Adding a New Bleckmann Host to Nagios Monitoring
Adding a New Server to Nagios Monitoring
🔹 Step 1: Add DNS Entry (on Mercury Server)
Before anything else:
• Make sure the Nagios server can resolve the new server’s hostname.
• Log in to the Mercury server (your internal DNS server).
• Add the DNS entry (IP Hostname) for the new server.
🔹 Step 2: Define the New Server in Nagios
1. Log in to the Nagios server
Example: nagios.apoyar
2. Navigate to the machines config folder
cd /usr/local/etc/nagios/objects/machines
3. Create or edit the config for the new server
vi bleckmann.cfg
o Add the host definition for the new server (similar to existing entries).
o Save the file.
🔹 Step 3: Add Service Checks for the New Server
1. Go to the services configuration directory:
cd /usr/local/etc/nagios/objects/
2. Edit the services.cfg file:
vi services.cfg
o Add the new server under all required services (like disk, CPU, memory).
o Use the same format as other servers.
🔹 Step 4: Validate Nagios Configuration
Run the syntax check to ensure there are no errors:
/usr/local/bin/nagios -v /usr/local/etc/nagios/nagios.cfg
• Make sure "Total Warnings: 0" and "Total Errors: 0"
• Fix anything if it shows up
🔹 Step 5: Prepare the New Server for Monitoring
1. Create a nagios user:
adduser nagios
2. Create a bin folder:
cd /home/nagios
mkdir bin
3. Change ownership:
chown nagios:nagios /home/nagios/bin -R
🔹 Step 6: Install Required Nagios Plugins & Dependencies
Install the NRPE agent and required packages:
- Core plugins and dependencies
yum install nagios-plugins
yum install perl
yum install python3-psutil
ln -s /bin/python3 /usr/bin/python
- Perl modules
dnf install perl-Array-Unique
dnf install perl-File-Slurp
dnf install perl-Number-Format
dnf install nagios-plugins-perl
dnf install perl-LWP-Protocol-https
dnf install perl-List-MoreUtils
- EPEL and full NRPE plugin set
yum install epel-release -y
yum install nrpe nagios-plugins-disk nagios-plugins-load nagios-plugins-procs nagios-plugins-users nagios-plugins-swap nagios-plugins-http nagios-plugins-ping nagios-plugins-ssh -y
🔹 Step 7: Copy Custom Plugins
Go to the plugins directory:
cd /usr/lib64/nagios/plugins/
here, get all custom or missing plugins from an existing monitored server.
🔹 Step 8: Configure NRPE
Edit the NRPE configuration:
vi /etc/nagios/nrpe.cfg
• Copy configuration style and plugin command definitions from an existing server.
• Make sure all command[...] entries point to valid plugin scripts.
🔹 Step 9: Enable and Start NRPE
systemctl start nrpe.service
systemctl enable nrpe.service
systemctl status nrpe.service
Ensure it is:
• Active (running)
• Enabled
• No errors in status output
🔹 Step 10: Finalize in Nagios Dashboard
1. Restart Nagios process (from web UI or via command line).
2. After restart, the new server will appear on the dashboard.
3. Manually reschedule checks for all its services.
4. Wait until all checks turn green and OK.