Shopify is one of the largest commerce web sites in the world, with over 500,000 merchants including Kylie Jenner and Kanye West. In 2017, we made the decision to move from primarily co-located data centres to the cloud.This talk will dig into why we made the decision to abandon the DC, one that may interest other companies considering the same move. We'll carefully talk through each step of the process—how we planned, managed and executed the migration.We'll also dive deep into the tooling we built to make this possible: a tool for performing zero-downtime shard failovers; a live shop mover to migrate shops between shards; among others. These tools are what allowed us to successfully perform the migration with almost no downtime for our merchants.We'll also go into our performance tuning methodologies and capacity planning process. And of course, no project executes as planned, so we'll also share some of the problems we encountered and lessons learned along the way.