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What is Infrastructure as Code (IaC)?
5 min. read
Table of contents
Infrastructure as code (IaC) refers to the technology and processes used to manage and provision infrastructure with machine-readable languages (code) instead of manual operations.
IaC was first introduced around 2009 by DevOps company Puppet and is the foundation for several other companies and technologies such as Ansible, Chef, Salt, and more. In recent years, however, IaC popularity has been driven by Terraform, the open-source framework by HashiCorp. More than any other framework, Terraform has made infrastructure as code limitlessly customizable and accessible and has paved the way for the surrounding IaC ecosystem. The community surrounding Terraform is also notable for its contributions of ready-built modules.
Simultaneously, cloud providers have created their own configuration frameworks to help simplify and automate infrastructure orchestration and management. AWS CloudFormation, Azure Resource Manager, and Google’s Cloud Deployment Manager all make it easier for infrastructure engineers to build repeatable environments.
While each specific framework has its own conventions and configuration syntax, IaC is generally made up of resource declarations, input variables, output values, configuration settings, and other parameters. IaC contains all the configuration needed to spin up infrastructure, networking, load balancing, and IAM.
Benefits of IaC
By using automation and predictability, IaC makes cloud provisioning and management easier overall, with several cost- and performance-related benefits.
IaC simplifies cloud provisioning by templatizing all manual configurations with automation, enabling engineers to spin up new infrastructure incredibly quickly. That speed results in incredible scalability, making it easy to apply one template to exponential VMs or resources and cost savings, allowing engineers to spend less time performing repetitive, manual provisioning work. With IaC, it’s also much easier to de-provision infrastructure when it’s not in use, decreasing overall computing costs and maintenance expenses.
Because with IaC all compute, storage, and networking services are deployed the same way every time, you can maintain consistency across resources and even across multi-cloud environments. That consistency puts human-error at a minimum and has the potential for incredibly complete versioning and logging.
IaC also encourages collaboration between developers and operators. By provisioning cloud resources across environments and clouds with a unified, common language, you can easily stay on the same page between teams.
Challenges of IaC
As with any emerging technology, IaC comes with its own drawbacks, mostly related to the lack of cohesive awareness and added complexity.
Because it is relatively new, the biggest challenge IaC presents is related to understanding its intended use and embracing it fully. There is undoubtedly a learning curve to adopting IaC, which is at odds with manual infrastructure provisioning—by design. Replacing established processes and technologies can be disruptive.
Because it can also run in parallel to manual cloud orchestration, implementing IaC without full visibility and collaboration can lead to confusion as to how and where resources are provisioned. When fully embraced, its immutable nature means that instead of troubleshooting and fixing deployed resources, you simply re-provision it. When manual changes are made to IaC-provisioned resources, you lose that immutability and introduce risk of damaging services or introducing unintended behaviors.
As is the case when adding any new technology to already complex infrastructure stacks, IaC can introduce risk. Confusion and risk are only exacerbated when several frameworks are in use across teams, as is common within larger organizations.
Infrastructure as Code FAQs
Declarative infrastructure as code defines the desired state of the infrastructure without specifying the steps to achieve it. Tools like Terraform and AWS CloudFormation use this approach. Users describe resources, configurations, and dependencies in a high-level language. The IaC tool then interprets this desired state and manages the underlying infrastructure to match it.
Declarative IaC ensures consistency, repeatability, and reduces configuration drift. It abstracts the complexities of infrastructure management, allowing for easier maintenance and updates by focusing on the end state rather than the process.
Imperative IaC specifies the exact steps required to achieve the desired infrastructure state. Tools like Ansible and Chef use this approach. Users write scripts or playbooks detailing each action, such as creating resources, configuring settings, and installing software.
Imperative IaC offers fine-grained control over the infrastructure provisioning process. It allows for sequential execution and customization of tasks. While it provides flexibility, managing complex environments can become cumbersome. Combining imperative and declarative approaches can balance control and simplicity, enhancing overall infrastructure management.
Terraform is an open-source IaC tool by HashiCorp that enables the provisioning and management of cloud infrastructure using a declarative configuration language. It supports multiple cloud providers, including AWS, Azure, and Google Cloud. Terraform uses a configuration file to define resources, such as virtual machines, networks, and storage. The tool's state management feature tracks resource changes, ensuring idempotency and consistency. Terraform's modular approach allows for reusable and maintainable infrastructure code. Its robust ecosystem and provider plugins make it a versatile choice for cloud infrastructure automation.
Ansible is an open-source automation tool by Red Hat that uses an imperative approach for configuration management, application deployment, and infrastructure provisioning. It employs YAML-based playbooks to define tasks and workflows. Ansible's agentless architecture relies on SSH or WinRM for communication, simplifying deployment and management. The tool supports various modules for managing cloud resources, such as EC2 instances, S3 buckets, and Azure VMs. Ansible's declarative nature allows for idempotent operations, ensuring consistent infrastructure states. Its flexibility and ease of use make it a popular choice for automating complex IT tasks.
AWS CloudFormation is a declarative IaC service that enables the provisioning and management of AWS resources using JSON or YAML templates. Users define the desired state of their infrastructure, including compute, storage, networking, and security configurations. CloudFormation automates the deployment, updates, and management of these resources, ensuring consistency and repeatability. The service's stack concept allows for the grouping and management of related resources as a single unit. CloudFormation's integration with AWS services and support for custom resources makes it a powerful tool for automating AWS infrastructure.
