OPA vs Kyverno

Policy.

Overview

OPA and Kyverno are two leading Kubernetes policy engines with different language and integration models. OPA (Open Policy Agent) is general-purpose with Rego (works for K8s, Terraform, microservice authz); Kyverno is K8s-native (YAML-based policies, no separate language to learn). The right answer depends on whether the policy engine needs to span multiple systems or just Kubernetes.

• OPA: general-purpose plus Rego. One engine for K8s admission, Terraform validation, microservice authz. Default when policy needs to span multiple systems.
• Kyverno: K8s-native plus YAML. Policies as Kubernetes resources, no separate language, validating and mutating webhooks. Default for Kubernetes-only policy.
• Operational fit per team. Existing Rego expertise biases toward OPA; teams that want to avoid learning a new language bias toward Kyverno.
• Per-cluster choice. Different clusters may pick differently. Document the rationale per cluster.

The approach

Workload-driven choice, per-team operational fit considered, documented rationale per cluster. The discipline is making the policy engine choice once with a written reason rather than running both engines (which doubles policy debugging surface).

• Workload-driven. Engine per cluster. Reality drives the answer.
• OPA for cross-system policy. Same engine for K8s, Terraform, microservices. Default for orgs with policy needs beyond K8s.
• Kyverno for K8s-only policy. YAML-native policies, no Rego. Default when Kubernetes is the only policy surface.
• Operational fit plus documented rationale. Team workflow considered; per-cluster rationale captured. Future migrations have a paper trail.

Why this compounds

The right policy engine compounds across years. Policy patterns and team expertise align with the engine; cross-cluster tooling (policy testing, exception handling, audit) gets built once and reused. By year two the engine choice is automatic per cluster.

• Better operational fit. Engine matches team. Velocity stays high.
• Better security posture. Right engine means policies actually get written and enforced. Real protection follows.
• Workload-driven decisions. Replaces tribal preference with documented rationale. Quality of choice improves.
• Year-one investment, year-two habit. First policy is the investment; subsequent ones inherit the patterns.