I'm not sure, but I suspect docker does a docker stop (ie. sending a SIGTERM to a container, and then a SIGKILL after waiting 10 seconds) when performing "rolling updates" on a service. With some images, like [https://hub.docker.com/_/httpd/](those powered by apache2), this is actually a destructive (non-graceful) way to stop containers, since apache needs a SIGWINCH to actually shutdown in a graceful way.

It would be awesome if we could define a signal used to stop services when creating them, for example:

docker service create --stop-signal SIGWINCH --name my-apache-container httpd:latest