Nginx and PHP-FastCGI on Ubuntu 11.04 (Natty)

The nginx web server is a fast, lightweight server designed to efficiently handle the needs of both low and high traffic websites. Although commonly used to serve static content, it’s quite capable of handling dynamic pages as well. This guide will help you get nginx up and running with PHP via FastCGI on your Ubuntu 11.04 (Natty) Linode.

It is assumed that you’ve already followed the steps outlined in our Setting Up and Securing a Compute Instance. These steps should be performed via a root login to your Linode over SSH.

Set the Hostname

Before you begin installing and configuring the components described in this guide, please make sure you’ve followed our instructions for setting your hostname. Issue the following commands to make sure it is set properly:

hostname
hostname -f

The first command should show your short hostname, and the second should show your fully qualified domain name (FQDN).

Install Required Packages

Issue the following commands to update your system and install the nginx web server, PHP, and compiler tools:

apt-get update
apt-get upgrade
apt-get install nginx php5-cli php5-cgi spawn-fcgi psmisc

Configure Virtual Hosting

Create Directories

In this guide, the domain “example.com” is used as an example site. You should substitute your own domain name in the configuration steps that follow. First, create directories to hold content and log files:

mkdir -p /srv/www/www.example.com/public_html
mkdir /srv/www/www.example.com/logs
chown -R www-data:www-data /srv/www/www.example.com

UNIX Sockets Configuration Example

Next, you’ll need to define the site’s virtual host file. This example uses a UNIX socket to connect to fcgiwrap. Be sure to change all instances of “example.com” to your domain name.

File: /etc/nginx/sites-available/www.example.com

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server { server_name www.example.com example.com; access_log /srv/www/www.example.com/logs/access.log; error_log /srv/www/www.example.com/logs/error.log; root /srv/www/www.example.com/public_html; location / { index index.html index.htm; } location ~ \.php$ { include /etc/nginx/fastcgi_params; fastcgi_pass unix:/var/run/php-fastcgi/php-fastcgi.socket; fastcgi_index index.php; fastcgi_param SCRIPT_FILENAME /srv/www/www.example.com/public_html$fastcgi_script_name; } }

Create a file named /usr/bin/php-fastcgi with the following contents:

File: /usr/bin/php-fastcgi

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#!/bin/bash FASTCGI_USER=www-data FASTCGI_GROUP=www-data SOCKET=/var/run/php-fastcgi/php-fastcgi.socket PIDFILE=/var/run/php-fastcgi/php-fastcgi.pid CHILDREN=6 PHP5=/usr/bin/php5-cgi /usr/bin/spawn-fcgi -s $SOCKET -P $PIDFILE -C $CHILDREN -u $FASTCGI_USER -g $FASTCGI_GROUP -f $PHP5

Make it executable by issuing the following command:

chmod +x /usr/bin/php-fastcgi

TCP Sockets Configuration Example

Alternately, you may wish to use TCP sockets instead. If so, modify your nginx virtual host configuration file to resemble the following example. Again, make sure to replace all instances of “example.com” with your domain name.

File: /etc/nginx/sites-available/www.example.com

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server { server_name www.example.com example.com; access_log /srv/www/www.example.com/logs/access.log; error_log /srv/www/www.example.com/logs/error.log; root /srv/www/www.example.com/public_html; location / { index index.html index.htm; } location ~ \.php$ { include /etc/nginx/fastcgi_params; fastcgi_pass 127.0.0.1:9000; fastcgi_index index.php; fastcgi_param SCRIPT_FILENAME /srv/www/www.example.com/public_html$fastcgi_script_name; } }

Create a file named /usr/bin/php-fastcgi with the following contents:

File: /usr/bin/php-fastcgi

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#!/bin/bash FASTCGI_USER=www-data FASTCGI_GROUP=www-data ADDRESS=127.0.0.1 PORT=9000 PIDFILE=/var/run/php-fastcgi/php-fastcgi.pid CHILDREN=6 PHP5=/usr/bin/php5-cgi /usr/bin/spawn-fcgi -a $ADDRESS -p $PORT -P $PIDFILE -C $CHILDREN -u $FASTCGI_USER -g $FASTCGI_GROUP -f $PHP5

Make it executable by issuing the following command:

chmod +x /usr/bin/php-fastcgi

Important Security Considerations

If you’re planning to run applications that support file uploads (images, for example), the above configurations may expose you to a security risk by allowing arbitrary code execution. The short explanation for this behavior is that a properly crafted URI which ends in “.php”, in combination with a malicious image file that actually contains valid PHP, can result in the image being processed as PHP.

