Running Question2Answer On Nginx (LEMP) On Debian Squeeze/Ubuntu 12.10

Version 1.0
Author: Falko Timme <ft [at] falkotimme [dot] com>
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Last edited 10/29/2012

This tutorial shows how you can install and run a Question2Answer web site on a Debian Squeeze or Ubuntu 12.10 system that has nginx installed instead of Apache (LEMP = Linux + nginx (pronounced "engine x") + MySQL + PHP). nginx is a HTTP server that uses much less resources than Apache and delivers pages a lot of faster, especially static files. Question2Answer is a free and open source platform for Q&A sites.

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

1 Preliminary Note

I want to install Question2Answer in a vhost called www.example.com/example.com here with the document root /var/www/www.example.com/web.

You should have a working LEMP installation, as shown in these tutorials:

• Installing Nginx With PHP5 And MySQL Support On Debian Squeeze
• Installing Nginx With PHP5 (And PHP-FPM) And MySQL Support On Ubuntu 12.10

A note for Ubuntu users:

Because we must run all the steps from this tutorial with root privileges, we can either prepend all commands in this tutorial with the string sudo, or we become root right now by typing

sudo su

2 Installing APC

APC is a free and open PHP opcode cacher for caching and optimizing PHP intermediate code. It's similar to other PHP opcode cachers, such as eAccelerator and XCache. It is strongly recommended to have one of these installed to speed up your PHP page.

APC can be installed as follows:

apt-get install php-apc

If you use PHP-FPM as your FastCGI daemon (like in Installing Nginx With PHP5 (And PHP-FPM) And MySQL Support On Ubuntu 12.10), restart it as follows:

/etc/init.d/php5-fpm restart

If you use lighttpd's spawn-fcgi program as your FastCGI daemon (like in Installing Nginx With PHP5 And MySQL Support On Debian Squeeze), we must kill the current spawn-fcgi process (running on port 9000) and create a new one. Run

netstat -tap

to find out the PID of the current spawn-fcgi process:

root@server1:~# netstat -tap
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 *:sunrpc                *:*                     LISTEN      734/portmap
tcp        0      0 *:www                   *:*                     LISTEN      2987/nginx
tcp        0      0 *:ssh                   *:*                     LISTEN      1531/sshd
tcp        0      0 *:57174                 *:*                     LISTEN      748/rpc.statd
tcp        0      0 localhost.localdom:smtp *:*                     LISTEN      1507/exim4
tcp        0      0 localhost.localdom:9000 *:*                     LISTEN      1542/php5-cgi
tcp        0      0 localhost.localdo:mysql *:*                     LISTEN      1168/mysqld
tcp        0     52 server1.example.com:ssh 192.168.0.198:2462      ESTABLISHED 1557/0
tcp6       0      0 [::]:www                [::]:*                  LISTEN      2987/nginx
tcp6       0      0 [::]:ssh                [::]:*                  LISTEN      1531/sshd
tcp6       0      0 ip6-localhost:smtp      [::]:*                  LISTEN      1507/exim4
root@server1:~#

In the above output, the PID is 1542, so we can kill the current process as follows:

kill -9 1542

Afterwards we create a new spawn-fcgi process:

/usr/bin/spawn-fcgi -a 127.0.0.1 -p 9000 -u www-data -g www-data -f /usr/bin/php5-cgi -P /var/run/fastcgi-php.pid

3 Installing Question2Answer

The document root of my www.example.com web site is /var/www/www.example.com/web - if it doesn't exist, create it as follows:

mkdir -p /var/www/www.example.com/web

Because Question2Answer comes as a .zip file, we need to install unzip:

apt-get install unzip

Next we download Question2Answer (http://www.question2answer.org/question2answer-latest.zip) and place it in our document root:

cd /tmp
mkdir q2a
cd q2a
wget http://www.question2answer.org/question2answer-latest.zip
unzip question2answer-latest.zip
rm -f question2answer-latest.zip
cd question2answer/
mv * .htaccess /var/www/www.example.com/web/

It is recommended to make the document root and the Question2Answer files in it writable by the nginx daemon which is running as user www-data and group www-data:

chown -R www-data:www-data /var/www/www.example.com/web

If you haven't already created a MySQL database for Question2Answer (including a MySQL Question2Answer user), you can do that as follows (I name the database q2a in this example, and the user is called q2a_admin, and his password is q2a_admin_password):

mysqladmin -u root -p create q2a

mysql -u root -p

GRANT ALL PRIVILEGES ON q2a.* TO 'q2a_admin'@'localhost' IDENTIFIED BY 'q2a_admin_password';
GRANT ALL PRIVILEGES ON q2a.* TO 'q2a_admin'@'localhost.localdomain' IDENTIFIED BY 'q2a_admin_password';

FLUSH PRIVILEGES;

quit;

Next we create an nginx vhost configuration for our www.example.com vhost in the /etc/nginx/sites-available/ directory as follows:

vi /etc/nginx/sites-available/www.example.com.vhost

server {
       listen 80;
       server_name www.example.com example.com;
       root /var/www/www.example.com/web;

       if ($http_host != "www.example.com") {
                 rewrite ^ http://www.example.com$request_uri permanent;
       }

       index index.php index.html index.htm default.html default.htm;

       location = /favicon.ico {
                log_not_found off;
                access_log off;
       }

       location = /robots.txt {
                allow all;
                log_not_found off;
                access_log off;
       }

       # Deny all attempts to access hidden files such as .htaccess, .htpasswd, .DS_Store (Mac).
       location ~ /\. {
                deny all;
                access_log off;
                log_not_found off;
       }

       location / {
                try_files $uri $uri/ /index.php?qa-rewrite=$uri&$args;
       }

       location ~ \.php$ {
                try_files $uri =404;
                fastcgi_split_path_info ^(.+\.php)(/.+)$;
                fastcgi_pass unix:/var/run/php5-fpm.sock; # use this if PHP-FPM is running on Unix socket /var/run/php5-fpm.sock (Ubuntu 12.10 default)
                #fastcgi_pass 127.0.0.1:9000; # use this if PHP-FPM is running on TCP port 9000 (Debian Squeeze default)
                include /etc/nginx/fastcgi_params;
                fastcgi_index index.php;
       }
}

To enable that vhost, we create a symlink to it from the /etc/nginx/sites-enabled/ directory:

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

Reload nginx for the changes to take effect:

/etc/init.d/nginx reload

Next rename qa-config-example.php to qa-config.php...

cd /var/www/www.example.com/web/
mv qa-config-example.php qa-config.php

... and open the file:

vi qa-config.php

Fill in the correct database details:

[...]
        define('QA_MYSQL_HOSTNAME', 'localhost'); // try '127.0.0.1' or 'localhost' if MySQL on same server
        define('QA_MYSQL_USERNAME', 'q2a_admin');
        define('QA_MYSQL_PASSWORD', 'q2a_admin_password');
        define('QA_MYSQL_DATABASE', 'q2a');
[...]