From the Executive Summary: "Kubernetes® is an open-source system that automates the deployment, scaling, and management of applications run in containers, and is often hosted in a cloud environment. Using this type of virtualized infrastructure can provide several flexibility and security benefits compared to traditional, monolithic software platforms. However, securely managing everything from microservices to the underlying infrastructure introduces other complexities. The hardening guidance detailed in this report is designed to help organizations handle associated risks and enjoy the benefits of using this technology. [...] This guidance describes the security challenges associated with setting up and securing a Kubernetes cluster. It includes hardening strategies to avoid common misconfigurations and guide system administrators and developers of National Security Systems on how to deploy Kubernetes with example configurations for the recommended hardening measures and mitigations."
Department of Defense: https://media.defense.gov/