How does Nagios handle alerts and notifications?

Nagios is an open-source system and network monitoring tool that can monitor servers, network devices, applications, etc. It generates alerts and sends notifications when problems are detected. The process of handling alerts and notifications in Nagios is as follows:

1. When an issue is detected by the monitoring system, an alert is generated and sent to the Nagios monitoring server.
2. On the monitoring server, Nagios will handle this alert based on pre-defined monitoring rules and strategies. For example, administrators can receive email notifications when a failure occurs.
3. Nagios will determine how to handle alerts based on monitoring rules and policies, which can include sending email, SMS, PagerDuty, Slack, etc. notifications to relevant personnel.
4. After receiving the notification, the relevant personnel will take appropriate actions to resolve the issue and then mark it as resolved.

In general, Nagios helps administrators discover and resolve issues promptly, ensuring system stability and security through monitoring, alert generation, and notification sending processes.