A Foolish Consistency: Consul at Fly.io

Fly.io runs applications by transforming Docker containers into Firecracker micro-VMs connected to a global Anycast network. The company uses Consul, a distributed database for service coordination and discovery, to manage its platform. However, they have faced challenges with Consul's design and performance at scale. Fly.io has developed attache, a local sqlite cache of all Consul's state, which allows their infrastructure services to track updates without directly interfacing with Consul. They are also considering alternative strategies for request routing that are resilient to variability and stale data.