How to setup check CPU in Nagios alert?

How to setup check_CPU in Nagios alert

Step 1:

Log in to your Ubuntu or Centos server as a user with sudo privileges. You can use SSH or directly access the server.

 ssh root@Ip

Step 2:

Please go to the libexec path and Create a new script file, such as check_cpu, in the specified path. The script should check if the CPU in the server high and low.

 cd /usr/local/nagios/libexec 
        Or
 cd /usr/lib/nagios/plugins/

Step 3:

create a new script file

  vi check_cpu

Please copy the below commands, and paste the check_cpu file, and save the file.

 #!/bin/bash
 # Define your remote server's SSH details
 #SSH_USER="your_ssh_user"
 #SSH_HOST="remote_server_hostname_or_ip"
 # SSH command to collect CPU utilization (example command, you can modify it)
 #SSH_CMD="top -bn1 | grep 'Cpu(s)' | awk '{print \$2 + \$4}'"
 # SSH into the remote server and execute the command
 #CPU_USAGE=$(ssh -l $SSH_USER $SSH_HOST "$SSH_CMD")
 # Check the CPU usage and return an appropriate message
 if (( $(echo "$CPU_USAGE >= 90" | bc -l) )); then
 echo "CRITICAL - CPU Usage: $CPU_USAGE%"
 exit 2
 elif (( $(echo "$CPU_USAGE >= 80" | bc -l) )); then
 echo "WARNING - CPU Usage: $CPU_USAGE%"
 exit 1
 else
 echo "OK - CPU Usage: $CPU_USAGE%"
 exit 0
 fi

Step 4:

Give permission to the check_cpu file and follow the below command:

 chmod 755 check_cpu

Step 5:

Edit the /usr/local/nagios/etc/nrpe.cfg configuration file and search for COMMAND DEFINITIONS sections. Here you can define or update check commands.

 vi /usr/local/nagios/etc/nrpe.cfg
          or
 vi /etc/nagios/nrpe.cfg

Please update the below command for the CPU check.

 command[check_cpu]=/usr/local/nagios/libexec/check_cpu
                   or
 command[check_cpu]=/usr/lib/nagios/plugins/check_cpu

Step 6:

Next, restart the NRPE service. Now it is ready to listen to requests from the Nagios server

 systemctl restart nrpe.service
              Or
 systemctl restart nagios-nrpe-server.service

check the nrpe status

 systemctl status nrpe.service
            or
 systemctl status nagios-nrpe-server.service

open the Nagios server

Step 7:

Please open the below for the configuration path

   cd /usr/local/nagios/etc/servers/

open the configuration file using the below commands

    vi testserver2.cfg

Add the below lines for pm2 checking the configuration and save it

Step 8:

Save the configuration file

  define service {
 use generic-service ; Name of service template to use
 host_name testserver2
 service_description cpu_service
 check_command check_nrpe!check_cpu
 contact_groups admins
 notifications_enabled 1
 }

And finally, restart Nagios to apply recent configuration changes:

   systemctl restart nagios

It is working cpu_service status the below snapshot