In order for Cacti to function properly, please edit the following files:

/etc/cacti/db.php
/etc/cron.d/cacti
/etc/httpd/conf.d/cacti.conf

Important:
We recommend that you turnoff SELinux with setenforce 0 during the installation of cacti.

The installation procedure, briefly summarized:

1) Create the cacti MySQL database:

   # mysqladmin -u root -p create cacti

2) Import the default cacti database:

   # mysql -u root -p cacti < /usr/share/doc/cacti/cacti.sql

3) Create the cacti database user:

   # mysql -u root -p
   mysql> GRANT ALL ON cacti.* TO cactiuser@localhost IDENTIFIED BY 'cactiuser';
   mysql> flush privileges;

   (Use a different password in the above GRANT command.)
  
4) Import mysql_tzinfo_to_sql to MySQL

   # mysql_tzinfo_to_sql /usr/share/zoneinfo | mysql -u root -p mysql
  
5) Set SELECT permission for cactiuser to mysql.time_zone_name

   # mysql -u root -p
   mysql> use mysql;
   mysql> GRANT SELECT ON mysql.time_zone_name TO cactiuser@localhost;
   mysql> flush privileges;

6) Then visit http://localhost/cacti/ to complete the installation.

Cacti's install procedure is not fully compatible with mod_security. If you use
mod_security, please uncomment the SecRuleRemoveById lines in
/etc/http/conf.d/cacti.conf.

Cacti should work with SELinux. If you cannot get it to work, please file a bug.