What Is OPA Gatekeeper?
OPA Gatekeeper is a policy controller for Kubernetes that integrates Open Policy Agent with the admission webhook flow. Administrators define constraints and constraint templates, and Gatekeeper evaluates incoming resources against them at admission time. Resources that break a constraint are denied, and Gatekeeper can also audit existing objects for violations.
Why it matters
Clusters need guardrails such as requiring resource limits or banning privileged pods. Gatekeeper enforces these as code at the API boundary, so non-compliant manifests never get admitted.
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