School of Information and Communication Engineering, Chungbuk National University, Cheongju 28644, Korea.
Sensors (Basel). 2022 Apr 8;22(8):2869. doi: 10.3390/s22082869.
Kubernetes (K8s) is expected to be a key container orchestration tool for edge computing infrastructures owing to its various features for supporting container deployment and dynamic resource management. For example, its horizontal pod autoscaling feature provides service availability and scalability by increasing the number of replicas. kube-proxy provides traffic load-balancing between replicas by distributing client requests equally to all pods (replicas) of an application in a K8s cluster. However, this approach can result in long delays when requests are forwarded to remote workers, especially in edge computing environments where worker nodes are geographically dispersed. Moreover, if the receiving worker is overloaded, the request-processing delay can increase significantly. To overcome these limitations, this paper proposes an enhanced load balancer called resource adaptive proxy (RAP). RAP periodically monitors the resource status of each pod and the network status among worker nodes to aid in load-balancing decisions. Furthermore, it preferentially handles requests locally to the maximum extent possible. If the local worker node is overloaded, RAP forwards its requests to the best node in the cluster while considering resource availability. Our experimental results demonstrated that RAP could significantly improve throughput and reduce request latency compared with the default load-balancing mechanism of K8s.
Kubernetes（K8s）有望成为边缘计算基础设施的关键容器编排工具，因为它具有支持容器部署和动态资源管理的各种功能。例如，其水平 pod 自动缩放功能通过增加副本数量提供服务可用性和可伸缩性。kube-proxy 通过将客户端请求平均分配给 K8s 集群中应用程序的所有 pod（副本）来提供流量负载均衡。但是，当请求转发到远程工作节点时，这种方法可能会导致长时间的延迟，尤其是在边缘计算环境中，工作节点是地理上分散的。此外，如果接收工作节点过载，请求处理延迟会显著增加。为了克服这些限制，本文提出了一种称为资源自适应代理（RAP）的增强型负载均衡器。RAP 定期监视每个 pod 的资源状态和工作节点之间的网络状态，以帮助进行负载均衡决策。此外，它尽可能优先在本地处理请求。如果本地工作节点过载，RAP 将其请求转发到集群中最佳的节点，同时考虑资源可用性。我们的实验结果表明，与 K8s 的默认负载均衡机制相比，RAP 可以显著提高吞吐量并减少请求延迟。
