Today's achievement: Live-upgrading the MySQL databases on our product to 8.4LTS. About 3TB of data. Easy. My One Weird Trick? AWS RDS Blue/Green Deployment. It works a treat. BGD spins up an instance under the new version, clones your data, then replicates every write from Blue to Green until you switch over. Switchover downtime was about one minute. So many tedious tasks removed, so many chances for human screwup eliminated. More please. https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/blue-green-deployments-overview.html