How To Set Up Apache2 With mod_fcgid And PHP5 On CentOS 6.2

Version 1.0
Author: Falko Timme <ft [at] falkotimme [dot] com>
Follow me on Twitter
Last edited 04/03/2012

This tutorial describes how you can install Apache2 with mod_fcgid and PHP5 on CentOS 6.2. mod_fcgid is a compatible alternative to the older mod_fastcgi. It lets you execute PHP scripts with the permissions of their owners instead of the Apache user.

I do not issue any guarantee that this will work for you!

1 Preliminary Note

I'm using a CentOS 6.2 server in this tutorial with the hostname server1.example.com and the IP address 192.168.0.100.

I will create two Apache vhosts in this tutorial, www.example1.com and www.example2.com, to demonstrate the usage of mod_fcgid.

Before we start, make sure that SELinux is disabled. Edit /etc/selinux/config and set SELINUX=disabled:

vi /etc/selinux/config

# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
#     enforcing - SELinux security policy is enforced.
#     permissive - SELinux prints warnings instead of enforcing.
#     disabled - No SELinux policy is loaded.
SELINUX=disabled
# SELINUXTYPE= can take one of these two values:
#     targeted - Targeted processes are protected,
#     mls - Multi Level Security protection.
SELINUXTYPE=targeted

Afterwards we must reboot the system:

reboot

2 Installing Apache2/mod_fcgi/PHP5

mod_fcgid is not available in the official CentOS repositories, but there's a package in the EPEL repository. We enable the repository as follows:

rpm --import https://fedoraproject.org/static/0608B895.txt
wget http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-7.noarch.rpm
rpm -ivh epel-release-6-7.noarch.rpm

yum install yum-priorities

Edit /etc/yum.repos.d/epel.repo...

vi /etc/yum.repos.d/epel.repo

... and add the line priority=10 to the [epel] section:

[epel]
name=Extra Packages for Enterprise Linux 6 - $basearch
#baseurl=http://download.fedoraproject.org/pub/epel/6/$basearch
mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-6&arch=$basearch
failovermethod=priority
enabled=1
priority=10
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
[...]

Afterwards we can install Apache2, mod_fcgid, and PHP5:

yum install httpd mod_fcgid php-cli

If Apache2 was already installed with PHP5 as an Apache module, disable the PHP5 module now - open /etc/httpd/conf.d/php.conf...

vi /etc/httpd/conf.d/php.conf

... and comment out everything in that file:

#
# PHP is an HTML-embedded scripting language which attempts to make it
# easy for developers to write dynamically generated webpages.
#
#<IfModule prefork.c>
#  LoadModule php5_module modules/libphp5.so
#</IfModule>
#<IfModule worker.c>
#  LoadModule php5_module modules/libphp5-zts.so
#</IfModule>
#
# Cause the PHP interpreter to handle files with a .php extension.
#
#AddHandler php5-script .php
#AddType text/html .php
#
# Add index.php to the list of files that will be served as directory
# indexes.
#
#DirectoryIndex index.php
#
# Uncomment the following line to allow PHP to pretty-print .phps
# files as PHP source code:
#
#AddType application/x-httpd-php-source .phps

Then we create the system startup links for Apache and start it:

chkconfig --levels 235 httpd on
/etc/init.d/httpd restart

Next we open /etc/php.ini...

vi /etc/php.ini

... and uncomment the line cgi.fix_pathinfo=1:

[...]
; cgi.fix_pathinfo provides *real* PATH_INFO/PATH_TRANSLATED support for CGI.  PHP's
; previous behaviour was to set PATH_TRANSLATED to SCRIPT_FILENAME, and to not grok
; what PATH_INFO is.  For more information on PATH_INFO, see the cgi specs.  Setting
; this to 1 will cause PHP CGI to fix its paths to conform to the spec.  A setting
; of zero causes PHP to behave as before.  Default is 1.  You should fix your scripts
; to use SCRIPT_FILENAME rather than PATH_TRANSLATED.
; http://www.php.net/manual/en/ini.core.php#ini.cgi.fix-pathinfo
cgi.fix_pathinfo=1
[...]

Open /etc/httpd/conf.d/fcgid.conf...

vi /etc/httpd/conf.d/fcgid.conf

... and add the line PHP_Fix_Pathinfo_Enable 1 at the end:

[...]
PHP_Fix_Pathinfo_Enable 1

Then reload Apache:

/etc/init.d/httpd reload

3 Creating Vhosts For www.example1.com And www.example2.com

I will now create two vhosts, www.example1.com (with the document root /var/www/web1/web) and www.example2.com (with the document root /var/www/web2/web). www.example1.com will be owned by the user and group web1, and www.example2.com by the user and group web2.

