How to safely rebuild nginx on Ubuntu 16.04?

Question

Nginx

There is a VDS with Ubuntu 16.04 running Vesta CP. VDS is used as a web server (nginx + php-fpm). You need to rebuild nginx by adding a new module. By a secure build, I mean one where you can easily revert to the old nginx and not lose your configs. The server can be stopped. How to act? What to back up/rename?

Answer 1

which nginx, this is a backup, the configs will not be affected during the build
nginx -V will show the current build there, just add the modules and that's it

Answer 2

The easiest and "safest" way is to build Nginx on another machine with the necessary parameters, make a package out of it and test its performance. It will be 100% safe.
A little more dangerous (including from the point of view of "crap the server") is to build Nginx somewhere aside (for example, in the home folder) and run it manually from there. If everything works as it should, you can stick it in its rightful place.
An alternative and safe option is to download Nginx already built by someone with the module you need.
PS Configs are usually not overwritten (in my memory this has never happened), but this should not be a reason not to backup them.