This repository offers a comprehensive library of security policies designed to enhance the security of Kubernetes cluster configurations. The policies are developed in accordance with the CIS Kubernetes benchmark.
We used the CIS 5.1.3 rego in an OPA gatekeeper policy to prevent creation of roles / cluster roles which utilize wildcards.
What did you expect to happen:
The cluster would remain functional.
Anything else you would like to add:
The K8s API periodically checks to ensure the bootstrap roles (admin, cluster-admin, etc.) are present after the control plane comes up. If they are not present, it attempts to reconcile them using a post start hook. If a post start hook cannot complete, the /healthz endpoint starts to return failures. In a managed K8s setting like EKS this causes the load balancer sitting in front of the API to stop routing traffic to it, rendering the cluster dead.
Additional Information:
cluster-admin uses wildcards.
Turns out to be tricky for AWS to correct this, we had to destroy and recreate our cluster to proceed with our Rego and Gatekeeper testing. Hopefully this issue helps folks avoid this in the future.
Details
What steps did you take and what happened:
We used the CIS 5.1.3 rego in an OPA gatekeeper policy to prevent creation of roles / cluster roles which utilize wildcards.
What did you expect to happen:
The cluster would remain functional.
Anything else you would like to add:
The K8s API periodically checks to ensure the bootstrap roles (
admin,cluster-admin, etc.) are present after the control plane comes up. If they are not present, it attempts to reconcile them using a post start hook. If a post start hook cannot complete, the/healthzendpoint starts to return failures. In a managed K8s setting like EKS this causes the load balancer sitting in front of the API to stop routing traffic to it, rendering the cluster dead.Additional Information:
cluster-adminuses wildcards.