Nagios Monitoring

Nagios is an open source monitoring platform for 24/7 IT infrastructure monitoring.

Host Definition

define host {
    use                     linux-server
    host_name               webserver01
    alias                   Web Server 01
    address                 192.168.1.10
    max_check_attempts      5
}

Service Definitions

define service {
    use                     generic-service
    host_name               webserver01
    service_description     SSH
    check_command           check_ssh
}

define service {
    use                     generic-service
    host_name               webserver01
    service_description     HTTP
    check_command           check_http
}

NRPE Agent

sudo dnf install -y nrpe nagios-plugins-all

/etc/nagios/nrpe.cfg
allowed_hosts=127.0.0.1,192.168.1.5
command[check_load]=/usr/lib64/nagios/plugins/check_load -w 15,10,5 -c 30,25,20
command[check_disk]=/usr/lib64/nagios/plugins/check_disk -w 20% -c 10% -p /
sudo systemctl enable --now nrpe

Conclusion

Nagios enables proactive monitoring to detect issues before they impact users.