Infrastructure monitoring and alerting for hosts and services
What is this?
Nagios watches your servers and sends you an alert when something stops working.
Step 01
1# Ubuntu / Debian2sudo apt-get install -y nagios4 nagios-plugins-contrib apache23 4# RHEL / Fedora5sudo dnf install -y nagios nagios-plugins-all httpd6 7sudo systemctl enable nagios httpd8sudo systemctl start nagios httpd9 10# Default web UI: http://server/nagios11# Default user: nagiosadmin (set password during install)Step 02
1sudo nano /etc/nagios4/conf.d/hosts.cfg2 3define host {4 use generic-host5 host_name webserver16 alias Web Server 17 address 192.168.1.218 max_check_attempts 59}10 11sudo nano /etc/nagios4/conf.d/services.cfg12 13define service {14 use generic-service15 host_name webserver116 service_description HTTP17 check_command check_http18}19 20sudo nagios4 -v /etc/nagios4/nagios.cfg21sudo systemctl restart nagios41# Install mail utils2sudo apt-get install -y mailutils3 4# Edit contacts and commands:5sudo nano /etc/nagios4/conf.d/contacts.cfg6# define contact { contact_name admin; email admin@example.com; ... }7 8sudo systemctl restart nagios4Step 03
1sudo nagios4 -v /etc/nagios4/nagios.cfg2sudo systemctl status nagios43curl -I http://localhost/nagios4/Step 04
1# After editing configs:2sudo nagios4 -v /etc/nagios4/nagios.cfg3sudo systemctl reload nagios44 5# External commands (schedule downtime):6echo "[$(date +%s)] SCHEDULE_HOST_DOWNTIME;webserver1;$(date +%s);$(($(date +%s)+3600);1;0;0;Admin;Maintenance" | sudo tee /var/lib/nagios4/rw/nagios.cmdStep 05
1sudo systemctl status nagios2sudo nagios -v /etc/nagios/nagios.cfg3sudo tail -f /var/log/nagios/nagios.log