Fly.io reference

Quick references for often-used resources like flyctl and fly.toml. Or dig a little deeper into Fly.io capabilities and how they work.

About Fly.io

• Architecture: A brief overview of how Firecracker VMs, Anycast networking, Fly Proxy, and the backhaul network come together to create Fly.io’s infrastructure.

• Regions: The regions around the world where we run servers so your apps can run close to your users.

• Machine migration: How Fly.io automatically migrates your app’s Machines from problematic hosts to healthy hosts.

Reference docs

• flyctl: The flyctl CLI reference documentation.

• App Configuration (fly.toml): The settings for configuring your app in the fly.toml configuration file. The app configuration includes how the app is built, its volume mounts, network services, and more.

• Fly Launch: A deeper dive into how Fly Launch creates and configures new apps.

• Fly Proxy: Learn about how Fly Proxy routes requests, handles connections, and does load balancing.

• Fly Proxy autostop/autostart: Learn how Fly Proxy determines excess capacity for an app to shut down or suspend Machines when they’re not needed and start them back up when there’s traffic.

• Health Checks: Learn how Fly monitors your apps health through HTTP, TCP, and custom checks to verify availability and trigger automatic restarts when needed.

Working with Fly.io

• Autoscaling: Adjust the number of running or created Fly Machines dynamically.

• Builders: The different ways you can assemble applications into deployable images for Fly.io.

• Load Balancing: How Fly Proxy distributes traffic to your application instances based on load, closeness, and concurrency settings.

• Migrating from AWS to Fly.io overview: A guide with considerations for moving from AWS to Fly.io.

• Multiple processes inside a Fly.io app: The different ways to run multiple processes inside a Fly App.