GitOps — Practical Implementation Guide

Introduction

GitOps applies software engineering practices to infrastructure: Git is the source of truth, and automated controllers reconcile the desired state. A practical implementation requires more than just committing manifests; it demands policy controls, promotion workflows, and drift detection.

Repository Structure

A scalable layout separates application source from deployment definitions:

• apps/ for application manifests or Helm charts.
• clusters/ for environment-specific overlays.
• policies/ for security and compliance rules.

This separation allows application teams to work independently while platform teams control environment policy.

Promotion Workflow

Promotions should be a Git operation, not an imperative command. Use pull requests to promote a version through environments.

Recommended flow:

1. CI builds an artifact and updates the staging overlay.
2. GitOps controller syncs staging and validates health.
3. Promotion PR updates the production overlay with the same artifact tag.

Drift Detection and Enforcement

Controllers should continuously detect drift between desired and actual state. When drift occurs, either reconcile automatically or generate alerts.

A Python validation step can enforce that only approved images are deployed.

import re
import sys

image = sys.argv[1]

if not re.match(r"^registry\.example\.com/.*:v\d+\.\d+\.\d+$", image):
    raise SystemExit("Image tag does not follow semantic version policy.")

print("Image tag validated.")

Use this validation in CI to block mis-tagged promotions.

Secrets and Configuration

Never store secrets directly in Git. Use sealed secrets, external secret operators, or workload identities. Treat secrets as runtime dependencies, not versioned content.

Operational Considerations

• Enable sync waves to control dependency order.
• Set automated rollback rules when health checks fail.
• Collect telemetry on reconciliation drift and sync errors.

Summary

GitOps succeeds when Git is the only path to change and the automation enforcing it is observable, policy-driven, and secure. Treat GitOps as a system of controls rather than just a deployment mechanism.