1) Install Nagios. Type this command line:
2) It will go through, and ask you about what mail server you want to use:
3) Choose your type of email configuration.
4) It will then ask you about the domain name you want to have email sent from. Again, fill that out based upon your needs.
5) It will ask you what password you want to use.
6) Confirm your password.
7) Installing the application.
8) We need to edit a few files. Start by opening /etc/nagios3/nagios.cfg. Use this command:
9) Search for check_external_commands, and turn the check_external_commands=0 into check_external_commands=1
10) Now, restart apache by running:
11) We need to edit /etc/group. There should be a line like this in there:
Change to this:
12) Now, we need to edit the /var/lib/nagios3/rw files permission with:
13) Again, restart your nagios3 and apache services.
14) If you want to monitor http and disk space, type this command line:
15) Change to this.
16) Do the same thing for this file:
17) Change to this.
19) And you should be good to go! Happy monitoring!