Gatekeeper on Support Tools

OPA Gatekeeper: Production-Grade Policy Enforcement for Kubernetes Clusters

Thu, 15 Oct 2026 00:00:00 -0500

Open Policy Agent (OPA) Gatekeeper has become the industry standard for policy-based control in Kubernetes environments. As a CNCF graduated project, Gatekeeper extends OPA’s policy-as-code capabilities with Kubernetes-native resources, providing declarative admission control that enforces organizational policies across clusters.

In this comprehensive guide, we’ll explore enterprise-grade Gatekeeper implementations, covering constraint template development, mutation policies, audit frameworks, and integration patterns that have proven effective in managing thousands of workloads across multi-tenant environments.

How to use OPA Gatekeeper to only allow images from a private registry.

Fri, 11 Jun 2021 01:11:00 +0000

By default, Kubernetes will pull from Docker Hub unless the deployment requests a fully qualified path. For example, if you deploy a pod with the image rancherlabs/swiss-army-knife, Kubernetes will default index.docker.io/rancherlabs/swiss-army-knife. This is works for environments that can pull images from the internet. But in environments that don’t have internet access or if your security team requires all images to be scanned before being deployed. To solve this issue, you’ll need to instruct your application teams to update to use a private registry IE private.example.com/rancherlabs/swiss-army-knife., But there is always a chance that an application team forgets to change their image path in their code. Now you have pods stuck in imagepullbackoff. To prevent this kind of issue, we will set up OPA Gatekeeper to block all deployment requests that are missing our private registry IE private.example.com.

How to use OPA Gatekeeper to require a label on all namespaces.

Fri, 11 Jun 2021 01:11:00 +0000

By default, Kubernetes will create namespaces without any labels. This can tracking the owner of the namespace difcult. Also, by having all namespaces labeled. You can use labels for running show-back and charge-back reports based on owner labels.