Azure Resource Manager (ARM) is a declarative IaC service that enables the deployment, management, and organization of Azure resources using JSON templates. ARM templates define the desired state of resources, such as virtual machines, storage accounts, and networking components. The service ensures consistent deployment and configuration across environments. ARM provides role-based access control (RBAC) and policy enforcement for resource management. Its integration with Azure DevOps and other CI/CD tools streamlines the automation of infrastructure provisioning and lifecycle management, enhancing the efficiency of cloud operations.
Google Cloud Deployment Manager is a declarative IaC service that automates the provisioning and management of Google Cloud resources using YAML or Python configuration files. Users define the desired state of resources, such as compute instances, storage, and networking components. Deployment Manager handles the creation, update, and deletion of these resources, ensuring consistency and repeatability. The service supports templates and modules for reusable configurations. Its integration with Google Cloud services and APIs allows for seamless automation of infrastructure tasks, improving operational efficiency and reducing manual intervention.
Version control in IaC involves managing and tracking changes to configuration files and scripts using version control systems like Git. It enables collaboration among team members, ensuring that changes are documented, reviewed, and approved before deployment. Version control provides a history of modifications, allowing for rollbacks and auditing. Branching and merging strategies facilitate the development and testing of infrastructure changes in isolated environments.
Configuration drift in IaC occurs when the actual state of the infrastructure diverges from the desired state defined in the configuration files. This drift can result from manual changes, updates, or inconsistencies that are not captured by the IaC tool. Configuration drift undermines the reliability and predictability of the infrastructure, leading to potential security vulnerabilities and operational issues. Regularly applying IaC configurations and using tools like Terraform's terraform plan or AWS CloudFormation's drift detection feature helps identify and correct drift.
Idempotency in IaC ensures that applying the same configuration multiple times results in the same infrastructure state without unintended side effects.
Idempotent operations allow for consistent and repeatable deployments, reducing the risk of configuration drift and errors. Tools like Terraform and Ansible are designed to be idempotent, meaning they can detect the current state of resources and make only the necessary changes to achieve the desired state.
An IaC pipeline automates the deployment and management of infrastructure using CI/CD principles. The pipeline integrates various stages, including version control, code validation, testing, provisioning, and monitoring.
IaC pipelines enable automated testing and validation of configuration changes before applying them to production environments. This approach enhances collaboration, reduces manual intervention, and ensures that infrastructure changes are traceable, auditable, and aligned with best practice.
Policy as code in IaC involves defining and enforcing security and governance policies using code. Tools like Open Policy Agent (OPA) and HashiCorp Sentinel allow organizations to codify policies for resource configurations, access controls, and compliance requirements. These policies are integrated into the IaC pipeline, automatically evaluating configurations against predefined rules during deployment.
State management in IaC involves tracking the current state of deployed resources to ensure alignment with the desired state defined in configuration files. Tools like Terraform use state files to store information about resources, their attributes, and relationships. State management enables idempotency, allowing the IaC tool to determine necessary changes during subsequent deployments.
Provisioning in IaC involves the automated deployment and configuration of infrastructure resources using code. Tools like Terraform, Ansible, and AWS CloudFormation enable users to define infrastructure components, such as virtual machines, networks, and storage, in configuration files. The IaC tool interprets these files and orchestrates the creation and configuration of resources.
Provisioning ensures consistency, repeatability, and efficiency in deploying infrastructure. It reduces manual intervention, accelerates deployment times, and enhances scalability. Automated provisioning also supports version control, auditing, and compliance with organizational policies.
An IaC module is a reusable, self-contained unit that encapsulates a specific set of infrastructure resources and configurations. Modules enable the abstraction and modularization of complex infrastructure components, promoting code reuse and maintainability. Tools like Terraform support modules, allowing users to define and manage infrastructure as building blocks. Modules can be versioned, shared, and combined to create larger, more complex configurations. Using IaC modules enhances consistency, reduces duplication, and simplifies the management of infrastructure changes across multiple environments.
IaC testing involves validating the correctness, security, and compliance of infrastructure configurations before deployment. Testing frameworks like Terratest and InSpec enable automated testing of IaC code. Tests include syntax validation, unit tests for individual modules, integration tests for combined configurations, and security checks for compliance with policies. Continuous testing in the IaC pipeline ensures that only validated and secure configurations are deployed. IaC testing reduces the risk of errors, misconfigurations, and security vulnerabilities, enhancing the reliability and robustness of cloud infrastructure.
IaC linting involves analyzing IaC scripts to identify syntax errors, code style issues, and potential security vulnerabilities. Linting tools like TFLint for Terraform and ansible-lint for Ansible help ensure that IaC code adheres to best practices and organizational standards. Linting enhances code quality by catching common mistakes early in the development process. It supports automated checks in CI/CD pipelines, providing immediate feedback to developers. Effective linting reduces the risk of misconfigurations, improves maintainability, and ensures consistent code quality across IaC repositories.
Infrastructure orchestration in IaC automates the coordination, management, and deployment of interconnected cloud resources. Orchestration tools like Kubernetes, Terraform, and AWS CloudFormation enable the definition of complex infrastructure topologies using code. These tools handle dependencies, resource provisioning, and configuration management in a cohesive workflow.
