An e-commerce platform hosted on Google Kubernetes Engine (GKE) experiences an unprecedented traffic spike during a flash sale. The primary regional cluster reaches its maximum physical node quota and compute limits, causing critical user checkout requests to degrade alongside non-critical recommendation and browsing requests. You need to implement a traffic shedding and load balancing strategy using Google Cloud native networking to shed non-essential traffic, prioritize critical transaction journeys, and automatically overflow excess global traffic to healthy secondary clusters once service capacity limits are exceeded. What should you do?

Deploy a multi-cluster Gateway using the gke-l7-global-external-managed-mc GatewayClass, define HTTPRoute rules with traffic splitting and Service Extensions to shed or deprioritize non-essential traffic, and configure service capacity thresholds on backend services to overflow excess load to secondary clusters.: What the multi-cluster Gateway solution is The multi-cluster Gateway API (gke-l7-global-external-managed-mc) combined with HTTPRoute and GKE Gateway Service Extensions provides an advanced Layer 7 global traffic management and load balancing framework across multiple GKE clusters and Google Cloud regions. How it meets the requirements Service capacity and automated load shedding/overflow: Defining service capacity specifications within GKE Gateway resources allows the load balancer to determine the exact traffic threshold a regional service can process before Pods autoscale or excess traffic automatically overflows to secondary regional clusters (e.g., from gke-asia to gke-eu). Traffic splitting and prioritization: HTTPRoute rules enable fine-grained, path-based, and header-based routing alongside weight-based traffic splitting to route critical checkout traffic to dedicated, protected backend services while throttling or degrading non-critical paths (such as product recommendations). Graceful degradation and custom control: GKE Gateway Service Extensions allow injecting custom logic at the edge to inspect request headers, modify payloads, or shed/reject non-essential requests when physical limits are approached. Key advantages and capabilities Global Anycast IP routing: Leverages Google's global network to terminate connections close to users while orchestrating cross-cluster failover and capacity management. Multi-cluster resilience: Automatically shifts traffic away from saturated clusters to available capacity in other geographic regions without manual DNS manipulation. Declarative Kubernetes native control: Configured entirely via Kubernetes Gateway API standard resources (Gateway, HTTPRoute, GCPBackendPolicy). Advanced Layer 7 traffic steering: Supports weight-based splitting, header rewrites, and integration with custom metrics via the Open Request Cost Aggregation (ORCA) standard. Why this is optimal This approach natively solves multi-cluster capacity overflow and granular Layer 7 load shedding directly at the Cloud Load Balancing layer without introducing custom proxies or unmanaged routing infrastructure.