code for all deployments. 
4. Scalability: IaC makes it easier to scale infrastructure up or down by simply modifying the code and redeploying. 
5. Version control: IaC integrates with version control systems (like Git), allowing for tracking changes, collaboration, and rollbacks.

Workflow example

1. A developer writes infrastructure definitions in a config file.
2. The file is committed to a version-controlled repository.
3. A CI/CD pipeline triggers the IaC tool to apply the configuration.
4. The cloud environment is provisioned or updated based on the defined state.

This process ensures that infrastructure changes are repeatable, testable, and traceable, aligning development and operations under a unified, automated workflow.

Immutable infrastructure vs. mutable infrastructure

Immutable infrastructure refers to a paradigm where components, once deployed, are never modified. Any updates require a new version of the component to be created and deployed, replacing the old one. This approach ensures consistency and eliminates configuration drift, as every change results in a clean, predictable environment.

Mutable infrastructure allows updates to be made to existing components after deployment. While this approach can be more flexible and faster for small changes, it increases the risk of inconsistencies across environments and makes debugging more difficult due to unpredictable state changes over time.

With IaC, immutable infrastructure is often preferred, as it aligns with the practice of treating infrastructure definitions as version-controlled code. It facilitates safer rollbacks, clearer change histories, and more reproducible environments, especially in CI/CD pipelines. However, certain operational tasks or legacy systems may still require mutable strategies, so teams must choose based on their use case.

What is the role of IaC in DevOps?

Infrastructure as code plays a central role in DevOps by bridging the gap between software development and IT operations through automation, collaboration, and consistency. It allows teams to manage infrastructure in the same way they manage application code, using practices like version control, peer review, and automated testing:

• Enabling continuous delivery: IaC allows infrastructure to be provisioned and configured automatically as part of the CI/CD pipeline. This means environments can be spun up and torn down quickly and reliably for testing, staging, or production, enabling faster and more frequent deployments without manual intervention.
• Reducing configuration drift: By enforcing consistent, versioned infrastructure configurations, IaC helps prevent configuration drift — a common problem in environments that are updated manually. With IaC, every change is documented and reproducible, making environments more stable and reducing bugs caused by inconsistencies.
• Supporting collaboration and transparency: Storing infrastructure code in shared version control systems (like Git) fosters collaboration between developers and operations teams. Changes are transparent, auditable, and traceable, enabling better teamwork and simplifying reviews and audits.
• Enhancing disaster recovery and scaling: IaC scripts can be reused to rebuild infrastructure in a disaster recovery scenario or to replicate environments for scaling across regions or availability zones. This ensures business continuity and supports growth without the complexity of manual configurations.
• Promoting shift-left practices: With IaC, infrastructure provisioning becomes part of the early stages of development. Developers can create and test infrastructure alongside application code, identify issues sooner, and deploy more confidently, aligning with shift-left principles in DevOps.

Infrastructure as Code security

While IaC boosts efficiency overall, it can also amplify mistakes. By moving so quickly, a minor error by a DevOps admin at the template level can be propagated across an organization’s entire cloud infrastructure. For this reason, IaC security must be implemented to reduce cloud security risk. 

IaC security solutions vary from traditional Appsec testing tools to managing policies and IaC templates. Because developers far outnumber security professionals, security needs to be shifted left to as early in the development life cycle as possible. 

Developers need an IaC security solution that allows them to consistently apply security best practices across the SDLC to reduce potential security misconfigurations and vulnerabilities from being deployed to production environments. 

IaC security should also encompass who is and who is not allowed to run scripts as well as limiting the permissions of IaC users. The principle of least privilege, in which users are given the absolute minimum levels of access required to perform their job functions, applies here and is an important part of IaC.

Challenges and limitations of IaC

While infrastructure as code offers significant automation and consistency benefits, it also introduces several challenges that organizations must address to fully realize its potential.

• Complexity and learning curve: IaC requires understanding both the infrastructure and the tools used to define it. Teams must learn domain-specific languages (DSLs), tool-specific behaviors, and cloud provider APIs. This learning curve can slow down adoption and increase the risk of misconfiguration if not carefully managed.
• Tooling fragmentation: There is no single standard for IaC. Different tools use different syntaxes and operate in different ways. Organizations may end up using multiple IaC tools across teams or projects, leading to inconsistency and difficulty in standardization and maintenance.
• State management: IaC tools must track the current state of infrastructure to apply changes accurately. Managing this state—especially in collaborative or multi-cloud environments—can be complex. Mistakes in state handling can lead to drift or unintended infrastructure changes.
• Security risks: As mentioned above, IaC templates can expose sensitive information such as credentials, API keys, or access permissions if not properly managed. Without strict access controls, versioning policies, and secret management practices, IaC files can become a security liability.
• Testing and validation: Unlike application code, infrastructure code is harder to test. There is no universal framework for IaC testing, and errors often surface only after deployment. Teams need to implement robust testing strategies using tools like policy-as-code frameworks (e.g., Open Policy Agent, Checkov) and dry-run capabilities to catch issues early.
• Cost overruns: IaC simplifies provisioning, but that ease can lead to over-provisioning or unused resources if not monitored. Without governance controls, teams may inadvertently increase cloud spend due to misconfigured or forgotten infrastructure components.
• Collaboration and governance: As infrastructure becomes code, collaboration challenges arise—especially around version control, code reviews, and approvals. Without clear policies and enforcement mechanisms, IaC changes may bypass critical checks, leading to operational issues.

Infrastructure as Code best practices

Deploying an IaC tool is the first step toward streamlining your deployment workflows. To ensure the success of your implementation, the following best practices can help:

• Track versions of IaC definitions – Storing IaC files in a version control system allows you to keep track of how your IaC definitions have changed over time. Plus, you can revert back to earlier versions if necessary.
• Adopt an immutable infrastructure – IaC is more reliable when IaC templates are used to create new resources from scratch whenever a major update is required. This minimizes the risk of creating configuration conflicts or experiencing configuration drift.
• Continuously test, integrate, and deploy – In the end, IaC is code, and like any code, it should be continuously tested to surface errors and inconsistencies before being deployed to production.
• Avoid IaC security risks – In order to configure resources, IaC tools need access to passwords and encryption keys. Don’t include these secrets in IaC definitions where they can be easily read. Best practice is to store sensitive data inside a secrets manager, so that it is secure and accessed by IaC tools only when needed.

Infrastructure as Code and DevOps success

The promise of IaC is in its ability to standardize all cloud configuration processes to maximize efficiency and minimize costs. Automation of infrastructure is now a major requirement for all organizations. As modern applications move more and more to the cloud, IaC will take on even greater importance.

When selecting an IaC tool, always keep security top of mind. Look for solutions that help organizations secure IaC templates and check for security issues, compliance violations, and other misconfigurations. The best solutions are those that allow developers to detect, track, and fix the misconfigurations as part of their normal workflow without leaving their code repositories to view results or set up a separate workflow to scan. A solution that puts security first gives security admins the confidence they need in IaC built and operated by DevOps.