Chapter 2. Nagios Core installation and configuration

Procedure

1. Install the prerequisites:

   Example

   [root@nagios ~]# dnf install -y httpd php php-cli gcc glibc glibc-common gd gd-devel net-snmp openssl openssl-devel wget unzip make

2. If you are using a firewall, open port 80 for httpd:

   Example

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

3. Create a user and group for Nagios Core:

   Example

   [root@nagios ~]# useradd nagios
   [root@nagios ~]# passwd nagios
   [root@nagios ~]# groupadd nagcmd
   [root@nagios ~]# usermod -a -G nagcmd nagios
   [root@nagios ~]# usermod -a -G nagcmd apache

4. Download the latest version of Nagios Core and Plug-ins:

   Example

   [root@nagios ~]# wget --inet4-only https://assets.nagios.com/downloads/nagioscore/releases/nagios-4.4.5.tar.gz
   [root@nagios ~]# wget --inet4-only http://www.nagios-plugins.org/download/nagios-plugins-2.3.3.tar.gz
   [root@nagios ~]# tar zxf nagios-4.4.5.tar.gz
   [root@nagios ~]# tar zxf nagios-plugins-2.3.3.tar.gz
   [root@nagios ~]# cd nagios-4.4.5

5. Run ./configure:

   Example

   [root@nagios nagios-4.4.5]# ./configure --with-command-group=nagcmd

6. Compile the Nagios Core source code:

   Example

   [root@nagios nagios-4.4.5]# make all

7. Install Nagios source code:

   Example

   [root@nagios nagios-4.4.5]# make install
   [root@nagios nagios-4.4.5]# make install-init
   [root@nagios nagios-4.4.5]# make install-config
   [root@nagios nagios-4.4.5]# make install-commandmode
   [root@nagios nagios-4.4.5]# make install-webconf

8. Copy the event handlers and change their ownership:

   Example

   [root@nagios nagios-4.4.5]# cp -R contrib/eventhandlers/ /usr/local/nagios/libexec/
   [root@nagios nagios-4.4.5]# chown -R nagios:nagios /usr/local/nagios/libexec/eventhandlers

9. Run the pre-flight check:

   Example

   [root@nagios nagios-4.4.5]# /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg

10. Make and install the Nagios Core plug-ins:

    Example

    [root@nagios ~]# cd ../nagios-plugins-2.3.3
    [root@nagios nagios-plugins-2.3.3]# ./configure --with-nagios-user=nagios --with-nagios-group=nagios
    [root@nagios nagios-plugins-2.3.3]# make
    [root@nagios nagios-plugins-2.3.3]# make install

11. Create a user for the Nagios Core user interface:

    Example

    [root@nagios nagios-plugins-2.3.3]# htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin

    Important

    If adding a user other than nagiosadmin, ensure the /usr/local/nagios/etc/cgi.cfg file gets updated with the user name too.

12. Modify the /usr/local/nagios/etc/objects/contacts.cfg file with the user name, full name, and email address as needed.

Procedure

1. Add Nagios Core and Apache as a service:

   Example

   [root@nagios ~]# systemctl enable nagios
   [root@nagios ~]# systemctl enable httpd

2. Start the Nagios Core daemon and Apache:

   Example

   [root@nagios ~]# systemctl start nagios
   [root@nagios ~]# systemctl start httpd