First we create the users and groups:

groupadd web1
groupadd web2
useradd -s /bin/false -d /var/www/web1 -m -g web1 web1
useradd -s /bin/false -d /var/www/web2 -m -g web2 web2
chmod 755 /var/www/web1
chmod 755 /var/www/web2

Then we create the document roots and make them owned by the users/groups web1 resp. web2:

mkdir -p /var/www/web1/web
chown web1:web1 /var/www/web1/web
mkdir -p /var/www/web2/web
chown web2:web2 /var/www/web2/web

We will run PHP using suExec; suExec's document root is /var/www, as the following command shows:

/usr/sbin/suexec -V

[root@server1 ~]# /usr/sbin/suexec -V
 -D AP_DOC_ROOT="/var/www"
 -D AP_GID_MIN=100
 -D AP_HTTPD_USER="apache"
 -D AP_LOG_EXEC="/var/log/httpd/suexec.log"
 -D AP_SAFE_PATH="/usr/local/bin:/usr/bin:/bin"
 -D AP_UID_MIN=500
 -D AP_USERDIR_SUFFIX="public_html"
[root@server1 ~]#

Therefore we cannot call the PHP binary (/usr/bin/php-cgi) directly because it is located outside suExec's document root. As suExec does not allow symlinks, the only way to solve the problem is to create a wrapper script for each web site in a subdirectory of /var/www; the wrapper script will then call the PHP binary /usr/bin/php-cgi. The wrapper script must be owned by the user and group of each web site, therefore we need one wrapper script for each web site. I'm going to create the wrapper scripts in subdirectories of /var/www/php-fcgi-scripts, e.g. /var/www/php-fcgi-scripts/web1 and /var/www/php-fcgi-scripts/web2.

mkdir -p /var/www/php-fcgi-scripts/web1
mkdir -p /var/www/php-fcgi-scripts/web2

vi /var/www/php-fcgi-scripts/web1/php-fcgi-starter

#!/bin/sh
PHPRC=/etc/
export PHPRC
export PHP_FCGI_MAX_REQUESTS=5000
export PHP_FCGI_CHILDREN=8
exec /usr/bin/php-cgi

vi /var/www/php-fcgi-scripts/web2/php-fcgi-starter

#!/bin/sh
PHPRC=/etc/
export PHPRC
export PHP_FCGI_MAX_REQUESTS=5000
export PHP_FCGI_CHILDREN=8
exec /usr/bin/php-cgi

The PHPRC line contains the directory where the php.ini file is located (i.e., /etc/ translates to /etc/php.ini). PHP_FCGI_MAX_REQUESTS is the maximum number of requests before an fcgid process is stopped and a new one is launched. PHP_FCGI_CHILDREN defines the number of PHP children that will be launched.

The php-fcgi-starter scripts must be executable, and they (and the directories they are in) must be owned by the web site's user and group:

chmod 755 /var/www/php-fcgi-scripts/web1/php-fcgi-starter
chmod 755 /var/www/php-fcgi-scripts/web2/php-fcgi-starter
chown -R web1:web1 /var/www/php-fcgi-scripts/web1
chown -R web2:web2 /var/www/php-fcgi-scripts/web2

Now we create the Apache vhosts for www.example1.com and www.example2.com. Add the following two vhosts at the end of /etc/httpd/conf/httpd.conf:

vi /etc/httpd/conf/httpd.conf

[...]
NameVirtualHost *:80
<VirtualHost *:80>
  ServerName www.example1.com
  ServerAlias example1.com
  ServerAdmin webmaster@example1.com
  DocumentRoot /var/www/web1/web/
  <IfModule mod_fcgid.c>
    SuexecUserGroup web1 web1
    <Directory /var/www/web1/web/>
      Options +ExecCGI
      AllowOverride All
      AddHandler fcgid-script .php
      FCGIWrapper /var/www/php-fcgi-scripts/web1/php-fcgi-starter .php
      Order allow,deny
      Allow from all
    </Directory>
  </IfModule>
  # ErrorLog /var/log/apache2/error.log
  # CustomLog /var/log/apache2/access.log combined
  ServerSignature Off
</VirtualHost>
<VirtualHost *:80>
  ServerName www.example2.com
  ServerAlias example2.com
  ServerAdmin webmaster@example2.com
  DocumentRoot /var/www/web2/web/
  <IfModule mod_fcgid.c>
    SuexecUserGroup web2 web2
    <Directory /var/www/web2/web/>
      Options +ExecCGI
      AllowOverride All
      AddHandler fcgid-script .php
      FCGIWrapper /var/www/php-fcgi-scripts/web2/php-fcgi-starter .php
      Order allow,deny
      Allow from all
    </Directory>
  </IfModule>
  # ErrorLog /var/log/apache2/error.log
  # CustomLog /var/log/apache2/access.log combined
  ServerSignature Off
</VirtualHost>

Make sure you fill in the right paths (and the correct user and group in the SuexecUserGroup lines).

Reload Apache afterwards:

/etc/init.d/httpd reload