TL; DR: how should I write a Dockerfile or docker commands to run docker containers so that I can stop and exit the running docker container when I hit ctrl+c?

Background

I need to run an infinite while loop in shell script. When I ran this script locally, the ctrl+c command will exit the infinite loop.

# content of sync.sh

while true; do
  echo "Do something!"
  some_syncing_command || {
    rm -rf /tmp/healthy && break
  }
  echo "Finish doing something!"
  touch /tmp/healthy
  sleep ${waitingSeconds}
done

So based on the shell script, I then created a Docker Image with the following Dockerfile content:

FROM debian:stretch 
COPY sync.sh .

ENTRYPOINT ["/sync.sh"]

and build the image by running docker build -t infinite-loop .

Problem

However, after trying different attempts to run the infinite-loop image, I cannot stop and exit the running docker container after hitting ctrl + c. Here are the docker commands I used to run the docker image:

1. docker run --rm to-infinity-1 infinite-loop
2. docker run --rm -it to-infinity-2 infinite-loop
3. docker run --rm -d to-infinity-3 infinite-loop, then run docker attach on to-infinity-3

All of the above commands fail to stop and exit the infinite loop after executing ctrl+c directly. Hence I need to run docker stop [container-name] to stop the running containers of infinite loops. What should I change in my implementation to resolve this problem?

Thank you.

Edit: additional context, I am using kubernetes with the infinite loop container. I wonder if this ctrl+c problem (related to SIGINT) will interfere with kubernetes if I want to gracefully stop and exit the running pod. Note that although the ctrl+c is problematic, I was still able to use docker stop to stop the running containers.