Upgrade without any downtime
============================

Before migration to systemd, the nginx initscript provided the ability to
upgrade the running nginx server without any downtime.

This functionality has now been replaced with a downstream shell script,
located at /usr/bin/nginx-upgrade.

Following an update to nginx via the package manager, running nginx-upgrade
will cause a new nginx master to be created, which will then take all new
requests. The old master and workers are then gracefully shutdown without
breaking any existing connections.

See http://wiki.nginx.org/CommandLine for more information.