How to select PHP version 5 and 7 per virtualhost in Apache 2.4 on Debian?

Question

Would it be possible to run PHP 7 and PHP 5 simultaneously in Apache 2.4 on Debian 9? I would like to be able to select the PHP version I wish to use per virtualhost. I believe this would be useful considering that some of my websites still use deprecated PHP features. This allows me to perform upgrades per site. How do I achieve something like this?

For example

<VirtualHost *:80>
   ServerAdmin webmaster@localhost
   ServerName mywebsite.com
   DocumentRoot /var/www/mywebsite.com

   # UsePHP 7
</virtualHost>

And

<VirtualHost *:80>
   ServerAdmin webmaster@localhost
   ServerName mywebsite2.com
   DocumentRoot /var/www/mywebsite2.com

   # UsePHP 5
</virtualHost>

Answer 1

Let's start from beginning. I assume that you would prefer to use php-fpm instead of Apache module.

First install apache:

sudo apt-get update
sudo apt-get install apache2

Next install multiple PHP:

Debian 9:
Install PHP 7:

sudo apt-get install php7.0-cli php7.0-fpm php-pear libapache2-mod-fastcgi

Configure repositories:

sudo apt-get install apt-transport-https
sudo curl https://packages.sury.org/php/apt.gpg | apt-key add -
sudo echo 'deb https://packages.sury.org/php/ stretch main' > /etc/apt/sources.list.d/deb.sury.org.list
sudo apt-get update

Install PHP 5:

sudo apt-get install php5.6-cli php5.6-fpm

Debian 8:
Install PHP 5:

sudo apt-get install php5 php5-fpm php-pear libapache2-mod-fastcgi

Configure repositories:
Edit /etc/apt/sources.list and add the following lines to the end of file:

deb http://packages.dotdeb.org jessie all
deb-src http://packages.dotdeb.org jessie all

Install GPG key:

wget https://www.dotdeb.org/dotdeb.gpg
sudo apt-key add dotdeb.gpg
sudo apt-get update

Install PHP 7:

sudo apt-get install php7.0 php7.0-fpm

Next switch from prefork and enable necessary modules:
For Debian 8:

a2dismod php5 mpm_prefork

For Debian 9:

a2dismod php7 mpm_prefork

Next for both:

a2enmod actions fastcgi alias proxy_fcgi mpm_worker
systemctl restart apache2

Change content of /etc/apache2/mods-enabled/fastcgi.conf to the following one:

<IfModule !mod_fastcgi.c>
    AddHandler fcgid-script fcg fcgi fpl
</IfModule>
<IfModule mod_fastcgi.c>
    <Directory /usr/lib/cgi-bin>
        Require all granted
    </Directory>
</IfModule>

Now create document root folders for websites:

mkdir -p /var/www/example.com/public_html
mkdir -p /var/www/test.com/public_html

Add sys users for these websites:

sudo useradd example --home-dir /var/www/example.com
sudo useradd test --home-dir /var/www/test.com

Configure ownership:

sudo chown -R example.example /var/www/example.com
sudo chown -R test.test /var/www/test.com

For example website example.com will use PHP 5 and website test.com will use PHP 7.

Create configuration files for websites:
Website on PHP 5:

touch /etc/apache2/sites-available/example.com.conf
ln -s /etc/apache2/sites-available/example.com.conf /etc/apache2/sites-enabled/example.com.conf
cat /etc/apache2/sites-available/example.com.conf
<VirtualHost *:80>

        ServerAdmin webmaster@localhost
        ServerName example.com
        ServerAlias www.example.com
        DocumentRoot /var/www/example.com/public_html
        ErrorLog ${APACHE_LOG_DIR}/error.log
        CustomLog ${APACHE_LOG_DIR}/access.log combined

        <IfModule mod_fastcgi.c>
            AddType application/x-httpd-fastphp5 .php
            Action application/x-httpd-fastphp5 /php5-fcgi
            Alias /php5-fcgi /usr/lib/cgi-bin/php5-fcgi-example.com
            FastCgiExternalServer /usr/lib/cgi-bin/php5-fcgi-example.com -socket /var/run/php5-fpm-example.com.sock -pass-header Authorization
        </IfModule>

</VirtualHost>

Website on PHP 7:

touch /etc/apache2/sites-available/test.com.conf
ln -s /etc/apache2/sites-available/test.com.conf /etc/apache2/sites-enabled/test.com.conf
cat /etc/apache2/sites-available/test.com.conf
<VirtualHost *:80>

        ServerAdmin webmaster@localhost
        ServerName test.com
        ServerAlias www.test.com
        DocumentRoot /var/www/test.com/public_html
        ErrorLog ${APACHE_LOG_DIR}/error.log
        CustomLog ${APACHE_LOG_DIR}/access.log combined

        <IfModule mod_fastcgi.c>
                AddHandler php7-fcgi .php
                Action php7-fcgi /php7-fcgi virtual
                Alias /php7-fcgi /usr/lib/cgi-bin/php7-fcgi-test.com
                FastCgiExternalServer /usr/lib/cgi-bin/php7-fcgi-test.com -socket /var/run/php/php7.0-fpm-test.com.sock -pass-header Authorization
        </IfModule>

