Globally Distributed Postgres

This is a story about a cool hack we came up with at Fly. The hack lets you do something pretty ambitious with full-stack applications. What makes it cool is that it’s easy to get your head around, and involves just a couple moving parts, assemble...

By Alexander Koutmos

8 min Read

Monitoring Elixir Apps on Fly.io With Prometheus and PromEx

Fly.io takes Docker containers and converts them into fleets of Firecracker micro-vms running in racks around the world. If you have a working Docker container, you can run it close to your users, whether they're in Singapore or Amsterdam, with ju...

By Kurt Mackey

6 min Read

Fly Is Hiring SREs

Anyways, we’re hiring for our SRE team. You can read that introduction and get a good idea of how intense our SRE challenge is. To further set the scene, two important true things about ops at Fly.io: ops is a very big deal here, and, because we’r...

By Mark Ericksen

5 min Read

Observing Elixir in Production

Elixir, Erlang, and really just the BEAM has a feature called "Observer". It's fun showing it to people new to Elixir because it's just so cool! It's a WxWidgets graphical interface that connects in realtime to a running Erlang node and lets you "...

By Mark Ericksen

6 min Read

Livebook is a secret weapon for documentation

Every application has that core, most important thing that it does. It is the reason the application exists. It's that central idea that everything else is there to support. A major hurdle for new developers joining a project can be understanding ...

By Thomas Ptacek

10 min Read

Hooking Up Fly Metrics

We’ve written a bit, for a general audience, about how Fly collects and manages metrics. If you’re just sort of generally interested in metrics and observability, go read that first. Meanwhile, if you’re a Fly user, or considering becoming such a...

By Thomas Ptacek

12 min Read

Fly's Prometheus Metrics

We should talk a bit about metrics and measurement and stuff, because they’re how we all know what’s going on. There’s two reasons we’ve written this post. The first is just that we think this stuff is interesting, and that the world can always us...

By Mark Ericksen

7 min Read

Building a Distributed Turn-Based Game System in Elixir

One of the best things about building web applications in Elixir is LiveView, the Phoenix Framework feature that makes it easy to create live and responsive web pages without all the layers people normally build. Many great Phoenix LiveView exampl...

By Thomas Ptacek

13 min Read

Docker without Docker

Even though most of our users deliver software to us as Docker containers, we don’t use Docker to run them. Docker is great, but we’re high-density multitenant, and despite strides, Docker’s isolation isn’t strong enough for that. So, instead, we...

By Kurt Mackey

13 min Read

The 5-hour CDN

The term "CDN" ("content delivery network") conjures Google-scale companies managing huge racks of hardware, wrangling hundreds of gigabits per second. But CDNs are just web applications. That's not how we tend to think of them, but that's all the...

By Thomas Ptacek

11 min Read

SSH and User-mode IP WireGuard

But Fly is kind of an odd duck. We run hardware in data centers around the world, connected to the Internet via Anycast and to each other with a WireGuard mesh. We take Docker-type containers from users and transmogrify them into Firecracker micro...

By Kurt Mackey

6 min Read

Elixir is amazing – coincidentally, we're hiring Elixir dev advocates

Fly is a hosting platform for applications. Our users give us containers; we transmute them into fleets of Firecracker micro-VMs and run them on a WireGuard-backed Anycast network that runs application code close to users, anywhere in the world. D...