Q44: Terraform Modules, Multi-Environment Architecture, and Automated Configuration Drift Detection. - DevOps & Kubernetes (50 Qs)

Scaling Terraform in Enterprise Organizations

As infrastructure expands, monolithic Terraform codebases become slow and risky. Platform engineering teams structure infrastructure using reusable Modules and isolated environment folders.

php

Root Repository Directory Structure:
├── modules/
│   ├── vpc/             # Reusable module
│   └── eks_cluster/     # Reusable module
└── environments/
    ├── dev/             # Isolated backend & state
    │   └── main.tf      # Calls modules with dev variables
    └── prod/            # Isolated backend & state (Requires separate IAM role)
        └── main.tf      # Calls modules with prod variables

Detecting Configuration Drift

Drift occurs when engineers manually tweak cloud settings in the AWS/GCP Console without updating Terraform code.

bash

# Run hourly in CI to catch out-of-band manual console edits:
# -detailed-exitcode returns exit code 2 if drift is detected
terraform plan -detailed-exitcode -no-color || exit_code=$?
if [ $exit_code -eq 2 ]; then
  echo "CRITICAL: Infrastructure drift detected between code and cloud!"
  # Trigger Slack notification or automatically create Jira ticket
fi

Importing Existing Cloud Resources

When inheriting unmanaged legacy infrastructure:

hcl

# Modern Terraform 1.5+ declarative import block
import {
  to = aws_s3_bucket.legacy_data
  id = "my-existing-production-bucket-name"
}