skills.rest
xalgord
xalgordCOMMUNITY
Explore all skills by this author →
WebsiteGitHub

implementing-policy-as-code-with-open-policy-agent

Implements OPA Gatekeeper admission control and Rego policy testing for Kubernetes and CI/CD pipelines.

954|172|Updated Mar 13, 2026
Search Tags:#kubernetes#devsecops#policy-as-code#opa#conftest#rego#Gatekeeper
One-click install
npx skills add https://github.com/xalgord/xalgorix --skill implementing-policy-as-code-with-open-policy-agent
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: implementing-policy-as-code-with-open-policy-agent
Source: https://github.com/xalgord/xalgorix/tree/main/internal/tools/skills/data/devsecops/implementing-policy-as-code-with-open-policy-agent
Command: npx skills add https://github.com/xalgord/xalgorix --skill implementing-policy-as-code-with-open-policy-agent

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Security rules enforced through manual review or documentation drift out of sync and cannot block non-compliant Kubernetes workloads or pipeline changes. This Skill provides a concrete workflow for codifying organizational policies as version-controlled, testable, and enforceable rules using Open Policy Agent and Gatekeeper.

Core Features & Use Cases

  • Kubernetes Admission Control: Deploy Gatekeeper via Helm and define ConstraintTemplates and Constraints that deny privileged containers, missing resource limits, and missing labels.
  • Local and CI Policy Testing: Validate Kubernetes manifests, Terraform, and Dockerfiles against Rego policies with conftest, wired into GitHub Actions so violations fail the pipeline.
  • Safe Rollout Guidance: Start in warn mode, remediate, then switch to deny, with verification steps that prove the webhook actually rejects violating resources.
  • Use Case: A platform team needs to stop teams from deploying privileged containers and untagged images across shared clusters. They install Gatekeeper, apply deny constraints for privileged pods and :latest tags, and add a conftest job to every pull request touching k8s/ or terraform/.

Quick Start

Install Gatekeeper with Helm, apply the provided ConstraintTemplates and deny constraints, then run conftest against a manifest using a :latest image to confirm the policy fails the check.

Frequently Asked Questions about implementing-policy-as-code-with-open-policy-agent

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I enforce security policies in Kubernetes with OPA Gatekeeper?▼

Install Gatekeeper via Helm into the gatekeeper-system namespace, then create ConstraintTemplates containing Rego policy logic and apply Constraints that set enforcementAction to deny. Verify enforcement by applying a violating Pod, such as a privileged container, and confirming the API server rejects it.

How to test Kubernetes manifests against OPA policies in CI?▼

Use conftest to run Rego policies against manifests locally or in a pipeline, for example conftest test deployment.yaml --policy policies/. In GitHub Actions, install conftest and run it over k8s/ and terraform/ paths so deny rules return a non-zero exit code and fail the job.

OPA Gatekeeper vs Kyverno for Kubernetes policy enforcement?▼

Gatekeeper uses the Rego language and CRD-based ConstraintTemplates, which suits teams needing a general-purpose policy engine reusable beyond Kubernetes. Kyverno uses YAML-based policies with no Rego required, which lowers the learning curve for Kubernetes-only use cases.

Why is my Gatekeeper constraint not blocking non-compliant pods?▼

Common causes are enforcementAction left as warn or dryrun, match.kinds omitting Deployment or StatefulSet so workloads bypass the policy, or the webhook failing open. Apply a clearly violating Pod and confirm the API server rejects it with the policy's violation message.

When should I not use OPA Gatekeeper?▼

Gatekeeper is not a vulnerability scanner, runtime threat detector, or network policy engine. Use Trivy or Checkov for vulnerability scanning, Falco for runtime detection, and Kubernetes NetworkPolicy or Calico for network segmentation.

Related Skills

Explore More Software Engineering Skills→
darellchua2darellchua2
4

opentofu-kubernetes-explorer

Provision Kubernetes infrastructure and deploy Helm charts using OpenTofu.

Community
Advanced
spigellspigell

k8s-policy

Detect Kyverno and Gatekeeper policies and inspect violation reports.

Community
Intermediate
vertivolatamvertivolatam
1

Container Security

Automate container security with image scanning, runtime monitoring, and image signing.

Official
Advanced
adaptive-enforcement-labadaptive-enforcement-lab
3

policy-as-code-template-library

Automate Kubernetes governance and security policy enforcement with Kyverno and OPA templates.

Official
Intermediate