We're using a basic recipe based on our load balancing recipe back in Chapter 8, Load Balancing. With the open source version of NGINX, adding or removing backend servers from an NGINX configuration required a full reload in order to use the new changes. While this only has a minimal impact on lightly loaded systems, this can be a significant problem when it comes to highly loaded systems. As it has to wait for all NGINX worker processes to finish before reloading, there's a period where the system won't be processing at the same capacity as normal.
Here's how our scenario will look:
