Bridging Clusters: A Comparative Look at Multi-Cluster Networking Performance in Kubernetes

Microservices and containers have transformed the way applications are developed, tested, deployed, scaled, and managed. Several container orchestration platforms, like Kubernetes, have emerged, streamlining container management at scale and providing enter­prise-grade support for application modernization. Driven by application, compliance, and end-user requirements, companies opt to deploy multiple Kubernetes clusters across public and private clouds. However, deploying applications in multi-cluster environments presents distinct challenges, especially managing the communication between the microservices spread across clusters. Traditionally, custom configurations, like VPNs or firewall rules, were required to connect such complex setups of clusters spanning the public cloud and on-premise infrastructure. This industry paper presents a comprehensive analysis of network performance characteristics for three popular open-source multi-cluster networking solutions (namely, Skupper, Submariner, and Istio), addressing the challenges of microservices connectivity across clusters. We evaluate key factors such as latency, throughput, and resource utilization using established tools and benchmarks, offering valuable insights for organizations aiming to optimize the network performance of their multi-cluster deployments. Our experiments revealed that each solution involves unique trade-offs in performance and resource efficiency: Submariner offers low latency and consistency, Istio excels in throughput with moderate resource consumption, and Skupper stands out for its ease of configuration while maintaining balanced performance.