Kubernetes at GitHub

Over the last year, GitHub has gradually evolved the infrastructure that runs the Ruby on Rails application responsible for github.com and api.github.com. We reached a big milestone recently: all web and API requests are served by containers running in Kubernetes clusters deployed on our metal cloud. Moving a critical application to Kubernetes was a fun challenge, and we’re excited to share some of what we’ve learned with you today.

Why change?

Before this move, our main Ruby on Rails application (we call it github/github) was configured a lot like it was eight years ago: Unicorn processes managed by a Ruby process manager called God running on Puppet-managed servers. Similarly, our chatops deployment worked a lot like it did when it was first introduced: Capistrano established SSH connections to each frontend server, then updated the code in place and restarted application processes. When peak request load exceeded available frontend CPU capacity, GitHub Site Reliability Engineers would provision additional capacity and add it to the pool of active frontend servers.

Read more at GitHub