Does anyone have experience with this?
A deployment that can autoscale is harder to accomplish, but still not impossible. AFAICT, most people doing this are building releases with Distillery, wrapping those releases in a Docker image, then using the deployment and orchestration tools of their choice. Monica Hirst gave a talk about doing this with AWS CodeDeploy last year at Empire City Elixir as well[4].
[1] https://github.com/bitwalker/distillery
[2] https://github.com/boldpoker/edeliver
The main benefit of Go, I think, is that it can cross-compile builds. Erlang and Elixir don't have any way to do that, so if you develop on Mac and deploy on Linux you'll need to build your release in a VM or on a build server running Linux.
And it looks like you can cross compile BEAM anyway. http://erlang.org/faq/implementations.html. It's just a C program isn't it so why wouldn't you be able to?
The goal of a release is to bundle together everything you need -- your program, the VM that runs it, your config files, and any instructions necessary to upgrade/downgrade from another version of your code.
The beams themselves are cross-platform bytecode, but in practice beam files are not distributed on their own (except for patching). Typically you'll ship them as part of the released package which includes ERTS, your application, and all required dependencies (system libraries, other apps/libraries, and any native dependencies you've introduced). It excludes anything you don't declare as necessary from the final release package
In practice, people will usually use either the official release tooling or third party tooling to create platform-specific releases.
[1] http://erlang.org/doc/installation_guide/INSTALL-CROSS.html [2] http://www2.erlangcentral.org/wiki/?title=Cross_compiling
It is getting better but right now the few things I can recommend the most are:
• learn what an "OTP release" actually is and what it means. This alone will save you days of your life.
• do rolling restarts, doing live upgrades is difficult and not necessary for the vast majority of applications.
• read the prod.exs config, there's a commented out setting you'll need to enable. I forget the name of it, but it's on my github "tehprofessor" with the repo "flying with Phoenix" (its probably outdated in many ways but that setting is essential).
• remember the application is compiled and then run, so you really won't get any runtime configuration (likes Rails' environments).
• Docker can alleviate build pain a bit, as it stabilizes your environment-- I don't use it myself but it makes building a bit more pleasant from what others have told me.
• you'll very likely need to include all the applications, including ones listed in your dependencies (it's a pain in the ass), in your mix.exs applications list if you're using exrm.
... it's been a couple months as I've been on a coding hiatus for health reasons (and a broken arm) but I believe most of the above should still be very true.
That said and even with all the bitching I've had about it, I still love Elixir and Erlang. Though I've been moving more to pure Erlang as time goes on (FWIW).
Edit: clarity and note about loving me some elixir/erlang.
I think the second part is still possible, since if it can be done for Erlang it can be done for Elixir.
-- Original post --
I haven't found production deployments to be particularly painful, I'd be interested to hear what kind of troubles you've run into.
Runtime configuration is definitely possible - you can deploy configuration files with your application and determine which one you want to load. It's not built-in, but it's a few lines of code to do it manually. You can also always use environment variables, which is arguably a better approach.
0: https://github.com/HashNuke/heroku-buildpack-elixir 1: https://gist.github.com/joakimk/48ed80f1a7adb5f5ea27
It should be pretty far down in the list of things that influence your choice, imo, since it's basically a solved problem.
I can honestly say I've not been this excited about a language in quite a while. Working with Go is pretty straightforward... but it's a complete bore. The more I dig into Elixir the more I desire to use it full-time.
If you need any specific help, feel free to contact me!
Disclaimer: I'm the author of exrm and distillery, so I'm probably biased.
I found that besides hot-code updates, there is not as much magic as one could think, and once you "grasp" the idea of a build machine, it should be pretty straigt-forward. Throw in an HAProxy for rolling deploys and you have a sweet zero-downtime solution!
Feel free to contact me if you need someone to help out (from some free general tips and tricks to supporting your team as a consultant).
Flynn is amazingly easy to deploy. It provisions DO/AWS/Azure then bootstraps a single node or cluster literally at the push of a button. Then you just add it to your repo and push (provided the buildpack is already set up)