A Comparative Analysis of Network Policy Implementation in Kubernetes: Leveraging Flannel and Calico for Enhanced Security and Performance

Abstract

As Kubernetes solidifies its position as the de facto standard for container orchestration, the imperative for robust network security and granular traffic control within clusters has become paramount. This paper presents a comparative analysis of Kubernetes Network Policy implementation, evaluating the efficacy of two prominent Container Network Interface (CNI) plugins: Flannel and Calico. Moving beyond basic configuration, our methodology involves deploying a standardized test environment to quantitatively assess how these tools enforce complex policy definitions, including advanced ingress/egress rules and namespace isolation. The results demonstrate that while Flannel offers simplicity and lower resource overhead suitable for less complex deployments, Calico provides superior performance and advanced policy capabilities for security-critical, high-demand environments. Furthermore, the study explores the extension of network policies into multi-cluster and hybrid cloud scenarios. The findings offer a structured framework and practical insights for administrators to select and optimize network policy enforcement tools, thereby enhancing the security posture and operational efficiency of their Kubernetes deployments.