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Embracing Drift: How Infrastructure as Code (IaC) Handles Change and Evolution



Introduction

In the rapidly evolving landscape of cloud computing, Infrastructure as Code (IaC) has become a cornerstone of modern DevOps practices. It allows teams to define and manage infrastructure through code, offering consistency, repeatability, and automation. However, as systems evolve, one challenge that inevitably arises is "drift."

What is Drift in IaC?

Drift occurs when the actual state of the infrastructure diverges from the desired state as defined in the code. This can happen for various reasons—manual changes made directly in the cloud console, updates applied without going through the IaC pipeline, or even unintended consequences of automated processes. Drift can lead to discrepancies between what your IaC scripts describe and what actually exists in your environment, potentially causing issues in deployments, performance, and security.

The Impact of Drift

Drift can be particularly problematic in environments where consistency and reliability are critical. When the infrastructure drifts from its code-defined state, it can lead to unpredictable behavior, making it difficult to diagnose issues or maintain a stable environment. In highly regulated industries, drift can also mean non-compliance with industry standards, which can have serious legal and financial implications.

Detecting Drift

Detecting drift is a critical first step in managing it. Many IaC tools, like Terraform, offer built-in mechanisms to detect drift. By running a terraform plan, for example, you can compare the current state of your infrastructure against the desired state as defined in your code. If any differences are found, the plan will highlight them, allowing you to take corrective action.

Managing and Correcting Drift

Once drift is detected, the next step is to decide how to manage it. In some cases, it might be appropriate to update your IaC code to reflect the changes made manually, especially if those changes were necessary and intentional. In other cases, you might want to correct the drift by applying your IaC code again, forcing the infrastructure to revert to the desired state.

Automating drift correction can also be an option, although it requires careful consideration. Automatically correcting drift without human oversight can lead to unintended consequences, especially if the drift was caused by a necessary and legitimate change that wasn’t yet reflected in the code.

Preventing Drift

While drift detection and correction are important, preventing drift in the first place is even better. This can be achieved by:

  1. Strict Enforcement of IaC Practices: Ensure that all infrastructure changes go through the IaC pipeline, avoiding manual changes as much as possible.

  2. Regular Audits and Monitoring: Regularly audit your infrastructure and monitor for changes that occur outside of the IaC pipeline.

  3. Education and Awareness: Make sure all team members understand the importance of using IaC and the risks associated with manual changes.

  4. Automation and Integration: Integrate your IaC tools with your CI/CD pipeline to ensure that changes are automatically reflected in your infrastructure.