In this chapter, you learned the basics of Nagios as a tool for performing system monitoring. It can be used to ensure that services are working correctly, problems are detected earlier, and appropriate people are aware when something's wrong.

You learned the basic types of objects in Nagios—commands, hosts, services, time periods, contacts, as well as object grouping. You also found out about notifications and escalations, which can be used to notify administrators about problems.

The chapter also introduced the concept of dependencies that helps in understanding the root cause of complex problems.

The next chapter will guide you through the process of installing Nagios and the standard Nagios plugins.