I installed hestiaCP with Web Server = nginx and Backend Server = php-fpm, believing that that was the way to serve web pages using the least amount of RAM.
I’ve tried to apply the info in Setting up Perl FastCGI with Nginx - Nginx Library to my hestiaCP vps, without success. A search of topics here does not indicate that anyone’s ever done any better (is that possible?).
Can anyone help? Should I quit while I’m behind and try apache?
hestiaCP would not install for me under OpenVZ/Debian10 when I told it to include apache, so I’m back to where I was…
How can I get NGINX’s back end to pass variables to a Perl script, run it, and push its output via nginx/http?
The php-fpm Backend Templates don’t look enough like the nginx Web Templates (Edit Web Domain, Advanced…) for me to guess what to try changing next…
You are referring to a 12 year tutorial. Sadly I have never used Perl in combination with both Apache2 / Nginx
There is an issue about it
I can remember a user was talking about but can’t find it any more on Discord… But I am really not wanting to investigate x hours into it with out any compensation…
Similar to the person who posted that link you provided Add Perl/CGI Support to HestiaCP I’ve found no better info than that 12 year old tutorial, which is either the definitive info or else it confounds the notion that the internet is its own best resource…
I have a shared hosting provider whose web server announces itself as nginx but the .htaccess (for password protection) and cgi-bin (subdir of web root) work same as they had for 20 years under apache.
BUT now my hestia is back to Web Server = nginx and Backend Server = php-fpm (…seemed like the attempted installs including apache maybe got hung up on an apt-get?), so I’m back to the 12-yr-old clue.
Seems like once someone comes up with the right template (modification), it should be similar to enabling password-protected web directories (…iirc the first pkg, libfcgi-perl, was already installed), just another drop-box selection…
I started over, on a KVM vps, which, unlike OpenVZ, lets me enable a swap file, which means plenty of (effective) RAM to run apache, so my scripts run now. I never did figure out how to make that happen w/o apache. 
You can also try using my project which is similar to php-fpm, but works with everything that supports FastCGI startup protocol (including Perl’s CGI::Fast module): GitHub - vdudouyt/std-fpm: A language-agnostic FastCGI process manager
Personally, I’m using it with Nginx web server in production.