# Admission Controllers * Admission controllers checks whether request to apiserver should be allowed or not (after authentication and authorization) * Dynamic admission controllers * can call validating service with webhook * this is beneficial for example in managed Kubernetes environments where API server can't be modified * configured with `ValidatingWebhookConfiguration` * Mutating admission controller can modify workloads, for example inject init containers * Kubernetes can send out `AdmissionReview` object to admission controller, which wraps the object which will be validated * Admission controller need then respond with the validation results to the apiserver ## Resources * TGI Kubernetes 119: Gatekeeper and OPA -