In this episode of Turn Stories, I sit down with Anthony Sottile, who led Lyft's migration from Python 2 to 3.  They did 150 services in less than six months. But what stood out wasn't just the scale or the timeline, it was the approach.   They really leaned on tooling so they could ratchet progress forward, and then they'd lock it in with CI rules so nothing backslid.   They would ship automated PRs, and if nobody complained but nobody looked at them, they would just purge them, and they trusted their infrastructure.   They would do deployments where even if there were errors, they knew the system would retry, and there wouldn't be any user visible impact.   And that made for a really powerful migration story. So we talk about what worked, we talk about what didn't, and some of the most hilarious failures across a couple of key services.  -----   Get Tern Stories in your inbox: https://tern.sh/youtube   Go subscribe to Anthony! ➡️ https://www.youtube.com/anthonywritescode