Debugging a failing Docker container by committing it and overriding the entrypoint with a shell

A developer using Docker Compose found that a Django container kept exiting shortly after launch, showing exit code 127 in the docker ps output. To investigate, they committed the failed container to a new image so its state could be preserved. They then started that image with the entrypoint overridden to launch an interactive shell, using /bin/bash or /bin/sh if bash is unavailable. This gives access to run diagnostic commands inside the container's environment, with the specific checks depending on the problem.