Yeah. That won’t work. It has never worked. I don’t know how someone suggested that it would. I don’t know how I didn’t notice that someone suggested that it would. And the point of the two-container setup, is that you mostly never upgrade data.
If you need to upgrade data, then you need to shutdown web only and then rebuild data, then web_only. I updated the OP.
If you get port conflict errors then it’s likely because when docker restarted it first restarted the old app container and it’s what is grabbing the port. You can check with
docker ps
and see if app is running. You hope that it is, as that will explain the port issue.
You probably need to
docker stop app; docker rm app