Kubernetes Webhook
A Kubernetes Webhook is an HTTP callback mechanism that allows external services to intercept and modify requests to the Kubernetes API server, enabling custom validation, mutation, or admission control logic. It acts as an extension point for integrating external systems, such as security scanners, policy engines, or custom automation, into the Kubernetes control plane. Webhooks are commonly used in admission controllers to enforce policies, validate resources, or mutate objects before they are persisted.
Developers should learn and use Kubernetes Webhooks when they need to enforce custom policies, validate resource configurations, or automate operations in a Kubernetes cluster, such as ensuring security compliance, injecting sidecar containers, or managing resource quotas. They are essential for building platform engineering solutions, implementing GitOps workflows, or integrating third-party tools like OPA Gatekeeper or Kyverno for policy management. Webhooks provide a flexible way to extend Kubernetes without modifying the core API server.