Using PHP with mod_fcgid

1. Speed
   mod_fcgid seems to be as fast as the traditional mod_php Apache module. However, it also allows to be run on a multi threaded Apache server. For various reasons this still does not work reliable with mod_php4 / mod_php5.
2. Configuration flexibility
   With mod_fcgid it is possible to run many different PHP versions on the same server, and even with multiple different users.

Disadvantages of mod_fcgid

1. Installation is more complex Installation of PHP using mod_fcgid is probably more difficult than setting up mod_php5, mainly because there is only a few documentation about it that can be found. However, since you found this document, you may be lucky...

1. php5-cgi
   This is the CGI binary of PHP5. It was compiled with FCGI support and works perfectly together with mod_fcgid.
2. libapache2-mod-fcgid
   This is the FCGID
3. module apache2-mpm-worker
   This is the multi threaded multi-processing module (MPM) for Apache2. It replaces apache2-mpm-prefork with is a single-threaded MPM and is required by mod_php4 / mod_php5. Of course these packages must also be removed. Keep in mind that you may want to make a backup of your current php.ini, because php5-cgi will set up a new configuration file.
   # apt-get -u install php5-cgi libapache2-mod-fcgid apache2-mpm-worker

1. Remove mod_php4 / mod_php5 if not already done 

   # a2dismod php4
   # a2dismod php5

2. Enable mod_actions and mod_fcgid 

   # a2enmod actions
   # a2enmod fcgid

3. Raise the communication timeout (= maximum execution time) for FCGI applications in /etc/apache2/mods-enabled/fcgid.conf by adding the “IPCCommTimeout” directive 

   <IfModule mod_fcgid.c>
       AddHandler fcgid-script .fcgi
       SocketPath /var/lib/apache2/fcgid/sock
       
       # Communication timeout: Default value is 20 seconds
       IPCCommTimeout 60
       
       # Connection timeout: Default value is 3 seconds
       
       #IPCConnectTimeout 3
   </IfModule>

4. Create a new file /etc/apache2/conf.d/php-fcgid.conf: 

   <IfModule !mod_php4.c>
   <IfModule !mod_php4_filter.c>
   <IfModule !mod_php5.c>
   <IfModule !mod_php5_filter.c>
   <IfModule !mod_php5_hooks.c>
   <IfModule mod_actions.c>
   <IfModule mod_alias.c>
   <IfModule mod_mime.c>
   <IfModule mod_fcgid.c>
       # Path to php.ini – defaults to /etc/phpX/cgi
       DefaultInitEnv PHPRC=/etc/php5/cgi
       
       # Number of PHP childs that will be launched. Leave undefined to let PHP decide.
       #DefaultInitEnv PHP_FCGI_CHILDREN 3
       
       # Maximum requests before a process is stopped and a new one is launched
       #DefaultInitEnv PHP_FCGI_MAX_REQUESTS 5000
       
       # Define a new handler "php-fcgi" for ".php" files, plus the action that must follow
       AddHandler php-fcgi .php
       Action php-fcgi /fcgi-bin/php-fcgi-wrapper
       
       # Define the MIME-Type for ".php" files
       AddType application/x-httpd-php .php
       
       # Define alias "/fcgi-bin/". The action above is using this value, which means that
       # you could run another "php5-cgi" command by just changing this alias
       Alias /fcgi-bin/ /var/www/fcgi-bin.d/php5-default/
       
       # Turn on the fcgid-script handler for all files within the alias "/fcgi-bin/"
       <Location /fcgi-bin/>
           SetHandler fcgid-script
           Options +ExecCGI
       </Location>
   </IfModule>
   </IfModule>
   </IfModule>
   </IfModule>
   </IfModule>
   </IfModule>
   </IfModule>
   </IfModule>
   </IfModule>

5. Next, create the directory which is chosen by the alias, and put in a symlink to the php5-cgi binary 

   # mkdir /var/www/fcgi-bin.d/php5-default
   # ln -s /usr/bin/php5-cgi /var/www/fcgi-bin.d/php5-default/php-fcgi-wrapper

6. Finally, restart Apache 

   # /etc/init.d/apache2 restart

It is also possible to run different versions of PHP, even with different users. 

1. Enable mod_suexec 

   # a2enmod suexec

2. Create a new user 

   # adduser <username>

3. For every instance of PHP, create a new subdirectory in /var/www/fcgi-bin.d/ 

   # mkdir /var/www/fcgi-bin.d/php<version>-<username>/

4. Instead of creating a symlink, this time you need to add a new file “php-fcgi-wrapper” inside this directory 

   #!/bin/sh
   # Wrapper for PHP-fcgi
   # This wrapper can be used to define settings before launching the PHP-fcgi binary.
   
   # Define the path to php.ini. This defaults to /etc/phpX/cgi.
   #export PHPRC=/var/www/fcgi-bin.d/php5-web01/phprc
   #export PHPRC=/etc/php5/cgi
   
   # Define the number of PHP childs that will be launched. Leave undefined to let PHP decide.
   #export PHP_FCGI_CHILDREN=3
   
   # Maximum requests before a process is stopped and a new one is launched
   #export PHP_FCGI_MAX_REQUESTS=5000
   
   # Launch the PHP CGI binary
   # This can be any other version of PHP which is compiled with FCGI support.
   exec /usr/bin/php5-cgi

1. Make this script executable and change the user appropriately 

   # chmod a+x /var/www/fcgi-bin.d/php<version>-<username>/php-fcgi-wrapper
   # chown <user>:<group> /var/www/fcgi-bin.d/php<version>-<username>/php-fcgi-wrapper

2. Modify the Apache configuration, e.g. in /etc/apache2/sites-enabled/web01 

   <VirtualHost *:80>
       Servername web01.myserver.com
       DocumentRoot /var/www/websites/web01/
       SuexecUserGroup <user> <group>
       Action php-fcgi /fcgi-bin/php-fcgi-wrapper
       Alias /fcgi-bin/ /var/www/fcgi-bin.d/php<version>-<username>/
   </VirtualHost>

   Notice: It is important that user and group are owned by the same user and group as defined for the wrapper script above. 

3. Restart Apache 

   # /etc/init.d/apache2 restart

Further reading

[1] Website of mod_fcgid: <link http: fastcgi.coremail.cn>fastcgi.coremail.cn

FAQ

How fast is it? 

Compared to mod_php5 the speed seems to be almost equal, probably just a little bit slower. 

Can I turn off the PHP parser for a specific directory? 

Of course! You can simply disable the parser for directories. This is very useful for example to use WebDAV for editing PHP files. Using mod_php5 these files would be sent as plain HTML output: 

<Location /dav/>
    RemoveHandler .php
</Location>

ChangeLog

Changes in version 1.0 

1. Initial version 

About the author

Michael Stucki is the leader of the TYPO3 core team. He lives close to Basel / Switzerland. When he is not developing, he likes doing sports and travel around. Michael is working for snowflake productions, where this document was initially written as a help guide for their customers.