To mitigate this issue, you may wish to modify your configuration to include a try_files directive. Please note that this fix requires nginx and the php-fcgi workers to reside on the same server.

File: /etc/nginx/sites-available/www.example.com

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location ~ \.php$ { try_files $uri =404; include /etc/nginx/fastcgi_params; fastcgi_pass unix:/var/run/php-fastcgi/php-fastcgi.socket; fastcgi_index index.php; fastcgi_param SCRIPT_FILENAME /srv/www/www.example.com/public_html$fastcgi_script_name; }

Additionally, it’s a good idea to secure any upload directories your applications may use. The following configuration excerpt demonstrates securing an “/images” directory.

File: /etc/nginx/sites-available/www.example.com

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location ~ \.php$ { include /etc/nginx/fastcgi_params; if ($uri !~ "^/images/") { fastcgi_pass unix:/var/run/php-fastcgi/php-fastcgi.socket; } fastcgi_index index.php; fastcgi_param SCRIPT_FILENAME /srv/www/www.example.com/public_html$fastcgi_script_name; }

Enable and Start Services

Issue the following commands to enable the site:

cd /etc/nginx/sites-enabled/
ln -s /etc/nginx/sites-available/www.example.com

Create a file named /etc/init.d/php-fastcgi with the following contents:

File: /etc/init.d/php-fastcgi

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#!/bin/bash PHP_SCRIPT=/usr/bin/php-fastcgi FASTCGI_USER=www-data FASTCGI_GROUP=www-data PID_DIR=/var/run/php-fastcgi PID_FILE=/var/run/php-fastcgi/php-fastcgi.pid RET_VAL=0 case "$1" in start) if [[ ! -d $PID_DIR ]] then mkdir $PID_DIR chown $FASTCGI_USER:$FASTCGI_GROUP $PID_DIR chmod 0770 $PID_DIR fi if [[ -r $PID_FILE ]] then echo "php-fastcgi already running with PID `cat $PID_FILE`" RET_VAL=1 else $PHP_SCRIPT RET_VAL=$? fi ;; stop) if [[ -r $PID_FILE ]] then kill `cat $PID_FILE` rm $PID_FILE RET_VAL=$? else echo "Could not find PID file $PID_FILE" RET_VAL=1 fi ;; restart) if [[ -r $PID_FILE ]] then kill `cat $PID_FILE` rm $PID_FILE RET_VAL=$? else echo "Could not find PID file $PID_FILE" fi $PHP_SCRIPT RET_VAL=$? ;; status) if [[ -r $PID_FILE ]] then echo "php-fastcgi running with PID `cat $PID_FILE`" RET_VAL=$? else echo "Could not find PID file $PID_FILE, php-fastcgi does not appear to be running" fi ;; *) echo "Usage: php-fastcgi {start|stop|restart|status}" RET_VAL=1 ;; esac exit $RET_VAL

Start php-fastcgi and nginx by issuing the following commands:

chmod +x /etc/init.d/php-fastcgi
update-rc.d php-fastcgi defaults
/etc/init.d/php-fastcgi start
/etc/init.d/nginx start

Test PHP with FastCGI

Create a file called “test.php” in your site’s public_html directory with the following contents:

File: /srv/www/example.com/public\\_html/test.php

1	<?php phpinfo(); ?>

When you visit http://www.example.com/test.php in your browser, the standard “PHP info” output is shown. Congratulations, you’ve configured the nginx web server to use PHP-FastCGI for dynamic content!

More Information

You may wish to consult the following resources for additional information on this topic. While these are provided in the hope that they will be useful, please note that we cannot vouch for the accuracy or timeliness of externally hosted materials.

• The NGINX Homepage
• FastCGI Project Homepage
• PHP Documentation
• Basic NGINX Configuration