Symptom: restart (or stop) of salt-minion on my systemd-based centos 7 box caused all my daemon processes that were started by the salt-minion to also be killed

Cause: looks like this is related to how systemd kills off all processes in the "control-group" of a service "unit" - in this case the salt-minion service

Suggested fix: change the [Service] section for /usr/lib/systemd/system/salt-minion.service to add:
KillMode=process

which, i believe, means when shutting down salt-minion, only send the kill signal to the salt-minion process itself - leave other spawned daemon processes alone

this fixed the issue for us