Fly.io rebuilds 6PN phonebook with lazy routing

Fly.io rebuilt its 6PN private networking system by replacing a resource-heavy fleet-wide routing table, known as the phonebook, with a lazy, on-demand lookup model. The new design uses VXLAN events and local SQLite queries to fetch routes only when a Machine attempts to communicate with an unknown address. This reduces the per-host routing table to a few hundred entries and significantly improves observability and reliability. Open article →