In this chapter, we discussed how to set up Nagios and monitor hosts from a central place. We looked at using Nagios templates, hostgroups, and services for managing client machines. We also discussed setting up Nagios alerts, controlling the Nagios process, and executing commands from the web interface. We learned about writing Nagios plugins and working with the NRPE plugin for CPU as well as disk usage monitoring. Then, we discussed Puppet, which is used to centrally manage the configuration. We tested our Puppet setup. Then, we saw how ClusterSSH can be used to replicate commands over a set of host machines and monitor them using xterm.

In the next chapter, you will learn about process management. You will learn about running processes, monitoring processes, and background processes.