VPC Peering Became Your Bottleneck: Cloud-Native Network Architecture Selection and 5 Production-Grade Decisions
Overview At 2 AM, the alert group for a ride-hailing project exploded. The order service P99 latency spiked from 80ms to 600ms, and client-side timeouts were spreading. After a full round of troubleshooting, the culprit turned out to be VPC Peering — the cross-VPC call volume between two core business VPCs had saturated the concurrent connection limit of a single Peering link during peak hours. Meanwhile, 3 out of 12 new Peering connections created via Full Mesh for another recently launched VPC failed due to CIDR overlap, causing routing table chaos that sent some traffic through suboptimal paths....