The API Server is the central component of Kubernetes control plane, typically fronted by a Layer 4 load balancer (e.g., nginx) for high availability. However, as most clients connect to API Server using HTTP/2, a Layer 4 load balancer routes all requests from a single client to the same API Server endpoint, leading to unbalanced load distribution - an issue that becomes more pronounced in large-scale Kubernetes deployments.
KubeGateway is a Layer 7 API Gateway designed specifically for Kubernetes API Server. It provides request-level load balancing, supports proxying to multi kubernetes clusters, enables flexible request routing strategy, and offers advanced traffic management capabilities, including global rate limiting, degradation, and circuit breaking. KubeGateway has been deployed in over 500 production Kubernetes clusters, handling more than 1 million QPS of proxied requests in ByteDance. The largest single Kubernetes cluster it supports has scaled up to 20,000 nodes.