Upgrading one of the oldest components in Cloudflare’s software stack

Cloudflare's new NGINX upgrade mechanism allows for a more efficient and less memory-intensive upgrade process. The standard upgrade mechanism used by NGINX is not suitable at Cloudflare's scale, as it doubles up memory requirements during the release period. To address this issue, Cloudflare customized the NGINX upgrade mechanism to control individual workers rather than treating the entire instance (master + workers) as one. This enables them to start all the workers whilst all the previous ones are still running, reducing memory usage and speeding up the upgrade process.