Chapter 2. Nagios Core installation and configuration

Procedure

1. Install the prerequisites:

   [user@nagios]# yum install -y httpd php php-cli gcc glibc glibc-common gd gd-devel net-snmp openssl openssl-devel wget unzip

2. Open port 80 for httpd:

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

3. Create a user and group for Nagios Core:

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

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

   [user@nagios]# wget --inet4-only https://assets.nagios.com/downloads/nagioscore/releases/nagios-4.3.1.tar.gz
   [user@nagios]# wget --inet4-only http://www.nagios-plugins.org/download/nagios-plugins-2.2.1.tar.gz
   [user@nagios]# tar zxf nagios-4.3.1.tar.gz
   [user@nagios]# tar zxf nagios-plugins-2.2.1.tar.gz
   [user@nagios]# cd nagios-4.3.1

5. Run ./configure:

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

6. Compile the Nagios Core source code:

   [user@nagios]# make all

7. Install Nagios source code:

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

8. Copy the event handlers and change their ownership:

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

9. Run the pre-flight check:

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

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

    [user@nagios]# cd ../nagios-plugins-2.2.1
    [user@nagios]# ./configure --with-nagios-user=nagios --with-nagios-group=nagios
    [user@nagios]# make
    [user@nagios]# make install

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

    [user@nagios]$ sudo 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 username too.

    Also 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 as a service and enable it:

   [user@nagios]# chkconfig --add nagios
   [user@nagios]# chkconfig --level 35 nagios on

2. Start the Nagios Core daemon and Apache:

   [user@nagios]# systemctl start nagios
   [user@nagios]# systemctl enable httpd
   [user@nagios]# systemctl start httpd

Procedure

1. With Nagios up and running, log in to the web user interface:

   http://IP_ADDRESS/nagios

   Nagios Core will prompt for a user name and password.

2. Input the login and password of the default Nagios Core user.