Policy as Code Basics

Policy as Code in DevOps helps teams write rules as code and check them automatically in pull requests, CI/CD, and Kubernetes. This catches problems early and keeps releases safe and fast. It also improves compliance and audits because the same rules run every time and changes are tracked in Git.

What is Policy as Code in DevOps

Policy as Code means teams write rules in files and enforce them with a policy engine during builds and deploys. Common rules include no public storage, require encryption, and do not use latest tag for images. The engine reads inputs and returns allow or deny so checks are consistent and automatic. Storing policies in Git allows reviews, tests, and version history which improves quality and reduces manual errors.

Why it matters for teams

• Faster feedback. Pipelines show clear messages when a change breaks a rule so fixes happen sooner.
• Safer by default. The same guardrails run in dev, staging, and production which reduces drift and risky surprises.
• Easier compliance. Policies can align with standards and Git history becomes the audit trail.

Policy as Code versus Infrastructure as Code

• Purpose. Infrastructure as Code builds and configures resources like networks, clusters, and databases. Policy as Code sets the rules those resources and changes must follow.
• When it runs. Infrastructure as Code runs to create or update infrastructure. Policy as Code runs in pull request checks, in CI and CD gates, and in cluster admission to approve or block changes.
• How they work together. Policy as Code is the guardrail and Infrastructure as Code is the builder. Together they enable safe and scalable automation. 

  

Where Policy as Code runs

• Pull requests. Scan infrastructure and Kubernetes files and fail the PR when a rule is broken to give early feedback.
• CI and CD gates. Add a policy check stage before deployment to stop risky changes and show clear fixes.
• Kubernetes admission. Prevent non-compliant workloads from entering the cluster to keep clusters safe by default.

Common starter rules for beginners

• Containers. Block images tagged latest, require approved registries, and deny privileged pods for safer and repeatable builds.
• Cloud. Require encryption at rest, block 0.0.0.0/0 inbound, and enforce HTTPS only for storage to reduce risk quickly.
• Operations. Require resource requests and limits, enforce naming and tagging, and add labels for ownership to improve reliability and cost control.

Beginner friendly tools

• Open Policy Agent with Rego. Flexible engine across services, infrastructure, and Kubernetes for central policy and admission control.
• Kyverno. Kubernetes native and YAML based for cluster validation, mutation, and generation.
• Checkov. Static analysis for Terraform and Kubernetes for quick pull request checks and early signal.

Quick start plan in seven days

• Day one and two. Choose a small set of clear rules. Start with encryption, public access, and image tags. Write helpful messages.
• Day three and four. Add pull request checks with infrastructure scanning. Block only high severity at first.
• Day five. Try a policy engine in a non-production cluster in dry-run or warn mode. Tune noise and messages.
• Day six. Add unit tests for policies and run them in CI to prevent regressions.
• Day seven. Enforce a few low risk rules and use time-bound exceptions with clear owners.

Example policy: no latest tag

Goal. Use fixed image tags so builds are repeatable and images are scanned.
Checkpoints. Scan pull requests for manifests, check images in CI, and deny at admission if latest is used. This keeps the rule strong end to end.

FAQ for beginners

What is Policy as Code in simple terms?
It is rules written as code that run automatically in pull requests, pipelines, and clusters to keep systems safe and compliant.

How is Policy as Code different from Infrastructure as Code?
Infrastructure as Code builds the infrastructure. Policy as Code enforces the rules that changes must follow. They work together.

Which tools should beginners use?
Start with pull request scans, then add a policy engine for admission control.

How do we avoid blocking deployments?
Start in warn or dry-run, then enforce gradually as messages and severities are tuned.

Ready to get started?

DoneDeploy builds reliable software for real world operations. Policy as Code is one of the ways teams can keep speed and safety together. Start small with a few clear rules. As those rules prove helpful, expand step by step to cover more of the pipeline and platform.