Since 2014, I’ve been working on various projects which containerized Drupal in a production environment. There have always been a few growing pains—there will for some time, as there are so few places actually using Docker or containers in a production environment (at least in a ‘cloud native’ way, without tons of volume mounts), though this is changing. It was slow at first, but it’s becoming much more rapid.
You might think that Drupal and Docker work together nicely. They definitely can and do, in many cases, as we see with local development environments built around Docker, like Docksal, Ddev, Lando, and even Drupal VM. But local development environments, where the Drupal codebase is basically mounted as a volume into a Docker container that runs the code, differ radically from production, where the goal is to ‘contain’ as much of production into a stateless container image as possible, so you can scale up, deploy, and debug most efficiently.