</VirtualHost>

Create pool configs (I used the following):
Website on PHP 5:

cat /etc/php5/fpm/pool.d/example.com.conf
[example.com]
user = example
group = example
listen = /var/run/php5-fpm-example.com.sock
listen.owner = www-data
listen.group = www-data
php_admin_value[disable_functions] = exec,passthru,shell_exec,system
php_admin_flag[allow_url_fopen] = off
pm = dynamic
pm.max_children = 5
pm.start_servers = 2
pm.min_spare_servers = 1
pm.max_spare_servers = 3
chdir = /

Website on PHP 7:

cat /etc/php/7.0/fpm/pool.d/test.com.conf
[test.com]
user = test
group = test
listen = /var/run/php/php7.0-fpm-test.com.sock
listen.owner = www-data
listen.group = www-data
php_admin_value[disable_functions] = exec,passthru,shell_exec,system
php_admin_flag[allow_url_fopen] = off
pm = dynamic
pm.max_children = 5
pm.start_servers = 2
pm.min_spare_servers = 1
pm.max_spare_servers = 3
chdir = /

Restart apache and php-fpm services:

sudo systemctl restart apache2 php5-fpm php7.0-fpm

Enjoy!

Answer 2

The answer by @elvis-plesky is really detailled. But Apache suggests the usage of mod_proxy_fcgi:

With the release of apache httpd 2.4 upon an unsuspecting populace, we have gained some very neat functionality regarding apache and php: the ability to run PHP as a fastCGI process server, and address that fastCGI server directly from within apache, via a dedicated proxy module (mod_proxy_fcgi.)

Here are the steps to setup two vhosts with different PHP versions for Debian 10 using Apache's mod_proxy_fcgi and php-fpm.

Configure repositories:

sudo apt-get install apt-transport-https
sudo curl https://packages.sury.org/php/apt.gpg | apt-key add -
sudo echo 'deb https://packages.sury.org/php/ stretch main' > /etc/apt/sources.list.d/deb.sury.org.list
sudo apt-get update

Install needed PHP versions:

sudo apt-get install php5.6-cli php5.6-fpm php7.3-cli php7.3-fpm

Configure php5.6-fpm in /etc/apache2/conf-available/php5.6-fpm.conf:

<IfModule !mod_php5.c>
<IfModule proxy_fcgi_module>
    # Enable http authorization headers
    <IfModule setenvif_module>
        SetEnvIfNoCase ^Authorization$ "(.+)" HTTP_AUTHORIZATION=$1
    </IfModule>

    <FilesMatch ".+\.ph(ar|p|tml)$">
        SetHandler "proxy:unix:/run/php/php5.6-fpm.sock|fcgi://php56.localhost"
    </FilesMatch>
    # Deny access to files without filename (e.g. '.php')
    <FilesMatch "^\.ph(ar|p|ps|tml)$">
        Require all denied
    </FilesMatch>
</IfModule>
</IfModule>

Configure php7.3-fpm in /etc/apache2/conf-available/php7.3-fpm.conf:

<IfModule !mod_php7.c>
<IfModule proxy_fcgi_module>
    # Enable http authorization headers
    <IfModule setenvif_module>
        SetEnvIfNoCase ^Authorization$ "(.+)" HTTP_AUTHORIZATION=$1
    </IfModule>

    <FilesMatch ".+\.ph(ar|p|tml)$">
        SetHandler "proxy:unix:/run/php/php7.3-fpm.sock|fcgi://php73.localhost"
    </FilesMatch>
    # Deny access to files without filename (e.g. '.php')
    <FilesMatch "^\.ph(ar|p|ps|tml)$">
        Require all denied
    </FilesMatch>
</IfModule>
</IfModule>

Now add a virtual host that uses PHP 5.6:

<VirtualHost *:80>
    ServerName test-php56.localhost
    DocumentRoot "/var/www/test-php56/"
    # use php 5.6
    <FilesMatch ".+\.ph(ar|p|tml)$">
        SetHandler "proxy:unix:/run/php/php5.6-fpm.sock|fcgi://php56.localhost"
    </FilesMatch>
</VirtualHost>

And a virtual host that uses PHP 7.3:

<VirtualHost *:80>
    ServerName test-php73.localhost
    DocumentRoot "/var/www/test-php73/"
    # use php 7.3
    <FilesMatch ".+\.ph(ar|p|tml)$">
        SetHandler "proxy:unix:/run/php/php7.3-fpm.sock|fcgi://php73.localhost"
    </FilesMatch>
</VirtualHost>

Activate the correct Apache module and the configs:

sudo a2enmod proxy_fcgi
sudo a2enconf php5.6-fpm
sudo a2enconf php7.3-fpm
sudo systemctl restart apache2 php5.6-fpm php7.3-fpm

The default configuration of the FPM pools should be correct already.

---

Important:

This change will break old virtual hosts. You need to reconfigure all your virtual hosts and add the FilesMatch block which your project needs. For example if your project needs php 7.4 then you first need to install the fpm package:

sudo apt-get install php7.4-fpm
sudo a2enconf php7.4-fpm
sudo systemctl restart apache2 php7.4-fpm

Then add this section to your vhost config:

...
# use php 7.4
<FilesMatch ".+\.ph(ar|p|tml)$">
    SetHandler "proxy:unix:/run/php/php7.4-fpm.sock|fcgi://php74.localhost"
</FilesMatch>

Then restart apache service apache2 restart.