GitOps Your Terraform or OpenTofu

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GitOps and Terraform are powerful tools for managing infrastructure as code. By combining these approaches, organizations can achieve automated, version-controlled, and collaborative infrastructure management. This article outlines a four-step process to implement GitOps with Terraform, enabling teams to streamline their workflows, improve consistency, and enhance the reliability of their infrastructure deployments across various environments.

Leverage GitOps For Your Terraform or OpenTofu

As DevOps has taken hold in the software development, infrastructure management has become a critical aspect of software development. We need cloud infrastructure to be agile and dependable. To meet these, two powerful concepts have emerged: GitOps and Infrastructure-as-Code (IaC). When combined, these approaches create a robust framework for managing infrastructure as code. This article will explore how to implement GitOps with the IaC tool Terraform\OpenTofu, providing you with a streamlined approach to infrastructure management.

What Is Terraform?

Terraform is an open-source infrastructure as code (IaC) tool created by HashiCorp. It allows developers and operations teams to define and provision infrastructure using a declarative language. With Terraform, you can describe your desired infrastructure state in configuration files, and the tool will handle the complexities of creating, modifying, and deleting resources across various cloud providers and services.

Terraform's power lies in its ability to manage complex infrastructure setups with consistency and repeatability. It supports a wide range of providers, from major cloud platforms to more specialized services. This versatility makes Terraform a go-to choice for organizations looking to standardize their infrastructure management across multiple environments.

What Is OpenTofu?

OpenTofu is an open-source infrastructure as code tool that emerged as a community-driven fork of Terraform. It was created in response to HashiCorp's decision to change Terraform's license from open-source to a more restrictive one. OpenTofu aims to maintain the functionality and compatibility of Terraform while remaining fully open-source.

Key points about OpenTofu:

Compatibility: OpenTofu is designed to be fully compatible with Terraform, allowing users to seamlessly transition their existing Terraform configurations and workflows.
Community-driven: It's maintained by the Linux Foundation, ensuring continued open-source development and community contribution.
Familiar syntax: OpenTofu uses the same HashiCorp Configuration Language (HCL) as Terraform, making it easy for Terraform users to adopt.
Provider ecosystem: It supports the same providers as Terraform, maintaining access to a wide range of cloud and service integrations.

OpenTofu vs. Terraform in GitOps

When implementing GitOps for infrastructure as code, OpenTofu can be used as a drop-in replacement for Terraform in most scenarios. The choice between OpenTofu and Terraform often comes down to licensing preferences and organizational requirements. Both tools can be effectively used within a GitOps workflow, leveraging the same principles of version control, declarative configurations, and automated deployments.

For organizations concerned about potential future licensing changes or those preferring a community-driven open-source solution, OpenTofu provides a viable alternative that integrates seamlessly into existing GitOps practices. Harness is sponsor of the OpenTofu project and believes you should use OpenTofu over Terraform.

What Is GitOps?

GitOps is an operational framework that takes DevOps best practices used for application development and applies them to infrastructure automation. At its core, GitOps uses Git repositories as the single source of truth for declarative infrastructure and applications. This approach leverages Git's version control capabilities to manage infrastructure changes, providing a clear audit trail and facilitating collaboration among team members.

In a GitOps workflow, any change to the infrastructure is made through a Git repository. Automated processes then sync these changes with the actual infrastructure, ensuring that the deployed state always matches the desired state defined in the repository. This method enhances transparency, improves security, and streamlines the change management process.

Why Use GitOps for Terraform??

Combining Terraform with GitOps creates a powerful synergy for infrastructure management. Here's why this pairing is particularly effective:

Declarative Nature: Both GitOps and Terraform embrace a declarative approach. You specify the desired end state, and the tools handle the implementation details.
Version Control: Terraform configurations can be easily stored in Git repositories, aligning perfectly with GitOps principles.
Automation Friendly: Terraform's command-line interface makes it ideal for integration with CI/CD pipelines, a key component of GitOps workflows.
State Management: Terraform's state files provide a clear picture of the current infrastructure, which can be compared against the desired state defined in Git.
Modularity: Terraform's module system allows for reusable, composable infrastructure components, making it easier to manage complex setups through GitOps practices.

