Example PHP-FPM container with Apache on host

This is a tiny example on how to setup a web server with Apache running on the host, and PHP-FPM running in a container. This can be handy for running multiple PHP versions on a single server, or running different sites that need different PHP versions.

Setup

Build the container

sudo docker build -t fpm-example .

Run the container

sudo docker run -d -v $(pwd)/html:/var/www/html -p 9001:9000 --name fpm1 fpm-example

-d for detached mode
-v $(pwd)/html:/var/www/html to map host html folder to container /var/www/html. $(pwd) because the host path must be absolute.
-p to map 9001 host port to container 9000 port. PHP-FPM runs on port 9000 inside the container. If you need other FPMs to run, change 9001 with whatever free port.
--name fpm1 so we can easily pick that container when running commands.

Apache

Enable some mods with sudo a2enmod proxy proxy_fcgi and sudo systemctl restart apache2

Virtual Host

Create a fpm1.conf in /etc/apache2/sites-available.

The important part is the ProxyPassMatch rule. It defines what process to execute the PHP files on.

Notice the 9001 which is the port we chose when mapping the container port.
/var/www/html is also important, it tels PHP-FPM where the file is located on its side. Apache2 and PHP-FPM must both have access to the files, but PHP-FPM has access to them through a mounted volume inside the docker container, which has a different path.

Of course the DocumentRoot path must be changed to match your path.

<<VirtualHost *:80>
    ServerName fpm1.local

    DocumentRoot /home/louwii/Dev/fpm/html

    ProxyPassMatch ^/(.*\.php(/.*)?)$ fcgi://127.0.0.1:9001/var/www/html/$1

    <Directory /home/louwii/Dev/fpm/html>
        Options -Indexes +FollowSymLinks +MultiViews
        AllowOverride All
        Require all granted
        DirectoryIndex index.php
    </Directory>

    ErrorLog ${APACHE_LOG_DIR}/fpm1-error.log
</VirtualHost>

Run sudo a2ensite fpm1 and sudo systemctl reload apache2.

Add this line into your /etc/hosts file

127.0.0.1    fpm1.local

Done!

Just go to http://fpm1.local/ and it should just work.

Debug

Handy commands for debugging

sudo docker logs -f fpm1 to get the container logs.