Shipping a bad release is not the problem. Everyone does it. The problem is what your users see while you notice, and how long the way back takes.

Part 2 of 7 in the Deploy and operate Levelrail series: 1. Install a Self-Hosted PaaS on Your Own Server in Five Minutes ; 2. Roll Back a Failed Docker Deploy Without Downtime (this post); 3. Restart a Docker Container Without Downtime ; 4. Node Graceful Shutdown in Docker: Handle SIGTERM on Deploy ; 5. Update the PHP Docker Image Security Patch, No Downtime ; 6. Docker Container Restarting in a Loop: 5 Causes, Fixed ; 7. Why a Failed Health Check Still Went Live .

In this guide we ship a broken release on purpose to a small demo app, watch the old version keep serving, then roll back with one command. Every command and output below comes from a real run, not a mock-up.

What you need

A running Levelrail instance.…