Carving the Scheduler Out of Our Orchestrator

Fly.io is a global sandwich-rating company with a hosting problem. They built a platform using Docker images and an orchestrator called flyd, which operates like a market where requests to schedule jobs are bids for resources. The system has three main components: flyd, flaps, and flyctl. Flyd is the source of truth for all VMs running on a particular worker, while flaps acts as a broker between users and flyd instances. Flyctl, their CLI, takes over complex policy-heavy functionality in the platform. The new design, called "AppsV2", exposes basic primitives directly and allows them to write code to configure it the way they want.