Useful to move Discourse from one server to another: recover Discourse from a backup using the command line
Roughly based on Move your Discourse instance to a different server post. But without using the web UI. Because sysadmins prefers terminal.
How to know the reason why a docker container exits?
Others have mentioned docker logs $container_id to view the output of the application. This would always be my first thing to check.
Next, you can run a docker inspect $container_id to view details on the state.