Apache has a
graceful option which can scan for modification in
http.conf without restarting Apache. What about nginx?
nginx supports the following signals :
TERM, INT - Quick shutdown QUIT - Graceful shutdown HUP - Configuration reload: Start the new worker processes with a new configuration, Gracefully shutdown the old worker processes USR1 - Reopen the log files USR2 - Upgrade Executable on the fly WINCH - Gracefully shutdown the worker processes
HUP is what you are looking for, so
sudo kill -HUP pid (nginx pid)
I wrote about how to restart nginx with zero downtime a while ago. This may be helpful for you.