Gatekeeper is a policy controller for Kubernetes that enforces custom policies on cluster resources through admission control.
Gatekeeper solves the problem of enforcing organizational policies and security standards across Kubernetes clusters without requiring changes to application code. It works by integrating with Kubernetes admission webhooks to intercept and evaluate resource requests against policies written in Rego, the policy language from Open Policy Agent. Policies can validate resource configurations, enforce naming conventions, require specific labels or annotations, and prevent non-compliant resources from being created or modified. The tool also supports mutation, allowing it to automatically modify resources to meet policy requirements rather than simply rejecting them.
Teams should choose Gatekeeper when they need fine-grained control over what gets deployed to their clusters and want to express policies in a declarative, auditable way. It suits organizations that have complex compliance requirements, multiple teams sharing clusters, or security standards that must be consistently applied. The tool is particularly valuable for preventing misconfigurations at admission time rather than discovering problems after deployment. Gatekeeper is built on Open Policy Agent, which means policies benefit from OPA's mature policy language and ecosystem, though this also means operators need to learn Rego syntax.
The project shows sustained development activity with regular commits addressing bug fixes and feature enhancements. Pull requests receive timely review and feedback from maintainers. The issue tracker reflects active engagement with users reporting problems and requesting features, with maintainers providing detailed responses and guidance. The codebase demonstrates ongoing refinement of core functionality and expansion of capabilities around policy evaluation and mutation features.
