Kyverno: Kubernetes-Native Policy Management Made Simple

Managing security and compliance in Kubernetes is essential. While Open Policy Agent (OPA) is powerful, it requires learning Rego. Kyverno offers an alternative: managing policies using the same YAML patterns you already use for Kubernetes.

Why Kyverno?

1. YAML-Native: No new language to learn. If you can write a Kubernetes manifest, you can write a Kyverno policy.
2. Mutate, Validate, Generate: Kyverno can not only block non-compliant resources (validate) but also fix them (mutate) or create new ones (generate), like default NetworkPolicies for new namespaces.
3. Audit Mode: Test policies without blocking deployments to see what would have been rejected.

Common Use Cases

• Enforce Best Practices: Disallow privileged containers, mandate resource limits, or require specific labels.
• Auto-Injection: Automatically inject sidecars or environment variables into pods based on annotations.
• Resource Generation: Automatically create a ConfigMap or a Secret whenever a new namespace is created.

How to roll it out safely

• start in audit mode to understand impact
• ship a small set of baseline policies (pod security, required labels, resource limits)
• add an exception path for justified constraints (time-bounded, documented)

When Kyverno shines

Kyverno is a great fit when platform teams want policy-as-code that is approachable for Kubernetes engineers and easy to embed into golden paths.

Practical examples worth starting with

If you want early wins, pick policies that prevent common incidents:

• require resources.requests and resources.limits
• enforce non-root containers and safe capabilities
• block images from untrusted registries
• generate a default-deny NetworkPolicy per namespace

Kyverno’s mutate/generate features are especially useful to make the secure option the default.

Common pitfalls

• Too many policies too early: roll out gradually to avoid friction and bypasses.
• Unclear error messages: make denial reasons actionable (what to change).
• No testing: policies are code; version them and test them in CI.

What to measure

• audit-mode violation rate over time
• number of enforced denials (and top reasons)
• number of active exceptions and their expiry dates

Conclusion

Kyverno simplifies the adoption of Policy-as-Code by making it accessible to anyone familiar with Kubernetes. It provides a powerful, native way to ensure that your clusters remain secure, compliant, and standardized without adding excessive complexity to your workflow.