Nginx supports online upgrades, however there do not appear to be any scripts extant to automate the process.

To remedy the situation, nginx-graceful supports transactional upgrades/restarts of nginx -- i.e. transactions can be tested and then aborted back to the quiesced old master process.

As bash hacks go, on error it will exit and dump a stacktrace of bash calls, so it has a couple of niceties not normally found in the bash world.