By leveraging Terraform within a GitOps framework, organizations can achieve a high degree of automation, consistency, and traceability in their infrastructure management processes. This combination is particularly powerful when used with platforms like Harness Software Delivery Platform, which provides robust GitOps capabilities for both applications and infrastructure as code management.

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4 Steps to Use GitOps for Terraform or OpenTofu

Implementing GitOps for your infrastructure involves several key steps.

Let's break down the process into four manageable parts.

Set Up a Git Repository to Store Your Terraform Code

The first step in GitOps-ing your IaC is to set up a Git repository that will serve as the single source of truth for your infrastructure code. This repository will contain all your Terraform configuration files, modules, and associated documentation.

When setting up your repository, consider best practices such as using a clear directory structure, includ

ing comprehensive documentation, implementing branch protection rules, and using .gitignore files to prevent sensitive information from being committed.

By centralizing your Terraform code in a Git repository, you're laying the foundation for a GitOps workflow. This step also facilitates collaboration and provides a clear history of infrastructure changes.

Configure Your Infrastructure Using Terraform Code

With your repository set up, the next step is to define your infrastructure using Terraform's HashiCorp Configuration Language (HCL). This involves creating .tf files that describe your desired infrastructure state.

When writing your Terraform configurations, focus on using variables and locals for flexibility, leveraging modules for organization, following naming conventions, and generating documentation for your modules.

Platforms like Harness Infrastructure as Code Management (IaCM) can enhance this process. Harness IaCM works seamlessly with Terraform and OpenTofu, providing additional capabilities such as cost impact analysis and security scanning, which can be invaluable when making infrastructure changes.

Use Pull Requests to Manage Changes to Your Infrastructure

The third step in implementing GitOps for your Terraform setup is to establish a pull request (PR) workflow for managing infrastructure changes. This process ensures that all changes are reviewed and approved before being applied to your infrastructure.

A typical workflow involves creating branches for changes, opening pull requests, running automated checks, conducting team reviews, and merging approved changes. This approach enforces code review practices, allows for collaboration, and provides a clear audit trail of infrastructure changes.

Platforms like Harness IaCM can enhance this process by automatically running cost impact analyses and security scans on your Terraform or OpenTofu changes, updating the pull request with this valuable information. This additional context can help reviewers make more informed decisions about proposed infrastructure changes.

In conclusion, implementing GitOps for your Terraform-managed infrastructure is a powerful approach that can significantly improve your infrastructure management practices. By following these four steps - setting up a Git repository, configuring your infrastructure as code, creating an automated pipeline, and implementing a pull request workflow - you can achieve a more consistent, transparent, and efficient infrastructure management process.

The combination of GitOps and Terraform, especially when enhanced by platforms like Harness, provides a robust framework for managing infrastructure at scale. It enables teams to apply software development best practices to infrastructure management, resulting in more reliable, secure, and agile infrastructure deployments.

As you embark on your GitOps journey with Terraform, remember that the key to success lies in embracing the principles of automation, version control, and continuous improvement. With these practices in place, you'll be well-equipped to handle the challenges of modern infrastructure management in an increasingly complex technological landscape.

Create a Pipeline That Uses Terraform to Apply Changes to Your Infrastructure

The final step involves setting up a CI/CD pipeline that will automatically apply your Terraform changes to your infrastructure. This pipeline is the core of your GitOps workflow, ensuring that any changes pushed to your Git repository are reflected in your actual infrastructure.

Your pipeline should include steps to checkout the latest code, initialize Terraform, generate a plan, and apply changes. Pipelines can seem counter-intuitive for a GitOps flow. It's common to ask, "But shouldn't we just do a pull request and apply the approved change?" However, pipeline automation can help inform that pull request. By running the Terraform Plan as well as security and cost checks before the PR is approved, the PR can be decorated with additional information making it easier for the reviewer to make the right decision.

Many IaCM tools will have some support for automation tied to changes in Git, and many CI/CD tools will be able to script some IaCM behaviors. Tools like Harness are nice because they bring the pipeline maturity of a leading CI/CD tool together with the dedicated IaCM steps as well as state management typically only found in tools that specialize in infrastructure.