Simon Willison’s Weblog

MRSK. A new open source web application deployment tool from 37signals, developed to help migrate their Hey webmail app out of the cloud and onto their own managed hardware. The key feature is one that I care about deeply: it enables zero-downtime deploys by running all traffic through a Traefik reverse proxy in a way that allows requests to be paused while a new deployment is going out—so end users get a few seconds delay on their HTTP requests before being served by the replaced application. # 29th April 2023, 11:54 pm

How to do Zero Downtime Deployments of Docker Containers. I’m determined to get reliable zero-downtime deploys working for a new project, because I know from experience that even a few seconds of downtime during a deploy changes the project mentality from “deploy any time you want” to “don’t deploy too often”. I’m using Docker containers behind Traefik, which means new containers should have traffic automatically balanced to them by Traefik based on their labels. After much fiddling around the pattern described by this article worked best for me: it lets me start a new container, then stop the old one and have Traefik’s “retry” mechanism send any requests to the stopped container over to the new one instead. # 16th January 2020, 11:12 pm