Think LAMP - Web Development, Linux Administration and Networking

I got inspired by the 10 commandments for system administrators from http://www.linux.com/feature/44315
This is my list:
1. Be WARY about COST CUTTING.
(cheap hardware, cables, labour)
2. KNOW THE NETWORK well.
(keep network, routing diagrams, track public and private IP, label cables if necessary)
3. ESTABLISH STRONG SECURITY POLICIES in the system.
(Security Access, File Permission, good password choice, encryption, SetUID, LDAP, [...]

If you wish to check that your web application is working fine (people are able to login), you can run a script to automate the login process. It is possible to use cron to do it but with nagios, you could do much more. Nagios is highly configurable and it makes perfect sense to write [...]