How to Install Cacti on Ubuntu Server and Centos

First step is changing root password ;
sudo passwd root
....

Second step , you install these packets.

apt-get install apache2
apt-get install php5
apt-get install php5-mysql
apt-get install php5-snmp
apt-get install libapache2-mod-php5 or apt-get install libapache2-mod-php
apt-get install snmpd
apt-get install mysql-client
apt-get install mysql-server
apt-get install rrdtool
apt-get update
apt-get install cacti
apt-get install cacti-spine
apt-get update

--
real time monitoring

https://www.youtube.com/watch?v=8cCP4j6LKG0

cd /usr/share/cacti/site/plugins
wget http://docs.cacti.net/_media/plugin:realtime-v0.5-2.tgz
mv plugin:realtime-v0.5-2.tgz realtime.tgz
tar -zvxf realtime.tgz

You can find last version ovf at this web site
 http://www.kevinnoall.com/blog/2015/03/06/cacti-virtual-appliance/comment-page-1/#comments
It think İt is my best version
http://www.kevinnoall.com/blog/2015/03/06/cacti-virtual-appliance/cacti_centos6_template_v2-3/
http://cactiez.cactiusers.org/docs/logininfo.html

Default Username admin
Password : Cactipw1!

nano /etc/resolv.conf

nameserver 8.8.8.8

nameserver 8.8.4.4
nano /etc/sysconfig/network-scripts/ifcfg-eth0

all plugins inside this folder cd /var/www/html/cacti/plugins