A container keeps dying and docker ps -a shows Exited… (Docker interview question)

The process was killed with SIGKILL, often by the out-of-memory killer or after docker stop timed out

Exit codes above 128 mean a signal killed the process. 137 is 128 + 9, and signal 9 is SIGKILL. This happens with the out-of-memory (OOM) killer, or when docker stop times out. To tell them apart, check docker inspect for OOMKilled: true.

It is not "The app threw an uncaught exception": an uncaught Node exception usually exits with 1. It is not "a clean shutdown" after SIGTERM either: that would give 143 (128 + 15).

docker CLI reference (https://docs.docker.com/reference/cli/docker/)docs.docker.com
docker container run (https://docs.docker.com/reference/cli/docker/container/run/)docs.docker.com