Architecture: Docker

You ship a service that works perfectly on your laptop. It hits staging and dies immediately. The stack trace points at a shared library your machine had and the staging box did not. Someone on the team says the words every engineer has heard: "works on my machine." The old fix was a virtual machine. Package the whole operating system, ship the image, run it anywhere. It works, but you are shipping gigabytes of kernel and userland to so… Read More

Explained: Canary Releases, Blue/Green Deployments, and A/B Testing

Your team has just merged a significant change to the checkout flow. The pull request looked clean, the tests passed, staging was fine. But the last time you pushed a change like this straight to production, conversion dropped 12% for three hours before anyone noticed. You want to ship it — but not to everyone at once. You want a way to expose it to a small slice of real traffic, watch the numbers, and either expand it or pull it back. That insti… Read More