The container exits immediately. What should I check?

Definition:

A container stays running while its main process remains alive. An immediate exit usually means the command finished, failed startup or was killed, rather than that Docker randomly stopped a healthy application. Logs, exit status and runtime configuration tell you which case occurred.

Key points:

• Read logs and the exit code; check the startup command and missing configuration.

• Confirm required files, dependencies and permissions exist in the image.

• The main process must keep running; starting it in the background can make the container exit.

• Inspect memory limits and termination reasons if the process was killed without a normal application exception.

Interview point:

• Fix the foreground process or startup failure rather than adding an endless sleep to keep a broken container alive.