(What is Nagios? Nagios is an application for system and network monitoring. It can monitor the host and service under the conditions you set, and give alarm information when the status gets worse and better. Nagios was originally designed to run on Linux systems, but it can also run on UNIX like systems. Nagios further features include:
Monitoring network services (SMTP, POP3, HTTP, NNTP, Ping, etc.);
Monitor host resources (processor load, disk utilization, etc.);
Simple plug-in design makes it easy for users to extend their service detection methods;
Parallel service checking mechanism;
Have the ability to define the network hierarchy, and use the definition of parent host to express the relationship between network hosts. This relationship can be used to find and clarify the downtime or unreachable status of hosts;
Send the alarm to the contact person (via email, SMS, user-defined methods) when the service or host problem is generated and solved;
It has the function of defining event handle, which can obtain more problem location when the host or service event occurs;
Automatic log rollback;
It can support and realize redundant monitoring of the host;
The optional web interface is used to view the current network status, notification and fault history, log files, etc;)