How to install Nagios client (NRPE) on CentOS

You need to do the installation and basic client configuration on a remote server to monitor your host and services with Nagios Core. 

Step 1: First of all you need to install all required packages. 

# yum install gcc glibc glibc-common gd gd-devel make net-snmp openssl-devel vim wget xinetd

Step 2: Create a user using the below command. 

# useradd -s /usr/sbin/nologin nagios

Step 3: Download the required packages by using the wget command. 

# wget https://github.com/NagiosEnterprises/nrpe/releases/download/nrpe-4.1.0/nrpe-4.1.0.tar.gz 

# wget https://nagios-plugins.org/download/nagios-plugins-2.4.7.tar.gz

Step 4: Now extract downloaded files to compile. 

# tar xzf nagios-plugins-2.4.7.tar.gz 
# cd nagios-plugins-2.4.7 
# ./configure 
# make 
# make install 

** Now extract nrpe file as well ** 
# tar xzf nrpe-4.1.0.tar.gz 
# cd nrpe-4.1.0 
# ./configure 
# make all 
# make install-plugin; 
# make install-daemon; 
# make install-daemon-config; 
# make install-xinetd

Step 5: Set up permissions for required directories. 

# chown nagios:nagios /usr/local/nagios 
# chown -R nagios:nagios /usr/local/nagios/libexec

Step 6: Make an entry into /etc/services 

# echo "nrpe 5666/tcp # NRPE" >> /etc/services

Sample Entry:

Step 7: Add Nagios server ip in to /etc/xinetd.d/nrpe file

# sed -i 's/127.0.0.1/127.0.0.1 <nagios-server-ip>/g' /etc/xinetd.d/nrpe

Note: Replace <nagios-server-ip> with your nagios core IP.

Step 8: Restart the service and check if it is configured correctly or not. 

The output should be like this. 

# systemctl restart xinetd.service 
# /usr/local/nagios/libexec/check_nrpe -H 127.0.0.1

That’s it!! You are good to go.

NOTE: If you are using iptables or firewall in your servers then you need to allow the 5666 port. 

Check out more related Nagios information