Run Your Own Social Network Using elgg on RHEL / CentOS and Scientific Linux

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Elgg is an open-source and powerful social networking engine used to create your own social networking web site. In this How To, I am gonna show you how to build your own social network website, just like Facebook and Linkedin.

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Prerequisites

Elgg needs Apache, MySQL and PHP modules in order to build a social networking websites. So let us install the following necessary prerequisites first:

[root@server ~]# yum install mysql mysql-server httpd php php-mysql php-gd php-imap php-ldap php-odbc php-pear php-xml php-xmlrpc php-mbstring wget unzip -y

Open the Apache main configuration file and change from AllowOverride None to AllowOverride All:

[root@server ~]# vi /etc/httpd/conf/httpd.conf
 # AllowOverride controls what directives may be placed in .htaccess files.
 # It can be "All", "None", or any combination of the keywords:
 #   Options FileInfo AuthConfig Limit
 #
 AllowOverride All

Start/Restart MySQL and Apache services now:

[root@server ~]# /etc/init.d/mysqld restart

[root@server ~]# /etc/init.d/httpd restart

Create MySQL Database for elgg

Create a database for elgg called elggdb and database user called elgg with password ‘centos’:

[root@server ~]# mysql -u root -p
Enter password: ******
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.1.69 Source distribution

Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> create database elggdb;
Query OK, 1 row affected (0.02 sec)

mysql> create user 'elgg'@'localhost' identified by 'centos';
Query OK, 0 rows affected (0.00 sec)

mysql> GRANT ALL PRIVILEGES ON elggdb.* to 'elgg' IDENTIFIED BY 'centos';
Query OK, 0 rows affected (0.01 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.01 sec)

mysql> exit
Bye

Downloading elgg

[root@server ~]# wget http://elgg.org/getelgg.php?forward=elgg-1.8.15.zip

Extract the downloaded file:

[root@server ~]# unzip elgg-1.8.15.zip

Move the elgg folder to Apache root document directory:

[root@server ~]# mv elgg-1.8.15/ /var/www/html/elgg

Now go to /var/www/html/elgg/engine directory and copy the file settings.example.php to settings.php:

[root@server ~]# cd /var/www/html/elgg/engine/
[root@server engine]# cp settings.example.php settings.php

Open the file settings.php and enter the details of database name, database user, database password, hostname and database prefix as shown below:

[root@server engine]# vi settings.php 
/**
 * The database username
 *
 * @global string $CONFIG->dbuser
 * @name $CONFIG->dbuser
 */
$CONFIG->dbuser = 'elgg';

/**
 * The database password
 *
 * @global string $CONFIG->dbpass
 */
$CONFIG->dbpass = 'centos';

/**
 * The database name
 *
 * @global string $CONFIG->dbname
 */
$CONFIG->dbname = 'elggdb';

/**
 * The database host.
 *
 * For most installations, this is 'localhost'
 *
 * @global string $CONFIG->dbhost
 */
$CONFIG->dbhost = 'localhost';

/**
 * The database prefix
 *
 * This prefix will be appended to all Elgg tables.  If you're sharing
 * a database with other applications, use a database prefix to namespace tables
 * in order to avoid table name collisions.
 *
 * @global string $CONFIG->dbprefix
 */
$CONFIG->dbprefix = 'elgg_';

Create directory called data to upload photos, videos and profile icons etc. The directory should be created outside of the Apache root document folder for security reasons:

[root@server html]# mkdir data
[root@server html]# chmod 777 data/

Adjusting firewall and SELinux

Open the Apache default port 80 through your firewall/router and disable the SELinux:

[root@server html]# vi /etc/sysconfig/iptables
# Firewall configuration written by system-config-firewall
# Manual customization of this file is not recommended.
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -p udp -m state --state NEW --dport 3306 -j ACCEPT
-A INPUT -p tcp -m state --state NEW --dport 3306 -j ACCEPT
-A INPUT -p udp -m state --state NEW --dport 80 -j ACCEPT
-A INPUT -p tcp -m state --state NEW --dport 80 -j ACCEPT
-A INPUT -p udp -m state --state NEW --dport 53 -j ACCEPT
-A INPUT -p tcp -m state --state NEW --dport 53 -j ACCEPT
-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT

Restart the iptables to save the changes:

[root@server html]# /etc/init.d/iptables restart

Disable SELinux and reboot your system:

[root@server ~]# vi /etc/sysconfig/selinux 
# 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

Starting elgg installation

Open the web browser and navigate to http://ip-address/elgg/install.php or http://domain-name/elgg/install.php. Follow the on screen instructions:

Elgg Install : Welcome - Mozilla Firefox_001

You may get an error like in the below screen-shot.

Elgg Install : Requirements check - Mozilla Firefox_002

To get rid of this error, open the file .htaccess in the elgg directory and edit as follows. If .htaccess file doesn’t exist, create it by copying the htaccess_dist file in the elgg directory to .htaccess.

[root@server ~]# vi /etc/httpd/conf/httpd.conf 
[root@server ~]# cd /var/www/html/elgg/
[root@server elgg]# cp htaccess_dist .htaccess

Now open the .htaccess file in any editor. Uncomment the line 94 and set it as shown below:

[root@server elgg]# vi .htaccess 
## Line no 94 - Uncomment and set as below ##
RewriteBase /elgg/

Save and exit the file. Restart the httpd service and try again the installer. This time the error will be gone.

Elgg Install : Requirements check - Mozilla Firefox_003

Now enter the Site Name, Site Administrator email ID and data directory path as shown below. Click Next.

Elgg Install : Configure site - Mozilla Firefox_004

Now create the Admin account for elgg. Fill up details and click Next.

Elgg Install : Create admin account - Mozilla Firefox_006

Now your new social network has been created. Click Go to site to get started.

Elgg Install : Finished - Mozilla Firefox_007

This is how your Administration Dashboard will appear.

Unixmen Community: Dashboard - Mozilla Firefox_008

Click on the View Site link on the upper right corner of Dashboard page. This is how your home page of your social network website will appear.

Unixmen Community: All Site Activity - Mozilla Firefox_009

From here, the users can create new blogs, pages, files, groups and so on.

For questions please refer to our Q/A forum at : http://ask.unixmen.com/

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