Chapter 3. Using the Nagios Web Interface

Your Nagios system is now up and running. It will also send out notifications to people if something goes wrong. What we need now, is a way to be able to view current and historical information on which hosts and services are failing. Nagios offers just that! It comes with a web interface that can be used to view the status of all hosts and services, read logs, and generate reports. And that is just a small part of its functionality.

Using any browser, you can access almost any information Nagios keeps—statuses, performance data, history, and logs. With just a few clicks, you can check if all of your hosts and services are working correctly. The interface also offers the ability to change parts of a configuration on the fly. This means that you can, for example, disable host or service checks in just a few clicks. Nagios web pages are usually password protected. In many cases, they are also only accessible from within a trusted IP address—for example, only from the Intranet or a company VPN.

The ability to check the status of all hosts and services is a very valuable functionality. Usually, a notification that something is wrong should just be a trigger to investigate the problem. Being able to see the big picture via various views of the web interface is very useful. You can use different detailed views and see what is not working properly. Quick access to such information from all monitored machines in your network is a blessing in case of any problems. You can clearly see which hosts and services are working as they should, and which ones aren't.

Nagios can also show you a tree of your infrastructure that includes parent host mappings. This is a great way to see which machines are down, and which are assumed to be unreachable. In larger systems, where there are a lot of dependencies, being able to see this clearly is very useful.

The web interface also uses Nagios object structure to handle access rights. Nagios web interface is commonly configured in such a way that there is a single user who has access to all information. It is also possible to set up additional users based on actual contact names. These users will have access to only the hosts and services for which they are the people to be contacted. This way, the administrator of specific machines or host groups can log into the site and see only what he or she is authorized to see.