Static Validation Patterns#

Static validation catches infrastructure errors before anything is deployed. No cluster needed, no cloud credentials needed, no cost incurred. These tools analyze configuration files – Helm charts, Kubernetes manifests, Terraform modules, Kustomize overlays – and report problems that would cause failures at deploy time.

Static validation does not replace integration testing. It cannot verify that a service starts successfully, that a pod can pull its image, or that a database accepts connections. What it catches are structural errors: malformed YAML, invalid API versions, missing required fields, policy violations, deprecated resources, and misconfigured values. In practice, this covers roughly 40% of infrastructure issues – the ones that are cheapest to find and cheapest to fix.

OPA Gatekeeper: Policy as Code for Kubernetes#

Gatekeeper is a Kubernetes-native policy engine built on Open Policy Agent (OPA). It runs as a validating admission webhook and evaluates policies written in Rego against every matching API request. Instead of deploying raw Rego files to an OPA server, Gatekeeper uses Custom Resource Definitions: you define policies as ConstraintTemplates and instantiate them as Constraints. This makes policy management declarative, auditable, and version-controlled.