Extend prerequisites for install Centreon from packages

doc/en/installation/from_packages.rst

@@ -4,7 +4,7 @@
 Using packages
 ==============
 
-Centreon supplies RPM for its products via the Centreon Enterprise Server (CES) solution Open Sources version available free of charge on our repository.
+Centreo supplies RPM for its products via the Centreon Open Sources version available free of charge on our repository (ex CES).
 
 These packages have been successfully tested on CentOS and Red Hat environments in 6.x and 7.x versions.
 
@@ -12,7 +12,7 @@ These packages have been successfully tested on CentOS and Red Hat environments
 Prerequisites
 *************
 
-To install Centreon software from the CES repository, you should first install the file linked to the repository.
+To install Centreon software from the repository, you should first install the file linked to the repository.
 
 Perform the following command from a user with sufficient rights.
 
@@ -38,12 +38,18 @@ The repository is now installed.
 Any operating system
 --------------------
 
+Disable SELinux
+^^^^^^^^^^^^^^^
+
 SELinux should be disabled; for this, you have to modify the file "/etc/sysconfig/selinux" and replace "enforcing" by "disabled":
 
 ::
 
     SELINUX=disabled
 
+PHP timezone
+^^^^^^^^^^^^
+
 PHP timezone should be set; go to /etc/php.d directory and create a file named php-timezone.ini who contain the following line :
 
 ::
@@ -52,8 +58,38 @@ PHP timezone should be set; go to /etc/php.d directory and create a file named p
 
 After saving the file, please don't forget to restart apache server.
 
+Firewall
+^^^^^^^^
+
+Add firewall rules or disable it. To disable it execute folowwing commands:
+
+* **iptables** (CentOS v6) ::
+
+    # /etc/init.d/iptables save
+    # /etc/init.d/iptables stop
+    # chkconfig iptables off
+
+* **firewalld** (CentOS v7) ::
+
+    # systemctl stop firewalld
+    # systemctl disable firewalld
+    # systemctl status firewalld
+
+DataBase Management System
+^^^^^^^^^^^^^^^^^^^^^^^^^^
+
 The Mysql database server should be available to complete installation (locally or not). MariaDB is recommended.
 
+For CentOS / RHEL in version 7, it is necessary to modify **LimitNOFILE** limitation.
+Edit **/etc/systemd/system/mysqld.service** file and change ::
+
+    LimitNOFILE=32000
+
+Save the file and execute the folowwing commands::
+
+    # systemctl daemon-reload
+    # service mysqld restart
+
 *********************
 Centreon installation
 *********************