This section discusses the installation of Nagios 3. The following points are discussed:
Upgrading from previous versions
Prerequisites
Obtaining Nagios
Setting up users and groups
Nagios compilation
Registering Nagios as a system service
Let us look at each point in detail.
If you already have Nagios 1 or 2, upgrading to Nagios 3 would be worthwhile. In such cases, you should proceed with the same steps as when performing a fresh installation. You need to use the same user name, groups and directories that you have used for previous Nagios installations.
It is also necessary to stop all Nagios processes before performing an upgrade. This can usually be done by invoking the following command:
/etc/init.d/nagios stop
This way, both Nagios and the plugins will install smoothly. As Nagios 3 configuration parameters are backwards compatible, your current configuration will work fine after upgrading.