How to Install Nagios Core Server on CentOS 7

Nagios Core is free and open source widely used monitoring tool which can be used for monitoring Linux servers, Windows servers, Network devices and other applications. Nagios provides alerting services (SMS, Email etc.) for abnormal utilization and issues for Attributes CPU load, Memory usage, Disk usage, Logged in users, Running processes etc. and Services HTTP, FTP, SSH, SMTP, POP3, SNMP etc.

This article describes How to Install Nagios Server on CentOS7. Nagios Core packages are not available in CentOS7 base repository and it can be installed using EPEL repository.

Step 1. Setup EPEL Repository: Follow the article "How to Install EPEL Repository on CentOS 7" using yum command on CentOS 7.

Step 2. Nagios Packages: Run the following yum command to install Nagios packages and its dependencies:

[root@linuxcnf ~]# yum install nagios -y Loaded plugins: fastestmirror ……………… Installed:   nagios.x86_64 0:4.4.3-1.el7 Dependency Installed:   apr.x86_64 0:1.4.8-5.el7                 apr-util.x86_64 0:1.5.2-6.el7 ……………….   php-common.x86_64 0:5.4.16-46.1.el7_7 Complete! [root@linuxcnf ~]#

Step 3. Start Services: Start Nagios and httpd service and enable on system boot up:

[root@linuxcnf ~]# systemctl start nagios httpd [root@linuxcnf ~]# systemctl enable nagios httpd Created symlink from /etc/systemd/system/multi-user.target.wants/nagios.service to /usr/lib/systemd/system/nagios.service. Created symlink from /etc/systemd/system/multi-user.target.wants/httpd.service to /usr/lib/systemd/system/httpd.service. [root@linuxcnf ~]#

Step 4. Firewall Configuration: Configure firewall to allow clients to access NFS Share:

[root@linuxcnf ~]# firewall-cmd --permanent --zone=public --add-port=80/tcp success [root@linuxcnf ~]# firewall-cmd --reload success [root@linuxcnf ~]#

Step 4. Reset Password: Reset Nagios authentication using below command in case facing issue in Login on Nagios Dashboard:

[root@linuxcnf ~]# htpasswd -m /etc/nagios/passwd nagiosadmin New password: Re-type new password: Updating password for user nagiosadmin [root@linuxcnf ~]#

Step 5. Validation: Now access Nagios dashboard from any browser using Server IP address or host name and you will get Nagios dashboard as shown below:

Done!!! Nagios Server has been installed successfully. Now follow the article “How to addLinux Host to Nagios Monitoring Server in CentOS 7” to integrated devices or service for monitoring in Nagios Server.