opa

Rules such as who may access a service or which deployment settings are acceptable often get duplicated across systems. Open Policy Agent, or OPA, evaluates those rules separately from application code: a caller supplies structured information, and OPA returns a decision. Teams can then manage and review policy in one place. The calling system must enforce the result. For Kubernetes admission checks, Gatekeeper provides a specific integration around OPA rather than being interchangeable with a plain OPA deployment.

Current guidance

Its official Kubernetes guide recommends Gatekeeper for admission control and explains the added constraint templates, constraints and audit capabilities. A historical plain-OPA chart should not be described as interchangeable with Gatekeeper’s custom resources.

Inventory how policies are delivered and which component enforces their results. The OPA v1 upgrade guide distinguishes bundle producers from consumers and recommends upgrading producers first so bundle metadata can describe the Rego version. Compatibility flags can support a staged transition, but they do not prove that a policy’s decisions remain correct.

Test positive and negative admission cases, missing input and evaluation errors before enforcing a change. Decide timeout and failure behavior deliberately and preserve a way to repair an accidentally restrictive policy. Audit findings and admission denials answer different questions: an existing object can require remediation even if new objects are blocked. This review provides documented integration and language-migration boundaries without claiming that a policy set was executed or that deployment automatically enforces a security standard.