01 · The problem
A deploy took an afternoon, a checklist, and one specific person who knew which steps the checklist left out.
02 · The spec
We specced the process before automating it — including the steps that only existed in somebody's head. Writing them down was, on its own, worth the sprint.
03 · The build
Three milestones: inventory and configuration, the pipeline itself, then observability and rollback. Everything test-first, because a deploy tool that fails quietly is worse than no tool.
04 · The outcome
Deploys run in minutes, unattended, across more than three hundred servers — and the runbook means anybody on the team can operate it.