Summary

PHP-FPM, PHP FastCGI Process Manager, is a part of PHP package in OpenBSD packages nowadays.
So installing PHP (php-?.? due to the version) comes with php??_fpm automatically 💃
This post will show you how to set it up.

Environment

OS: OpenBSD 7.0 amd64
PHP: 8.0

✿ ✿ ✿

Tutorial

Installation

The first step is to install the PHP package:

$ doas pkg_add php
Ambiguous: choose package for php
a   0: <None>
    1: php-7.3.33
    2: php-7.4.27
    3: php-8.0.14
Your choice:

I chose "3" because it's longer supported term due to each support term of the PHP versions.

The output was:

php-8.0.14:femail-1.0p1: ok
php-8.0.14:femail-chroot-1.0p3: ok
php-8.0.14:argon2-20190702: ok
php-8.0.14:libsodium-1.0.18p1: ok
php-8.0.14:libxml-2.9.12: ok
php-8.0.14:oniguruma-6.9.7.1: ok
php-8.0.14: ok
Running tags: ok
The following new rcscripts were installed: /etc/rc.d/php80_fpm
See rcctl(8) for details.
New and changed readme(s):
    /usr/local/share/doc/pkg-readmes/femail-chroot
    /usr/local/share/doc/pkg-readmes/php-8.0

Then these directories/files were made:

$ ls /etc/php*
/etc/php-8.0.ini  /etc/php-fpm.conf

/etc/php-8.0:

/etc/php-8.0.sample:
opcache.ini

/etc/php-fpm.d:

Well, the .ini file(s) in /etc/php-8.0.sample are PHP extensions.
According to necessity, copy each of them to /etc/php-8.0/ to activate the extensions:

$ doas ln -sf /etc/php-8.0.sample/%target-ini-files% /etc/php-8.0/

Also edit /etc/php-8.0.ini as needed.
For example:

  ; Maximum allowed size for uploaded files.
  ; http://php.net/upload-max-filesize
- upload_max_filesize = 2M
+ upload_max_filesize = 5M

Besides, the manual is also installed as /usr/local/share/doc/pkg-readmes/php-8.0 which declares:

The main OpenBSD php packages include php-fpm, FastCGI Process Manager.
This manages pools of FastCGI processes: starts/restarts them and
maintains a minimum and maximum number of spare processes as
configured. You can use rcctl(8) to enable php-fpm at boot,
and start it at runtime:

rcctl enable php80_fpm
rcctl start php80_fpm

OK. We're ready.
Let's start daemon:

$ doas rcctl enable php80_fpm

It appended a line to /etc/rc.conf.local:

+ pkg_scripts=php80_fpm

OK. It's time to start the daemon:

$ doas rcctl start php80_fpm
php80_fpm(ok)

Usage

Next, we need to prepare a web server.
Let's edit /etc/httpd.conf to add fastcgi socket in SERVERS sections like this:

types {
    include "/usr/share/misc/mime.types"
}

ext_addr="egress"

server "default" {
    listen on $ext_addr port 80

    root "/htdocs"
    directory index index.php

    location "/*.php" { 
        fastcgi socket "/run/php-fpm.sock"
    }
    location "/*.php[/?]*" { 
        fastcgi socket "/run/php-fpm.sock"
    } 
}

Note that chroot works in this context.
Therefore, fastcgi socket "/run/php-fpm.sock" in /etc/httpd.conf actually means fastcgi socket "/var/www/run/php-fpm.sock".
This is the same to that root "/htdocs" means "/var/www/htdocs".

Testing

Let's make /var/www/htdocs/index.php for testing like this:

# echo "<?php phpinfo(); ?>" > /var/www/htdocs/index.php
# # delete the file above afterwards as needed

Then browsing your host will show you the whole phpinfo!