Unless you've written very poorly behaving software, you kill it by sending it a SIGTERM, and waiting for it to exit. This is true of software both within and outside of containers.

The fact `docker kill` defaults to using SIGKILL instead of SIGTERM is unfortunate, and something one should be aware of before deploying a process with docker, but again, this does not make the process running within the container inherently less reliable.

edit: Looks like `docker stop` does the right-ish thing -- sends a SIGTERM, then only resorts to SIGKILL after a timeout has expired.